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DevinT
01-25-2012, 02:01 PM
I've had many members ask me about steels that are used in knives so I've decided to start a thread that will explain why we use what we do.

Wear resistance, toughness, sharpenability, edge stablity, stain resistance are some of the main subjects that we will cover.

We've made knives out of O-1, 1065, 1075, 1095, 1084, 1086v, 52100, 440-C, AEB-L, mystery carbon, super wear resistant, PM stainless,154cm, cpm 154, D-2, spray form D-2, ATS-34, S-30V, L-3, 3-V, cpm M-4, vanadus 4 extra, niolox/SB1, L-6, O-2, 15n20, A-2, 19c27, 12c27, 425, spicy white, 5160, 9260, and several types of recycled steels such as chain saw bars, lawn mower blades, circular saw blades, coil and leaf springs, planer blades, etc. all come to mind. I'm sure that I've forgotten some.

We plan on trying several other steels in the future, to see if there is any thing better than what we are using.

The steels that we have settled on so far are; AEB-L, PM stainless (to remain nameless), super wear resistant (to remain nameless), and mystery carbon (also to remain nameless).

Some of the steels that we have tried have been a big disapointment, and some have been a big suprise.

More to come.

Hoss

Adagimp
01-25-2012, 02:07 PM
Love this idea.

WildBoar
01-25-2012, 02:17 PM
This is great. I can only imagine how much time you burn on phone calls, emails, etc. trying to educate the great unwashed masses :O

There are bits and pieces spread through a handful of threads in your vendor forum, but it will be great having all the info consolidated.

JohnnyChance
01-25-2012, 02:37 PM
The steels that we have settled on so far are; AEB-L, PM stainless (to remain nameless), super wear resistant (to remain nameless), and mystery carbon (also to remain nameless).

52100? Or is the super wear resistant carbon and mystery carbon taking over for 52100 in your lineup?

DevinT
01-25-2012, 02:47 PM
I still like 52100, 19c27, spicy white, niolox and a few others, however, I don't want to offer too many steels and the ones chosen may have a slight advantage.

Hoss

JMJones
01-25-2012, 03:52 PM
Have you all worked with W-2, i didnt see it on the list?

Luke_G
01-25-2012, 04:22 PM
May I ask how your "PM stainless" and "Super wear resistant" compare to R2 (which Tanaka and Mr. Itou are using)? I absolutely have nothing but good to say about it.

tk59
01-25-2012, 04:38 PM
May I ask how your "PM stainless" and "Super wear resistant" compare to R2 (which Tanaka and Mr. Itou are using)? I absolutely have nothing but good to say about it.
I have the pm stainless and I will say that I would be very impressed if the R2 in either can match it. It's significantly nicer than SG series, SRS-15, zdp-189, etc.). I'm testing the DT-super now. So far, I can say it is nice to sharpen (just two trials so far) but not quite as nice as other DT steels (takes a little more time) and it gets very sharp but the DT-pm is one of those steels that really "likes" to be sharp. It is probably my favorite steel so far and definitely my favorite stainless. I've tried out knives made from many steels but not R2. Sorry. After the DT-pm, I might choose Niolox or AEB-L.

Larrin
01-25-2012, 04:42 PM
It's difficult to compare to R2 because there's little information available on the steel.

DevinT
01-26-2012, 02:50 PM
Wear resistance.

Does it "hold an edge" is the question I get more than any other. In custom knives it has more interest than any other subject. I've heard lots of tall tales and exaggerations about this over the years.

Edge holding is the ability for a knife to keep cutting well in service. A properly sharpened knife will have a diameter of .4 micron at the edge. With use the diameter gets larger until it does not cut well, usually > 1 micron diameter at the edge. There is no reason to buy a custom knife unless it has excellent or superior edge holding.

Most steels come in the annealed condition and require hardening and tempering. Annealed steels have very low wear resistance which allows them to be worked easily. There are two things in properly heat treated steel that contribute to wear resistance. The first is the hardened matrix (martensite), and the second are the carbides. The amount of carbide volume, size, hardness, and distribution of the carbides all affect wear resistance and edge holding. Vanadium and tungsten carbides are harder than chrome and iron carbides. Steels with more carbides are more wear resistant than those with less. A certain amount of the carbide dissolves in hardening putting alloy and carbon in to the matrix making it hard and wear resistant.

Hardness affects edge holding. An increase of 2 points in Rockwell hardness will generally increase edge holding by about 20%. Improperly hardened and tempered blades having retained austenite (incomplete hardening) will be softer and not as wear resistant. Retained austenite also affects how much of a burr is formed and how easy it is to remove from a knife's edge while sharpening.

Lastly, the keener the edge the faster a knife will become dull. The coarser the stone used in sharpening, the longer it will hold that edge. I think that in general most knife nuts over sharpen.

To summarize, the proper selection of steels given the correct heat treatment along with correct sharpening will produce a knife with superior edge holding, give years of service, and will be a joy to use.

More to come.

Hoss

Marko Tsourkan
01-26-2012, 03:04 PM
Excellent post.

Larrin
01-26-2012, 03:59 PM
Wear resistance contributes primarily to edge holding for slicing. This is where coarse edges also lead to longer edge holding. Coarse edges + high wear resistance + slicing = long edge retention. For push cutting/chopping wear resistance and coarse edges are not very helpful.

Hard carbides like Vanadium carbides in steels like S30V and 10V contribute more to edge holding than simple iron carbides in carbon steels or chromium carbides in simple stainless steels. However, they make it more difficult to sharpen, especially when the abrasive in the stones are softer than the carbide. The following is a chart of carbide hardness from Crucible:

HARDENED STEEL • 60/65 HRC
• CHROMIUM CARBIDES • 66/68 HRC
• MOLYBDENUM CARBIDES • 72/77 HRC
• TUNGSTEN CARBIDES • 72/77 HRC
• VANADIUM CARBIDES • 82/84 HRC

More carbides does the same thing. More carbides means more wear resistance, but more difficulty in sharpening. And of course there is the balance of wear resistance with toughness and edge stability that will be covered later.

ajhuff
01-26-2012, 09:36 PM
Is there any difference in performance if the chromium carbides precipitate out as platelets rather than spheres and is that something that can even be controlled with the tempering or is it basically luck of the draw?

-AJ

Larrin
01-26-2012, 09:58 PM
Carbide precipitation in tempering goes through a series of stages. In the early stages of tempering (low temp), fine rows of transition carbides are precipitated within the plates/laths of martensite. They look a little like plates. They are usually not what is described when talking about plate-like carbides. Transition carbides are unlikely to b chromium carbides because chromium is a mch larger atom than carbon and so requires more temperature to precipitate out as transition carbides. At higher temperatures the carbides are spherical. Plate-like carbides are not generally created though tempering. They're more generally associated with certain primary carbides (created during solidification not tempering or other processes of precipitation) or upper bainite.

Hattorichop
01-26-2012, 10:16 PM
Mr. Tanaka's with R2 PM steel is the best performer out of all my knives.

It gets sharper and stays sharper longer then every knife I own.

My kikuichi VG 10's

My Murray Carter White steel

My Itou R2's

My Massakage AS's

My DT AEB-L

My Moritaka blue #2

My Ino white #2

VG 10 Hattori forum I use to own

Takeda AS i use to own

I love my Tanaka!

El Pescador
01-26-2012, 10:17 PM
+1 what Larrin said.

ajhuff
01-26-2012, 10:18 PM
I thought Cr7C3 carbides were spheroidal and Cr23C6 carbides were platelet and that the spheroidal ones came first but I didn't know if that was solid state or during tempering. I may be completely lost though. Thanks.

-AJ

Larrin
01-26-2012, 11:09 PM
I thought Cr7C3 carbides were spheroidal and Cr23C6 carbides were platelet and that the spheroidal ones came first but I didn't know if that was solid state or during tempering. I may be completely lost though. Thanks.

-AJ
It's a difference between primary vs secondary carbides rather than really the type of carbide, though the one type of chromium carbide is more likely to be a primary carbide. There's conflicting literature on which chromium carbide that is.

Mike Davis
01-27-2012, 12:17 AM
This is a fantastic thread!! Thank you Devin for starting it, and thank you to everyone contributing. I loves educating myself on metallurgy.

Eamon Burke
01-28-2012, 01:28 PM
whoa. I am bookmarking this.

DevinT
01-30-2012, 11:24 PM
Toughness is the ability to absorb energy without fracture. (I called Larrin and gave me this definition) In use knives that are too soft will roll at the edge rendering them useless, and knives that are too hard will chip out at the edge or worse break all together and become useless. Proper heat treating is the best way to ensure the best balance of hardness and toughness.

Good toughness in properly heat treated steels will affect other things like edge stability, edge holding, and the sharpenability of the knife. To increase both the toughness and hardness of the steel correct forging and heat treating cycles must be used.

The amount of carbide in the steel and the size of those carbides along with the over all hardness of the steel has the biggest effect on toughness. Some elements added to steels will increase toughness.

Grains in steel are like soap bubbles in a jar. Grains are different than carbides. The smaller the grain and the smaller the carbides in the steel the tougher the steel will be. Correct forging and heat treating of the steel allows proper grain refinement and to a lesser extent smaller carbide size.

Powder metalurgy steels were developed to be able to increase both wear resistance and toughness by reducing both the grain size and the carbide size and by more even distribution of the carbides in the steel.

More to come.

Hoss

Salty dog
01-31-2012, 10:56 AM
BTW Devin, I forgot to ask what steel that twist bar is made of?

DevinT
01-31-2012, 12:06 PM
BTW Devin, I forgot to ask what steel that twist bar is made of?

AEB-L and 302

tk59
01-31-2012, 01:07 PM
BTW Devin, I forgot to ask what steel that twist bar is made of?I take it that means you are going with someone other than Devin to make something out of it.

Salty dog
01-31-2012, 02:04 PM
Yes, no slight to Devin, he seems pretty busy.

JohnnyChance
01-31-2012, 05:10 PM
Yes, no slight to Devin, he seems pretty busy.

Correct, he is busy making knife after knife for TK.

DevinT
02-01-2012, 12:24 AM
Edge stablity, this is the ability for a knife to hold a very fine edge. A fine edge is one that is sharpened to a small angle and to a high grit.

Just like toughness edge stablility is affected most by grain size and carbide size and distribution. Steels with larger carbides and greater volume of carbides are not as stable as ones with smaller and fewer carbides. The smaller the grain the better the edge stability. Pm steels were made to improve edge stability.

There are 2 types of cutting, namely push cutting and slice cutting. Push cutting benefits from finer edges more than slice cutting. Too fine an edge will not work well slice cutting fiberous materials.

The thing that happens to edges that are not stable is that the larger carbides pull out from the edge while in service leaving a flat spot or a hole. This is called carbide pull out.

Kitchen knives, razors, scalpels, axes etc. benefit from greater edge stability.

Proper hardness and the elimination of retained austenite is also beneficial to edge stability.

More to come.

Hoss

ajhuff
02-01-2012, 12:34 AM
I've read in several places this idea of "large" carbides falling out. It seems dubious to my mind. Is there anything out there to support this idea, particularly a photomicrograph?

Thanks,

-AJ

Larrin
02-01-2012, 01:05 PM
I've read in several places this idea of "large" carbides falling out. It seems dubious to my mind. Is there anything out there to support this idea, particularly a photomicrograph?

Thanks,

-AJ
This article on grinding and polishing of tool steels by Buehler mentions carbide pullout: http://www.azom.com/article.aspx?ArticleID=5289

ajhuff
02-01-2012, 01:40 PM
This article on grinding and polishing of tool steels by Buehler mentions carbide pullout: http://www.azom.com/article.aspx?ArticleID=5289

Hmmm.... kind of casually mentions it in passing. In the context of polishing a flat surface, not really the same as a knife edge.

Also, the context I have always read is the "large" carbides pulling out of the knife edge is the pull out is noticeable. How big is a "large" carbide? I still have my doubts.

What I'd like to see is some photomicrographs of a knife edge showing the missing carbides. Actually, I would love to see ANY photomicrographs of some knife edges, especially a transverse view. Are you aware of any Larrin?

Thanks,

-AJ

Larrin
02-01-2012, 05:23 PM
Hmmm.... kind of casually mentions it in passing. In the context of polishing a flat surface, not really the same as a knife edge.

Also, the context I have always read is the "large" carbides pulling out of the knife edge is the pull out is noticeable. How big is a "large" carbide? I still have my doubts.

What I'd like to see is some photomicrographs of a knife edge showing the missing carbides. Actually, I would love to see ANY photomicrographs of some knife edges, especially a transverse view. Are you aware of any Larrin?

Thanks,

-AJ
Since edges are two flat surfaces that meet, I don't see it as being unrelated. Obviously it is a phenomena that is observed.

A large carbide is of course as difficult to define as any other "large" thing. 20 micron+ carbides could probably be classified as large carbides. You're unlikely to notice individual missing carbides, the effect is noticed because carbides tend to cluster, and steels with large carbides tend to also have lots of carbides. You of course wouldn't be likely to observe carbide pullout without going to a fairly polished sharpening.

Here's the first micrograph I could find in my collection. I'll let you come up with your own analysis: http://img845.imageshack.us/img845/2642/bohlern690edge2.png (http://imageshack.us/photo/my-images/845/bohlern690edge2.png/)

Uploaded with ImageShack.us (http://imageshack.us)

Larrin
02-01-2012, 05:29 PM
Here's a picture of some ugly carbides in D2: http://img818.imageshack.us/img818/988/77115254.jpg (http://imageshack.us/photo/my-images/818/77115254.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

ajhuff
02-01-2012, 05:30 PM
Thanks!

-AJ

Larrin
02-01-2012, 05:42 PM
More micrographs! I hope everyone can't get enough of them. Here is showing how carbides effect the radius of an edge with cutting:
http://img854.imageshack.us/img854/5910/13c26knifeedge.th.jpg (http://img854.imageshack.us/i/13c26knifeedge.jpg/)
http://img109.imageshack.us/img109/8639/440cknifeedge.th.jpg (http://img109.imageshack.us/i/440cknifeedge.jpg/)

DevinT
02-01-2012, 05:42 PM
Hmmm.... kind of casually mentions it in passing. In the context of polishing a flat surface, not really the same as a knife edge.

Also, the context I have always read is the "large" carbides pulling out of the knife edge is the pull out is noticeable. How big is a "large" carbide? I still have my doubts.

What I'd like to see is some photomicrographs of a knife edge showing the missing carbides. Actually, I would love to see ANY photomicrographs of some knife edges, especially a transverse view. Are you aware of any Larrin?

Thanks,

-AJ

If you are an avid knife user, you will notice after some use a knife will have some micro chipping which is carbide pull out, at the very least micro cracking that propagates from the carbides at the edge.

This is something that John Verhoeven ( former head of metalurgy at Iowa state) talks about.

Run your knife off the end of your thumbnail and you will get some feed back. Lastly, it's not wise to argue with Larrin.

Look at an edge under magnification and see what you learn.

Hoss

ajhuff
02-01-2012, 05:49 PM
I was only asking questions not arguing. I greatly appreciate the feedback from Larrin.

-Aj

DevinT
02-01-2012, 07:39 PM
More micrographs! I hope everyone can't get enough of them. Here is showing how carbides effect the radius of an edge with cutting:
http://img854.imageshack.us/img854/5910/13c26knifeedge.th.jpg (http://img854.imageshack.us/i/13c26knifeedge.jpg/)
http://img109.imageshack.us/img109/8639/440cknifeedge.th.jpg (http://img109.imageshack.us/i/440cknifeedge.jpg/)

This top photo is of 12c27 and the bottom photo is of 440-C. Ofcourse the 12c27 has better edge stablility.

Hoss

SpikeC
02-01-2012, 09:38 PM
I'm loving this stuff! Great images of what is actually going on.

Eamon Burke
02-01-2012, 09:51 PM
These are so cool! Thanks Larrin!

MadMel
02-02-2012, 06:15 AM
Classic example of a picture speaks a thousand words! Those pics made it much easier to understand!

Salty dog
02-02-2012, 07:34 AM
Since edges are two flat surfaces that meet, I don't see it as being unrelated. Obviously it is a phenomena that is observed.

A large carbide is of course as difficult to define as any other "large" thing. 20 micron+ carbides could probably be classified as large carbides. You're unlikely to notice individual missing carbides, the effect is noticed because carbides tend to cluster, and steels with large carbides tend to also have lots of carbides. You of course wouldn't be likely to observe carbide pullout without going to a fairly polished sharpening.

Here's the first micrograph I could find in my collection. I'll let you come up with your own analysis: http://img845.imageshack.us/img845/2642/bohlern690edge2.png (http://imageshack.us/photo/my-images/845/bohlern690edge2.png/)

Uploaded with ImageShack.us (http://imageshack.us)

I assume that's a cross section of an edge. If so, it sucks to have that vein of rocks right down the middle. Also is that a lefty?

DevinT
02-02-2012, 12:24 PM
That's probably symmetrically sharpened and the photo is cut off at the bottom. The carbides down the middle is a good thing on a hunting knife, but you're right, not on a kitchen knife.

Hoss

DevinT
02-02-2012, 12:56 PM
Sharpenability

The relative ease or difficulty in sharpening a knife.

Several things affect sharpenability. The first is the thickness at the edge, the thinner the edge, the easier it will be to sharpen. There is simply less material to remove.

The size, volume, distribution, and hardness of carbides will affect how easy it is to sharpen. Some carbides, like vanadium carbides, are harder than some abrasives, like aluminum oxide. In such cases it would be necessary to use a harder abrassive to sharpen on to get the keenest edge. The smaller the carbides the easier it is to sharpen. The lower the volume of carbide, the easier it is to sharpen. The more even the distribution of the carbides, the easier it is to sharpen.

The manufacture of the steel has more affect on the carbides than does the forging or heat treating. Grain size to a lesser extent will affect sharpenability. Grain size can be controled by correct forging and heat treating. The smaller the grain the greater ease of sharpening.

Optimal hardness will increase sharpenability. Too hard and the edge will chip out in sharpening, too soft and the edge will roll, even in sharpening.

Burr formation and removal will affect sharpenability. This is controled by hardness and the amount of retained austenite. The elimination of retained austenite will greatly reduce the formation of a burr and will make it easier to remove on sharpening.

More to come.

Hoss

Michael Rader
02-02-2012, 02:30 PM
Thanks guys. Great thread, Devin!!!

-M

DevinT
02-03-2012, 10:13 PM
Stain resistance

the ability for a steel to resist staining, discoloring, rusting, or developing a patina.

Steel composition is the most important for this one. Chrome, nickel, and moly are the main alloying elements when added in sufficient quantities will make steels stainless. To make a steel that is considered stainless it needs to have at least 12% chrome and about 10 1/2% chrome in solution after heat treatment. Nickel in smaller amounts will help stain resistance. Moly actually helps steels against etching.

Heat treating is necessary in making martensitic stainless steels (the ones we make knives out of) fully stainless. In the annealed condition, steels have twice the carbide volume as in the heat treated condition. This is what happens to the carbon and chrome along with other elements in the matrix, it is put into the carbides so that there is very little in the matrix to make it hard. When the steel is heated a certain volume of carbide is desolved and it puts carbon and alloy into the matrix, and then frozen there allowing it to become hard and with enough chrome in the matrix it becomes stainless.

In general, the softer the stainless steel the less stain resistant it is.

The surface finish will also affect the stain resistance of a steel. The finer the finish, or the higher the polish, the more stain resistant it is.

Next we will rate some more popular steels on edge holding, toughness, sharpenability, edge stability, and stain resistance.

More to come.

Hoss

tk59
02-03-2012, 10:31 PM
Thanks, Hoss. I was wondering about the stainlessness. This clears it up a lot for me.

DevinT
02-03-2012, 11:57 PM
Rating some stainless steels.

Steel type Edge holding Toughness Edge stability Sharpenability Stain resistance Overall rating
AEB-L...........6.................4..............10... .............10..................8................ .....7.6
Stainless PM.8..................4..............7.5.......... .....8...................8.5...................7.2
CPM 154.......7.5...............3..............6.5.... ...........7...................8.................. ....6.4
440-C...........7.5...............2..............4.5.. .............7...................8.5.............. .....5.9
VG-10..........6..................3..............6... ...............7...................8.5............ .......6.1
19C27..........6.5...............3.5............6. 5...............7...................7.5........... ........6.2

Some categeries may not be equaly important making the overall rating inaccurate. These numbers are based on our experiance in use and from charts from other researchers. I ran these steels by Larrin and averaged the numbers between us. Others may come up with slightly different numbers, but we feel that these should be close.

More to come.

Hoss

ajhuff
02-04-2012, 12:12 AM
http://s8.postimage.org/4zhdef1vp/chart.jpg

ajhuff
02-04-2012, 12:17 AM
Devin, can you name reference points for some of the categories? For example, it seems you have rated AEB-L as a 10 out of 10 for edge stability with others trailing so it is easy to see what the standard for comparison is. But for toughness it appears that all perform poorly? What is a knife material you would rate as a 10 to put these numbers in perspective? Same for edge holding? Or am I misunderstanding your rating system?

Thanks,

-AJ

DevinT
02-04-2012, 12:24 AM
Rating some carbon steels and tool steels

Steel type Edge holding Toughness Edge stabililty Sharpenability Stain resistance Overall rating
mystery
carbon.......8................4..............8.5.. ...............8...................1.............. .......5.9
super wear
resistant....10..............3..............7..... ...............6...................5.............. .......6.2
white.........5...............3..............8.5.. ................9...................1............. ........5.3
blue super..8...............2..............5........... ..........7.5................2.................... .4.9
O-1...........6...............3.5............8...... ..............8.5.................1.5............. .....5.5
52100........7..............4.5.............9..... ...............9...................2.............. .......6.3

Hoss

DevinT
02-04-2012, 12:33 AM
Devin, can you name reference points for some of the categories? For example, it seems you have rated AEB-L as a 10 out of 10 for edge stability with others trailing so it is easy to see what the standard for comparison is. But for toughness it appears that all perform poorly? What is a knife material you would rate as a 10 to put these numbers in perspective? Same for edge holding? Or am I misunderstanding your rating system?

Thanks,

-AJ

Steels with a 10 rating in toughness would be ones with low hardness like austenitic stainless steels. Tool steels with high toughness would be like S-2 at an 8 and L-6 at a 6. Most tough tool steels have lower carbon levels along with low hardenability.

Edge holding is based on wear resistance. Steels like M-4 are a 9, most knife steels correctly heat treated rate at least a 5. Some of it is based on usable hardness.

Hoss

tk59
02-04-2012, 12:35 AM
I have to say the pm and the mystery carbon are pretty nice to sharpen. I didn't think they were much different than 52100, to be honest. I think 440-C is too high, as well. That should be a 6. :)

DevinT
02-04-2012, 12:41 AM
Some of the numbers are theoretical and will be different in practice depending on skill level, equipment etc.

Thanks

Hoss

mr drinky
02-04-2012, 12:46 AM
Amazing thread guys. It feels like talking knives with Devin and Larrin over a plate of hotdish.

k.

ajhuff
02-04-2012, 12:50 AM
http://s18.postimage.org/hp2b5hd9l/chart2.jpg

DevinT
02-04-2012, 12:57 AM
Thanks AJ for fixing my graphs

Hoss

mr drinky
02-04-2012, 12:59 AM
It is nice that my next two knives are 52100 :)

k.

ajhuff
02-04-2012, 01:00 AM
Thanks AJ for fixing my graphs

Hoss

No problem, happy to help. :D

-AJ

Larrin
02-04-2012, 12:07 PM
It's fun and difficult coming up with the numbers. I've seen similar attempts on bladeforums and Blade Magazine and I always disagreed with the numbers. They're usually by knifemakers who don't know much about steel. At least when I disagree with my own numbers it's not off by 5 points.

tk59
02-04-2012, 12:22 PM
It's fun and difficult coming up with the numbers. I've seen similar attempts on bladeforums and Blade Magazine and I always disagreed with the numbers. They're usually by knifemakers who don't know much about steel. At least when I disagree with my own numbers it's not off by 5 points.I really like these ratings and I like the fact that stainless is separate, since the stain resistance gives stainless steels such a big edge (It looks like 440C is "better" than most carbon steels.).

Larrin
02-04-2012, 12:38 PM
I was really surprised to see how low white and blue super ended up being.

ajhuff
02-04-2012, 12:40 PM
I was really surprised to see how low white and blue super ended up being.

Really? Because of their mythological status? I mean they are really simple steels, nothing out of the ordinary on paper at least.

-AJ

Larrin
02-04-2012, 12:45 PM
Here are the rankings without stain resistance being factored in:
AEB-L 7.5
52100 7.375
mystery carbon 7.125
mystery stainless PM 6.875
super wear resistant 6.5
O1 6.5
white 6.375
CPM-154 6
19C27 5.875
blue super 5.625
VG-10 5.5
440C 5.25

tk59
02-04-2012, 12:46 PM
I was really surprised to see how low white and blue super ended up being.I wasn't too surprised about the white (white 1? if it's white 2 I'd also be surprised since it seems to be tougher and edges more stable) but I did think the wear resistance was higher than I expected on blue super and the sharpenability, edge stability and toughness were lower.

Larrin
02-04-2012, 12:47 PM
Really? Because of their mythological status? I mean they are really simple steels, nothing out of the ordinary on paper at least.

-AJ
I just thought they would have more balance using the pre-determined rating system. I guess it's a good sign that bias is being limited if you're surprised where things end up.

tk59
02-04-2012, 12:50 PM
Here are the rankings without stain resistance being factored in:
AEB-L 7.5
52100 7.375
mystery carbon 7.125
mystery stainless PM 6.875
super wear resistant 6.5
O1 6.5
white 6.375
CPM-154 6
19C27 5.875
blue super 5.625
VG-10 5.5
440C 5.25

That looks like a list we could almost universally agree on, based on experience. I think the pm stainless should be higher though. It sharpens almost like AEB-L but holds a nicer edge longer, at least the way I sharpen and use the knife.

Larrin
02-04-2012, 12:51 PM
I wasn't too surprised about the white (white 1? if it's white 2 I'd also be surprised since it seems to be tougher and edges more stable) but I did think the wear resistance was higher than I expected on blue super and the sharpenability, edge stability and toughness were lower.
It is White #1. Blue Super is one we discussed pretty extensively. It is fairly highly rated by people on the forums but we've never observed any of those touted characteristics in knives we own so that's where its ratings ended up. We tried not to rate things according to hearsay on the forums but tried to stick with our own experience, other's comparative research, and manufacturer's own published information.

Larrin
02-04-2012, 12:52 PM
That looks like a list we could almost universally agree on, based on experience. I think the pm stainless should be higher though. It sharpens almost like AEB-L but holds a nicer edge longer, at least the way I sharpen and use the knife.
With more experience those numbers could change. With the mystery steels some of the numbers are conservative because the feedback has been limited to only a few people and we don't want to get over-excited.

tk59
02-04-2012, 12:53 PM
It is White #1. Blue Super is one we discussed pretty extensively. It is fairly highly rated by people on the forums but we've never observed any of those touted characteristics in knives we own so that's where its ratings ended up. We tried not to rate things according to hearsay on the forums but tried to stick with our own experience, other's comparative research, and manufacturer's own published information.How did you decide to work hardness into the equation?

tk59
02-04-2012, 12:57 PM
...With the mystery steels some of the numbers are conservative because the feedback has been limited to only a few people and we don't want to get over-excited.Yeah, it took me a long time to openly jump on the pm stainless bandwagon. I expected to like AEB-L better just based on ultimate sharpness potential.

Larrin
02-04-2012, 12:58 PM
How did you decide to work hardness into the equation?
Essentially hardness is included in every category, stain resistance being to a lesser extent. The ratings are based on the properties in what we think is the optimal hardness for the steel when used in kitchen knives. Certainly all of them would have higher toughness scores if they were all at 30-40 Rc.

Dave Martell
02-04-2012, 01:12 PM
Something that comes to mind is that I wonder how steels like white, blue, & AS would rate if worked by you guys versus you using these steels as found in Japanese knives?

I wonder this because AEB-L & 52100 rate high as you work them whereas some makers/manufacturers may not fair as well with these steels and could produce inferior results. An example of what I mean is that many people have used AEB-L knives from Japan and report poor edge retention yet so many people use your knives in AEB-L and report great edge retention.

What are your thoughts on this?

DevinT
02-04-2012, 01:17 PM
We have found that with careful forging and heat treating you can make a steel perform a lot better. Heat treating is more difficult than most people think, and takes a lot of practice to get good at it.

Hoss

Candlejack
02-04-2012, 01:20 PM
What's your guys opinion on 12c27?

Larrin
02-04-2012, 01:21 PM
Something that comes to mind is that I wonder how steels like white, blue, & AS would rate if worked by you guys versus you using these steels as found in Japanese knives?

I wonder this because AEB-L & 52100 rate high as you work them whereas some makers/manufacturers may not fair as well with these steels and could produce inferior results. An example of what I mean is that many people have used AEB-L knives from Japan and report poor edge retention yet so many people use your knives in AEB-L and report great edge retention.

What are your thoughts on this?
One easy example is that those AEB-L knives are usually 60 Rc at best, most are 58 or below. For people used to 61+ Rc it's just not going to perform as well. You'll notice we gave AEB-L only a 6 for edge holding, this is primarily a rating of wear resistance as you can see from the definition given earlier in the thread. Edge stability, however, is given a 10. People that use/sharpen their knives to favor edge stability will find the maximum edge holding with their AEB-L knives.

Larrin
02-04-2012, 01:22 PM
What's your guys opinion on 12c27?
12C27 is very similar to AEB-L. 12C27 has lower maximum hardness and wear resistance with a little better stain resistance.

Candlejack
02-04-2012, 01:27 PM
12C27 is very similar to AEB-L. 12C27 has lower maximum hardness and wear resistance with a little better stain resistance.

Yeah, i should clarify: How is your personal feelings about 12c27?

I've heard the AEB-L comparision before. 12c27 is quite a common steel here, cheap and nice. I can get a filet-knife (and i am getting one.. after an unpleasant experiance when i forgot my other filet-knife at home and had to use the schools. It's great to filet flat-fish with what feels like a butter-knife. Took hella time.)

30-40 bucks for a good 12c27 filet-knife is a steal imo.

Larrin
02-04-2012, 01:35 PM
Yeah, i should clarify: How is your personal feelings about 12c27?

I've heard the AEB-L comparision before. 12c27 is quite a common steel here, cheap and nice. I can get a filet-knife (and i am getting one.. after an unpleasant experiance when i forgot my other filet-knife at home and had to use the schools. It's great to filet flat-fish with what feels like a butter-knife. Took hella time.)

30-40 bucks for a good 12c27 filet-knife is a steal imo.
We like AEB-L a lot, 12C27 is very similar, so we like 12C27 too.

tk59
02-04-2012, 01:51 PM
Essentially hardness is included in every category, stain resistance being to a lesser extent. The ratings are based on the properties in what we think is the optimal hardness for the steel when used in kitchen knives. Certainly all of them would have higher toughness scores if they were all at 30-40 Rc.Would it be too much to ask to put the hardness at which each steel was tested on the charts?

tk59
02-04-2012, 01:53 PM
Yeah, i should clarify: How is your personal feelings about 12c27?

I've heard the AEB-L comparision before. 12c27 is quite a common steel here, cheap and nice. I can get a filet-knife (and i am getting one.. after an unpleasant experiance when i forgot my other filet-knife at home and had to use the schools. It's great to filet flat-fish with what feels like a butter-knife. Took hella time.)

30-40 bucks for a good 12c27 filet-knife is a steal imo.

Why use 12c27 if AEB-L is going to hold it's edge a lot longer? It just has less carbon, right? AEB-L is already on low side of carbon content for knives.

Candlejack
02-04-2012, 01:55 PM
Why use 12c27 is AEB-L is going to hold it's edge a lot longer? It just has less carbon, right? AEB-L is already on low side of carbon content for knives.

I kinda just wanted to hear what their experiances with it was. Just out of pure interest as it's a common steel here in Sweden.

DevinT
02-04-2012, 03:14 PM
I bought some 12c27 about 15 years ago or so. I made some kitchen knives out of it that were very thin. It sharpened nice and cut well. I think that AEB-L is a little better.

Hoss

DevinT
02-04-2012, 03:20 PM
Would it be too much to ask to put the hardness at which each steel was tested on the charts?

Most every thing that we have made is in the 62 to 63hrc range. Some knives from other makers have been harder and some softer. We tried to rate steels that we have had sufficient experiance with, wether we made them or from other sources.

Hoss

mhlee
02-04-2012, 05:07 PM
Is the spicy carbon steel that you used recently the same as the mystery carbon steel, or are they different steels?

DevinT
02-04-2012, 05:38 PM
Mystery carbon is an oil hardening steel and the spicy white is a water hardening steel. They are in a different class.

Good question Michael, thanks.

Hoss

tk59
02-04-2012, 05:50 PM
Haha. I think we need something shorter to call all these mystery steels, kinda like what Henckels does. They should be dt-spicy, dt-carbon, dt-pm and dt-super or something of that nature.

Larrin
02-04-2012, 06:45 PM
It's true we do need better names.

mhlee
02-04-2012, 07:01 PM
Thanks Devin.

I'm assuming that since the spicy white is not listed, it does not rank high in your analysis.

+1 to tk's recommendation. For your mystery steels, a "DT" prefix would be a good thing.


Mystery carbon is an oil hardening steel and the spicy white is a water hardening steel. They are in a different class.

Good question Michael, thanks.

Hoss

Johnny.B.Good
02-04-2012, 07:03 PM
+1 to tk's recommendation. For your mystery steels, a "DT" prefix would be a good thing.

+2

Nice and simple.

DevinT
02-04-2012, 08:03 PM
Thanks Devin.

I'm assuming that since the spicy white is not listed, it does not rank high in your analysis.

+1 to tk's recommendation. For your mystery steels, a "DT" prefix would be a good thing.

Spicy white is slightly better than white but would rank the same.

Hoss

El Pescador
02-05-2012, 02:05 AM
I think the mystery carbon should be called Super Judd.

Pesky

Marko Tsourkan
02-06-2012, 10:28 PM
Good stuff Devin.

I might have to help myself (with your permission) to some of the information that I would like to paraphrase and put on my site.

Happy to hear 52100 scored high on your tests.

M

tk59
02-06-2012, 11:20 PM
Super Judd? Uh... Right.

Another thing to keep in mind is the overall ratings are not particularly useful. It's probably a lot more useful to pick a steel based on the purpose. For example, DT-super is likely going to be a better steel than 52100 for making a barbecue slicer out of but 52100 is maybe better for a typical gyuto.

JohnnyChance
02-07-2012, 01:15 AM
Super Judd? Uh... Right.

Another thing to keep in mind is the overall ratings are not particularly useful. It's probably a lot more useful to pick a steel based on the purpose. For example, DT-super is likely going to be a better steel than 52100 for making a barbecue slicer out of but 52100 is maybe better for a typical gyuto.

So what you are saying is...for any application Devin has a steel and heat treat to meet those needs? What a bad bad man.

tk59
02-07-2012, 11:52 AM
So what you are saying is...for any application Devin has a steel and heat treat to meet those needs? What a bad bad man.I'm just saying there are some options here and just because 52100 scores the highest overall, it doesn't mean the other steels aren't worth making knives out of. I don't know if there would be an advantage one way or another but it may be worth considering.

Larrin
02-07-2012, 04:16 PM
So what you are saying is...for any application Devin has a steel and heat treat to meet those needs? What a bad bad man.
Exactly. This is the mistake of many knifemakers. When they have a favorite steel, they think it should be great in any knife they'd like to make.

Vman
02-07-2012, 11:01 PM
Devin,
Love this thread, although a lot to digest. Question, in your opinion which carbon steel common in the market place makes the best all around affordable laser gyuto blade either wa or western hadeled.
Vman

JohnnyChance
02-07-2012, 11:25 PM
Devin,
Love this thread, although a lot to digest. Question, in your opinion which carbon steel common in the market place makes the best all around affordable laser gyuto blade either wa or western hadeled.
Vman

What is your definition of affordable? Usually means a factory knife, and if you are looking for carbon, that means from Japan. And basically all the affordable carbon lasers from Japan are White #2. The Zwilling Bob Kramer line is made of 52100 and those run about $350 for the 10" chef's knife. Takedas are thin and made of Blue Super. Most of the other steels talked about in this thread are used by custom makers.

Larrin
02-07-2012, 11:57 PM
I don't think "affordable laser gyuto" really fits into the steel discussion. That's just a half-step away from a knife recommendation.

JohnnyChance
02-08-2012, 12:22 AM
I don't think "affordable laser gyuto" really fits into the steel discussion. That's just a half-step away from a knife recommendation.

Indeed. Vman, a better place to ask the question and get some recommendations would be in it's own thread in the General>Kitchen Knife section. Plus we won't derail Devin's thread that way.

Vman
02-08-2012, 01:26 AM
My bad, I was enjoying this steel thing so much it got me thinking. Onward and upward
Vman

mpukas
02-11-2012, 04:17 PM
A little late to the party...

Devin - thanks for such an amazing thread! And thanks to Larrin for all of the great info as well. I'm learning so much here. As a blooming knife and sharpening knut, I'm trying to take in and learn as much as I can, and this thread has shed a lot of light on many aspects of steel that I have been pondering.

This thread also touches on many other aspects of knives and sharpening, and I don't want to de-rail this thread (too much), but this quote in particular was great for me;


Lastly, the keener the edge the faster a knife will become dull. The coarser the stone used in sharpening, the longer it will hold that edge. I think that in general most knife nuts over sharpen.

Hoss

I tried to have this discussion on another forum, and I'm not gonna throw anyone under the bus, but I basically got the opposite answer from a couple of diferent sources. It's been my assumpiton that the keener the edge, the more quickly it will dull since the material at the edge is finer. Not that I want to be right or wrong, I just want to understand what's going on. Thanks for this clarification.

I'm gonna copy-paste some of your key posts into a cheat sheet for myself - there's a lot here to digest. I love it! Thanks again for being so open to sharing this info! mpp

DevinT
02-11-2012, 06:05 PM
MPP,

This applies to slice cutting and not to push cutting. Serrations always cut longer than a smooth edge, even on a micro scale.

Serrations cut longer because there is simply more edge, the small radiused scallops measured out, are longer than a straight edge.

The other thing that it does is prevent the whole edge from touching the board for example.

Hoss

eshua
02-12-2012, 03:15 AM
So the downside of an extreme high grit sharpening style is NOT similar to the downsides you see from sharpening too acutely? eg stability?

Lets put it this way... If you have a few prep items that benefit from a really fine edge: getting the thinnest possible scallions basil ect, And later rough up your edge on a ceramic honing rod when you need to bite into tomatoes or grilled meats. Does this work well for you guys or do you end up with an edge just asking to fail when you polish it out too far?

Trying to work though my bad habits one by one so I'm curious to think of the science of it.

DevinT
02-13-2012, 02:20 PM
It is important to match the steel with the heat treatment, sharpening style, cutting habits/preference etc. No one steel or knife can do it all, all the time.

Good edge stability allows for a knife to be sharpened to an acute angle and to a high polish and hold up well. Of course it must have the correct heat treatment also.

Hoss

Andrey_SPb
07-18-2012, 07:08 AM
Devin and Larrin,
Thank you very much for very interesting information!

Let me lay out the summary table ordered by Overall Rating (carbon and tool steels are shown in red):

8676

I'm not surprised by low grades of Japanese steel - White (Shirogami) Steel and Blue (Aogami) Super Steel. But, I first saw the real difference between expressed in figures.
I've always read that the difference between them is absolutely not noticeable in actual use. And your table is clear and significant, and for the most important criteria: Edge Holding = 5 - 8, Edge Stability = 8.5 - 5, respectively.
Thank you. This is very interesting!

The list of steels for the study, you wrote in your first post is a very popular and have become very good - ATS-34, S30V, CPM D2, CPM M4. Could you add a table with the results on these steels?

AEB-L steel was the best in your tests. Do not you think that this is due to the fact that you are working with it for a long time and have learned to “squeeze” the most out of this steel?
And that other knifemakers can not get such good results. On the other hand, they can get the best results on steels, which are working for a long time and which well know and feel?
After all, you do testing knives (!), not steels! For knives, except for steel, are important correct hardening, optimal hardness and good geometry.
That is, I want to say that the steel - not a universal concept. Knives made by different knifemakers of the same steel will show very different results!

In conclusion, I would like to draw your attention to two steel, which seem very promising for the manufacture of kitchen knives - AEB-H and the Cru-Wear. The chemical composition of these steels:

8677

Thank you again for a very interesting and useful thread.
And please do not be hard on my English. :)

Keith Neal
07-18-2012, 10:50 AM
Devin, excellent discussion. Very informative.

Since this is one of your knives, can you tell us about the steel in it?

http://www.kitchenknifeforums.com/showthread.php/6285-for-sale-240-gyuto-sanmai-western-handle

Thanks,

Keith

El Pescador
07-18-2012, 11:12 AM
Devin and Larrin,
Thank you very much for very interesting information!

Let me lay out the summary table ordered by Overall Rating (carbon and tool steels are shown in red):

8676

I'm not surprised by low grades of Japanese steel - White (Shirogami) Steel and Blue (Aogami) Super Steel. But, I first saw the real difference between expressed in figures.
I've always read that the difference between them is absolutely not noticeable in actual use. And your table is clear and significant, and for the most important criteria: Edge Holding = 5 - 8, Edge Stability = 8.5 - 5, respectively.
Thank you. This is very interesting!

The list of steels for the study, you wrote in your first post is a very popular and have become very good - ATS-34, S30V, CPM D2, CPM M4. Could you add a table with the results on these steels?

AEB-L steel was the best in your tests. Do not you think that this is due to the fact that you are working with it for a long time and have learned to “squeeze” the most out of this steel?
And that other knifemakers can not get such good results. On the other hand, they can get the best results on steels, which are working for a long time and which well know and feel?
After all, you do testing knives (!), not steels! For knives, except for steel, are important correct hardening, optimal hardness and good geometry.
That is, I want to say that the steel - not a universal concept. Knives made by different knifemakers of the same steel will show very different results!

In conclusion, I would like to draw your attention to two steel, which seem very promising for the manufacture of kitchen knives - AEB-H and the Cru-Wear. The chemical composition of these steels:

8677

Thank you again for a very interesting and useful thread.
And please do not be hard on my English. :)

I like the idea of your chart but I believe that the data you have used is inconsistent with the results that I have experienced. I have used Devin's 52100 and his mystery carbon side by side and the mystery carbon easily out performs the 52100. They were sharpened the same by the same person. I also think a chart like you have doesn't work because of the inconsistencies in heat treating maker to maker. Taking this further, a maker can vary his heat treat with a certain steel to achieve gains in hardness, toughness or grain size.

Crothcipt
07-18-2012, 12:50 PM
hmm I thought he was just making a chart with what was already posted. Nice addition Andrey spb to the thread.

bieniek
07-18-2012, 01:05 PM
I like the idea of your chart but I believe that the data you have used is inconsistent with the results that I have experienced. I have used Devin's 52100 and his mystery carbon side by side and the mystery carbon easily out performs the 52100. They were sharpened the same by the same person. I also think a chart like you have doesn't work because of the inconsistencies in heat treating maker to maker. Taking this further, a maker can vary his heat treat with a certain steel to achieve gains in hardness, toughness or grain size.

So what you basically say is that DTs heattreatment was optimal for both of those steels - youve tested, and you managed to get the best out of both of them?

Larrin
07-18-2012, 02:31 PM
I'm not surprised by low grades of Japanese steel - White (Shirogami) Steel and Blue (Aogami) Super Steel. But, I first saw the real difference between expressed in figures.
I've always read that the difference between them is absolutely not noticeable in actual use. And your table is clear and significant, and for the most important criteria: Edge Holding = 5 - 8, Edge Stability = 8.5 - 5, respectively.
Thank you. This is very interesting!

The list of steels for the study, you wrote in your first post is a very popular and have become very good - ATS-34, S30V, CPM D2, CPM M4. Could you add a table with the results on these steels?

We'll consider it.


AEB-L steel was the best in your tests. Do not you think that this is due to the fact that you are working with it for a long time and have learned to “squeeze” the most out of this steel?

No. The overall rankings are just a fun thing to look at and are based solely on the categories chosen, different steels should be chosen for different users. The categories were chosen and numbers assigned first, and overall score was simply tabulated. I do not agree in general with most of the "Overall ratings" if they had to be ranked that way. You'll notice that AEB-L has one of the lowest "edge holding" scores listed, there is no inflation here. Sharpenability and edge stability scores are not from squeezing anything out of it but from the small volume of small carbides, and these are supported by tests by Roman Landes and John Verhoeven. Accusations of bias are fine and probably justified, but looking at the numbers again I don't see it for AEB-L. Every number on the chart is arguable, however, and could be changed based on new information.


And that other knifemakers can not get such good results. On the other hand, they can get the best results on steels, which are working for a long time and which well know and feel?

There are ranges of performance for different steels. In general the ratings given are based on what we consider to be the "optimal" heat treatment.


After all, you do testing knives (!), not steels! For knives, except for steel, are important correct hardening, optimal hardness and good geometry.
That is, I want to say that the steel - not a universal concept. Knives made by different knifemakers of the same steel will show very different results!

The ratings are based not only on knife performance but also published information from the steel manufacturers as well as independent tests from other companies or individuals researching steel. Knife designs do not change steel performance, they simply change how the steel performance is being used.


In conclusion, I would like to draw your attention to two steel, which seem very promising for the manufacture of kitchen knives - AEB-H and the Cru-Wear. The chemical composition of these steels:

AEB-H is 19C27. Cru-Wear knives have been made by my father in the past.

El Pescador
07-18-2012, 03:58 PM
So what you basically say is that DTs heattreatment was optimal for both of those steels - youve tested, and you managed to get the best out of both of them?

I don't understand "managed to get the best out of both of them?" can you clarify?

Andrey_SPb
07-20-2012, 05:18 AM
Thank you, Larrin, for the detailed answer.
I will wait with impatience your next publications.

mpukas
07-23-2012, 12:37 PM
Thank you, Larrin, for the detailed answer.
I will wait with impatience your next publications.

+1 !

wsfarrell
07-30-2012, 05:34 PM
Great thread, though a little frustrating that some of the better performing steels are "mystery" steels that have only been experienced by a small handful of forum members. Any plans on making knives with these steels for more general consumption?

DevinT
07-30-2012, 05:44 PM
I apologize for any frustration. I've had a lot of knife makers copy what I use. We've invested a lot in testing and need to hold on to any small advantage that it might bring.

I will use any of those steels in making a knife as long as it fits the task.

Hoss

Chefdog
08-04-2012, 04:07 PM
Devin & Larrin,
Thanks for the information, a great thread all the way through, I thoroughly enjoyed it and learned a lot.
I'd like to second the request to see how some of the air hardening tool steels (A2, D2, 3V) compare to the better carbon and stainless, namely AEB-L & 52100. Thanks again for the contribution.
Jake

DevinT
08-08-2012, 10:48 PM
I've made kitchen knives out of A-2 and 3-V, hunting knives out of D-2. D-2 has high wear resistance but does not make the best kitchen knives due to the fact that it has some of the largest carbides in tool steels. A-2 makes an okay knife, I like several steels better. I have not used 3-V enough to know yet. The knives I have made with 3-V have been in damascus mixed with 154cm.

Hoss

Chefdog
08-09-2012, 12:49 AM
I've made kitchen knives out of A-2 and 3-V, hunting knives out of D-2. D-2 has high wear resistance but does not make the best kitchen knives due to the fact that it has some of the largest carbides in tool steels. A-2 makes an okay knife, I like several steels better. I have not used 3-V enough to know yet. The knives I have made with 3-V have been in damascus mixed with 154cm.

Hoss

Thanks for the input, much appreciated.

oakrockranch
12-29-2012, 06:17 PM
Any thoughts on Cowrey X or ZDP-189? I've had a couple stainless Damascus wrapped Gyutos by Ichiro Hattori utilizing these core steels with great success.

DevinT
12-29-2012, 11:20 PM
They are very wear resistant steels due to to the large carbide volume. The one draw back to these steels is that they are prone to chipping.

Hoss

Mingooch
01-07-2013, 11:36 PM
Devin or Larrin, sorry if this was covered, but I just didnt have time to read all 13 pages right now. Opinion and ranking on R2 like in a Hiro Itou. I know it is one of my favorites at this time, if not my most favorite that I have used.

DevinT
01-08-2013, 12:37 AM
Does anyone have the chemical comp for R2?

Hoss

El Pescador
01-08-2013, 01:02 AM
Larrin wrote this on ITK a couple of years ago

11-23-08 15:47.12 - Post#1693024 ***

****In response to Gator97

R2 and ZDP-189 are in the same class in that they are both going to be high wear resistance powder metallurgy grades. ZDP-189 and Cowry-X are both oddities in that they are stainless steels that can reach extreme hardness (they are the only ones I know of capable of 70+ Rc). R2 could have smaller carbides, as ZDP has a lot of carbide. I would choose between knives instead of steel in this case. If you ever had a choice between the two then I would think about it a little longer.

cclin
01-08-2013, 03:15 AM
Does anyone have the chemical comp for R2?

Hoss

Devin, same as SG-2 steel! R2= SG2....I'll post a new thread explain why!

DevinT
01-08-2013, 12:48 PM
Does anyone have the chemical comp of SG2?

Hoss

El Pescador
01-08-2013, 12:58 PM
SG2= Powdered VG10

Larrin
01-08-2013, 03:25 PM
Gator has this for SG2: http://zknives.com/knives/steels/steelchart.php?snm=SG2

DevinT
01-08-2013, 04:20 PM
It looks like a cousin to S35VN.

Hoss

jmforge
01-08-2013, 04:45 PM
No Niobium.
It looks like a cousin to S35VN.

Hoss

El Pescador
01-08-2013, 05:54 PM
SG2= Powdered VG10

I was wrong SG2 and VG10 are very different composition-wise.

DevinT
01-08-2013, 07:08 PM
No Niobium.

That's why it's a cousin and not a copy.

Hoss

ajhuff
01-08-2013, 10:10 PM
That's why it's a cousin and not a copy.

Hoss

:rofl:

-AJ

Mingooch
01-11-2013, 05:06 PM
So Hoss, how do I get an R2, feather wa-gyuto? LOL

DevinT
01-11-2013, 10:46 PM
So Hoss, how do I get an R2, feather wa-gyuto? LOL

It could be done. S35VN would be very close to or better in performance. S35VN has a little more vandium and a half of one percent niobium, which acts like more vanadium with a little added toughness. S35VN is available here in the US.

Hoss

jmforge
01-13-2013, 06:09 AM
Hoss, what would the advantage be of using PM steel in making damascus? Wouldn't the forge welding process, etc. essentially "unmake" the PM steel?

John Harper
01-13-2013, 09:07 AM
Hi Larrin,



More micrographs! I hope everyone can't get enough of them. Here is showing how carbides effect the radius of an edge with cutting:
http://img854.imageshack.us/img854/5910/13c26knifeedge.th.jpg (http://img854.imageshack.us/i/13c26knifeedge.jpg/)
http://img109.imageshack.us/img109/8639/440cknifeedge.th.jpg (http://img109.imageshack.us/i/440cknifeedge.jpg/)

Great and very informative thread and great photos.

Any idea of the width of the edges shown, in microns?

Cheers
John

DevinT
01-14-2013, 11:33 PM
Hoss, what would the advantage be of using PM steel in making damascus? Wouldn't the forge welding process, etc. essentially "unmake" the PM steel?

In the manufacturing of powder steels they use the HIP process to solidify the billet. After it is a solid piece it is forged like a regular ingot. With careful forging there is no change to the steel for the worse and maybe a slight improvement due to some of the carbides dissolving. The same holds true for making damascus.

Hoss

jmforge
01-15-2013, 12:06 AM
Interesting. so as long as it stays solid, it retains its PM characteristics? I was wondering because you seem to be experimenting with some interesting mixes of PM steels.
In the manufacturing of powder steels they use the HIP process to solidify the billet. After it is a solid piece it is forged like a regular ingot. With careful forging there is no change to the steel for the worse and maybe a slight improvement due to some of the carbides dissolving. The same holds true for making damascus.

Hoss

DevinT
01-15-2013, 11:13 AM
Over heating is the enemy to all steels, PM, cast wrought, damascus etc.

Hoss

Mike Davis
01-15-2013, 03:26 PM
Awesome stuff guys!!! I had no idea you could make powdered steel into damascus, Learn something new everyday. Thanks Devin for leading us into unfamiliar territory :)

cclin
01-15-2013, 07:17 PM
Devin, I can't find any information about your PM stainless. could you compare( Edge holding, Toughness, Edge stability, Sharpenability) between S35VN & DT PM stainless. thanks!!

El Pescador
01-15-2013, 07:37 PM
Devin, I can't find any information about your PM stainless. could you compare( Edge holding, Toughness, Edge stability, Sharpenability) between S35VN & DT PM stainless. thanks!!

who's heat treating the s35vn? need to factor that in too. different heat treatments result in different numbers.

kalaeb
01-15-2013, 07:46 PM
Devin, I can't find any information about your PM stainless. could you compare( Edge holding, Toughness, Edge stability, Sharpenability) between S35VN & DT PM stainless. thanks!!

I have used both and imo can say in edge holding, toughness, and stability,the DT pm stainless wins. On sharpenability they are very similar.

cclin
01-15-2013, 07:54 PM
DT will do the heat treatment for s35vn & PM stainless..

who's heat treating the s35vn? need to factor that in too. different heat treatments result in different numbers.

Sabaki
10-28-2013, 06:31 AM
Rating some stainless steels.

Steel type Edge holding Toughness Edge stability Sharpenability Stain resistance Overall rating
AEB-L...........6.................4..............10... .............10..................8................ .....7.6
Stainless PM.8..................4..............7.5.......... .....8...................8.5...................7.2
CPM 154.......7.5...............3..............6.5.... ...........7...................8.................. ....6.4
440-C...........7.5...............2..............4.5.. .............7...................8.5.............. .....5.9
VG-10..........6..................3..............6... ...............7...................8.5............ .......6.1
19C27..........6.5...............3.5............6. 5...............7...................7.5........... ........6.2

Some categeries may not be equaly important making the overall rating inaccurate. These numbers are based on our experiance in use and from charts from other researchers. I ran these steels by Larrin and averaged the numbers between us. Others may come up with slightly different numbers, but we feel that these should be close.

More to come.

Hoss

This thread is awesome! you make stunning damascus patterns Devin:thumbsup2:
How would you rate 15n20 as a single steel?

Sabaki
10-28-2013, 07:47 AM
Rating some carbon steels and tool steels

Steel type Edge holding Toughness Edge stabililty Sharpenability Stain resistance Overall rating
mystery
carbon.......8................4..............8.5.. ...............8...................1.............. .......5.9
super wear
resistant....10..............3..............7..... ...............6...................5.............. .......6.2
white.........5...............3..............8.5.. ................9...................1............. ........5.3
blue super..8...............2..............5........... ..........7.5................2.................... .4.9
O-1...........6...............3.5............8...... ..............8.5.................1.5............. .....5.5
52100........7..............4.5.............9..... ...............9...................2.............. .......6.3

Hoss

Tried to edit but...:newhere: the 15n20 question should be in this category of course

DevinT
10-28-2013, 10:52 AM
15N20 has good toughness but not very good edge holding compared to other cutlery steels. Toughness=5, edge holding=3.5, edge stability=9, sharpen-ability=9, stain-resistance=2, overall= 5.7

Sabaki
10-28-2013, 01:09 PM
thank you for your answer!

Sabaki
11-03-2013, 05:07 AM
Think i have read somewhere that 15n20 has a 0.11% Cromium content to it, i dont think so but is there?

Is there any difference between 52100 and UHB20c15? if so, do you have a rating as well?


thanks in advance!

JMJones
11-03-2013, 08:13 AM
15n20 is basically 1075 with 2% nickel, it does not have any chromium.

Sabaki
11-12-2013, 12:26 PM
15n20 is basically 1075 with 2% nickel, it does not have any chromium.

I got answer from Bohler-Uddeholm Sweden today, they say it contains 0.11% Cr

DevinT
11-14-2013, 01:39 AM
BU corp buys the stock from more than one supplier and then they roll and process it in to strip and saw blade material. There are some which contain a little chrome and some do not. Chrome is added to refine the grain.

BU corp does make sure that all of its material falls within a very narrow parameter of chemical make up.

Hoss

jgraeff
11-15-2013, 11:24 AM
This is an awesome thread! So much knowledge!

Devin just curious at this point in time which stainless and which carbon would you choose as the best all around guyto steels?

DevinT
11-15-2013, 09:29 PM
AEB-L for stainless and 52100 for carbon always make me happy. My studies right now are on more PM grades along with a few tool steels.
Also, we are doing a bunch of research on heat treatments more than focusing on specific grades of steel.

Hoss

RJD55
11-16-2013, 12:35 PM
Devin - Great thread! Can you give us any insight into how some of the steels like M390 and HAP40 would rate?
Thanks..

CoqaVin
11-16-2013, 12:38 PM
I have heard that HAP40 is quite the steel how come we don't see it being used much?

DevinT
11-16-2013, 02:18 PM
Devin - Great thread! Can you give us any insight into how some of the steels like M390 and HAP40 would rate?
Thanks..

Both are very good steels. They are very expensive and very difficult to heat treat. They both have very good edge holding and are a little on the brittle side. HAP40 is made by Hitachi. I don't think that we can even get that grade here. I'm leaning more towards simpler grades with lower heat treat temperatures that are more readily available.

Hoss

RJD55
11-17-2013, 11:14 AM
Thanks Devin - I've bookmarked this thread and will use it as a reference

CoqaVin
11-17-2013, 11:26 AM
what can be compared to HAP40 as far as wear resistance goes?

RRLOVER
11-17-2013, 12:17 PM
This is an awesome thread! So much knowledge!

Devin just curious at this point in time which stainless and which carbon would you choose as the best all around guyto steels?

That all depends on the "Market".....Is the knife for a knifenut with 15 water stones......Or a budding foodie who has never sharpen a blade.

jgraeff
11-17-2013, 09:27 PM
That all depends on the "Market".....Is the knife for a knifenut with 15 water stones......Or a budding foodie who has never sharpen a blade.

I agree, but still characteristics of the steel are still important. Like edge retention. Toughness, sharpen ability, and level of sharpness achievable.

I'd be looking for a steel that was excellent in all categories.

Also Devon just curious it shows cpm154 as low edge retention but I personally have gotten 1 full month in a pro kitchen with it.. Is this because it's rated around other great steels that it's scored lower? Or did I get an extradionary knife haha

DevinT
11-18-2013, 11:20 AM
We scored it 7.5 out of 10. It scored higher than other stainless steels. There are many stainless steels that are more wear resistant, but that comes at a price. Higher cost, more difficult to work and heat treat, more difficult to sharpen, more prone to chipping, etc. S30-V, S35-V, M390, S90-V, S110-V, S125-V, ELMAX, SG-2, BG-42, 20 CV, are a few that I can think of.

With an excellent heat treatment, CPM 154 is a very good steel to make kitchen knives out of. I am not surprised that it exceeded you expectations. A good steel with a great heat treatment is way better than a great steel with a poor heat treatment.

Hoss

MowgFace
11-18-2013, 11:56 AM
Sent from my iPhone using Tapatalk (http://tapatalk.com/m?id=1)

Sabaki
11-20-2013, 04:26 AM
Wonder about the martensitic transformationdifference in % with and without cryotreatment on AEB-L?
Would it make any difference to put the steel in the freezer -20celcius compared to roomtemperatur?

DevinT
11-20-2013, 11:37 AM
I don't know what the percentage difference would be.
It's best to use a lower austenitizing temperature when a sub-zero quench is not possible. The higher the quench temperature and the longer the soak at temperature, the more retained austenite.

With higher alloy steels the martensite starts to form at around +400'f and finishes at around -60/-90'f. The closer you get to the finish temperature the less retained austenite that you will have.

Hoss

Larrin
11-20-2013, 12:00 PM
I read on a thread recently that AEB-L has more retained austenite than other steels. That is false.

Sabaki
11-20-2013, 02:08 PM
I don't know what the percentage difference would be.
It's best to use a lower austenitizing temperature when a sub-zero quench is not possible. The higher the quench temperature and the longer the soak at temperature, the more retained austenite.

With higher alloy steels the martensite starts to form at around +400'f and finishes at around -60/-90'f. The closer you get to the finish temperature the less retained austenite that you will have.


Hoss

so it will be a small difference but most likely noticeable i guess then?
Thank you for your information!




I read on a thread recently that AEB-L has more retained austenite than other steels. That is false.

Larrin:i guess it is more evenly distributed?

Larrin
11-20-2013, 02:54 PM
Larrin:i guess it is more evenly distributed?
Not that I know of. That's not the point I was trying to make.

Sabaki
11-21-2013, 09:09 AM
Not that I know of. That's not the point I was trying to make.

Think i know what and how you mean, i'm struggling a bit with my english translation:scratchhead:

jgraeff
11-22-2013, 10:58 AM
What is a cryogenic heat treat? And what are the advantages over a traditional method?

bkultra
11-22-2013, 12:14 PM
What is a cryogenic heat treat? And what are the advantages over a traditional method?

http://www.kitchenknifeforums.com/showthread.php/15454-Cryogenic-heat-treatment-and-it-s-importance

Sabaki
01-06-2014, 11:22 AM
I've just ordered a couple A2 flatbars to try out but i wonder if i should have chosen L6 instead?

I guess A2 holds a better edge but L6 is a lot tougher?

El Pescador
01-07-2014, 01:55 AM
Spoke to Hoss and he's got some new steels he's messing around with. Anyone as excited about this as I am?

bkultra
01-07-2014, 09:48 AM
Spoke to Hoss and he's got some new steels he's messing around with. Anyone as excited about this as I am?

Very cool, can't wait to find out more.

jamaster14
02-11-2014, 11:51 AM
This has been an extremely helpful thread... thanks so much for taking the time to put this info together for the forum!

Ruso
07-29-2014, 11:58 PM
This is a great threat. Lots of interesting and detailed information. I wish I would discover it before.
One thing that I have trouble with is the edge stability vs edge holding.
As far as I understand
Edge stability is how of an acute angle the knife can take
Edge holding is how long it will keep the sharp edge (how long it will wear out)
The thing is, how those two correlate? Does that mean that if you put same acute angle on AEB-L and Blue super the Blue super will wear before even though it's edge holding is better?
And vice versa, if you put less of an acute angle Blue Super will last longer then AEB-L??
If the above is correct, are there any data on optimal/best angle ranges for each steel?

menzaremba
07-31-2014, 10:29 PM
Best thread on the site IMHO. I wish we could convince you to do a YouTube series on metallurgy. I'd those money at that kickstarter.

menzaremba
07-31-2014, 11:25 PM
Best thread on the site IMHO. I wish we could convince you to do a YouTube series on metallurgy.