SLD Steel. Any good?

[HappyamateurDK]

Hi all.

I can see SLD semi stainless is used by several makers, some of them are also pretty high priced. I just bought a Kaeru myself but it's too early to make a verdict.

But what do you guys think about SLD? Is it any good? And are there reasons why other stainless/semi stainless seems to be used more?

Have a nice day

 

[Blumbo]

I’m becoming a big fan of the steel! My personal experience is that it takes a more aggressive edge off high grit stones than some of the common stainless steels like vg10 and ginsan, and doesn’t really rust/patina at all. In general it seems like the heat treat of sld is pretty hard relative to other options, and it seems to keep a keener edge for pretty long.

 

[Qapla']

SLD is one of the variants of D2 tool-steel. It's a high-chromium semistainless steel. (There are also fully-stainless variants such as R2/SG2.)

https://zknives.com/knives/steels/steelgraph.php?nm=D2, SLD, SKD11, SRS13, SG2

 

[Justinv]

The knocks on D2 is its large grained, lacks toughness, and is not easy to sharpen. The PM versions should be much better and probably a solid choice of steel. I have never tried D2 but I would avoid the non-PM conventional variant.

 

[captaincaed]

I ingot D2 is one of my least favorite steels to sharpen and use. I've not tried PM D2, but have heard it is an improvement.

The other steels in that chart are PM, and considerably nicer steels to live with.

Worth noting SLD apparently is more of a brand name that applies to SKD11, which is a more technical term. I'm not sure of the nuance here but they're often used interchangeably on the forum.

SKD 13 is equivalent to A2, and a joy to use.

 

[bill_zeng]

The knocks on D2 is its large grained, lacks toughness, and is not easy to sharpen. The PM versions should be much better and probably a solid choice of steel. I have never tried D2 but I would avoid the non-PM conventional variant.

HI

High-quality D2 steel, with a hardness of HRC 60, has better edge impact resistance compared to VG10 and SG2 at the same hardness.
The benefit of its difficulty in sharpening is that the edge retention is excellent.
I'm not sure if coarse grain structure is present in all D2 steel, but based on my experience, D2 is relatively difficult to sharpen to a very sharp edge at a large bevel angle. However, if the edge angle is reduced to within 15°, a D2 steel blade can still be sharpened easily enough to cut hair with a light touch. Additionally, at a smaller edge angle, D2 steel is more durable and less prone to chipping compared to VG10 and SG2.

 

[bill_zeng]

HI
SLD (D2) steel, being a very old type of steel, has a very mature heat treatment process. D2 steel, with a hardness around HRC 60, is an excellent material for kitchen knives.

However, when the hardness exceeds HRC 62, the impact resistance of D2 steel becomes as brittle as that of SG2 and VG10.

D2 steel is not considered very tough among tool steels. However, compared to commonly used steels like VG10, AUS10, and SG2, D2 steel's edge impact resistance is not inferior. Additionally, it is more wear-resistant and its cutting feel is closer to that of carbon steel.


Sharpening can be an issue, but it's not difficult if you use common Japanese synthetic whetstones. If you use diamond sharpening stones, the process is very simple, at least when using high-quality sharpening stones.

I use CHOSERA 400 grit, Suehiro 1000 grit, and Shapton 5000 grit stones, along with a leather strop treated with KOYO K1 polishing compound.

It's a bit harder to sharpen than regular stainless steel, but much easier than powder steels（M390 S110V ZDP189 ）.

 

[jedy617]

Hmm from the data I've seen, sg2 is tougher than D2. I have had D2 chip on me a few times before, but never sg2.

 

[bill_zeng]

Hmm from the data I've seen, sg2 is tougher than D2. I have had D2 chip on me a few times before, but never sg2.

This still depends on the hardness and edge angle. I most frequently use SG2, with one knife from Tojiro and another from Sakai Takayuki.
The hardness of the Tojiro is slightly lower, while the Sakai Takayuki is around 62 HRC.
Under the same 10° edge angle in daily use, SG2 often develops many chips, whereas D2 at HRC 60 does not. Of course, D2 is a general term for a class of steel, while SG2 is a brand name. The quality of D2 can vary between different manufacturers.

 

[jedy617]

Hmm not sure if I buy that, SG2 has a much finer grain structure, and Dr. Larrin Thomas's data shows SG2 being tougher in testing...unless you really have some insane special D2. Not sure most ingot D2 has a ton of relevance today besides very budget knives ($50 or lower).

 

[bill_zeng]

Hmm not sure if I buy that, SG2 has a much finer grain structure, and Dr. Larrin Thomas's data shows SG2 being tougher in testing...unless you really have some insane special D2. Not sure most ingot D2 has a ton of relevance today besides very budget knives ($50 or lower).

SG2 does indeed have a very fine grain structure. However, SG2 with a hardness of 62 at a 10° edge angle has lower edge strength compared to D2 at a hardness of 60. In a few days, when I have time, I'll make a video comparing SG2 and D2 cutting through fish bones and chicken wing bones.

 

[sumis]

SG2 does indeed have a very fine grain structure. However, SG2 with a hardness of 62 at a 10° edge angle has lower edge strength compared to D2 at a hardness of 60. In a few days, when I have time, I'll make a video comparing SG2 and D2 cutting through fish bones and chicken wing bones.

would love to see this. thanks for the trouble!

shouldn't heat treat and maker be taken into consideration here, rather than comparing charts? at least for an end user, comparing SKD11 with SG2 makes most sense on a case by case basis.

for instance, i have a Nihei SLD knife that's supposedly taken to over 65 hrc. i wouldn't split a lobster with it, but in my use it's less prone to chipping than any of my SG2 knives, sharpens easily enough, touches up super easy, holds its edge impressively long, doesn't really oxidise, and has a very'carbonish' feel in general.

i know less about heat treatments and stuff than most guys here has forgotten, but i feel the question if SKD11 is good or bad seems makes only partial sense for an end user.

.

 

[jedy617]

sld or skd? skd is tough

 

[azn_knives_4l]

would love to see this. thanks for the trouble!

shouldn't heat treat and maker be taken into consideration here, rather than comparing charts? at least for a end user, comparing SKD11 with SG2 makes most sense on a case by case basis.

for instance, i have a Nihei SLD knife that's supposedly taken to over 65 hrc. i wouldn't split a lobster with it, but in my use it's less prone to chipping than any of my SG2 knives, sharpens easily enough, touches up super easy, holds its edge impressively long, doesn't really oxidise, and has a very'carbonish' feel in general.

i know less about heat treatments and stuff than most guys here has forgotten, but i feel the question if SKD11 is good or bad seems makes only partial sense for an end user.

.

Yeh. Fun to try and compare different steel in a vacuum but it's very often not meaningful.

 

[bill_zeng]

sld or skd? skd is tough

1.5% C
1% V
12% CR
0.8% MO
0.3% MN

 

[Redwax]

Geometry matters most. Then probably heat treatment. SLD aka SKD11 & D2 has reasonable to maybe slightly subpar toughness, mediocre to passable corrosion resistance and rather good wear resistance for an ingot steel generally speaking but again the grind and thickness will be more important than all of that.

It would be more relevant to compare specific knives rather than alloys. eg. it doesn't make sense to compare the toughness or likelihood of chips between a workhorse in SLD and say a Takemura in SG2. The alloy is a very minor factor in that case.

My 2c: it's a pretty good allround steel. Generally better than a lot of the basic steels, not quite in the same league as most of the powder steels. Some people don't like it, but if sharpened properly it performs very well.

 

[romanjanos]

would love to see this. thanks for the trouble!

shouldn't heat treat and maker be taken into consideration here, rather than comparing charts? at least for an end user, comparing SKD11 with SG2 makes most sense on a case by case basis.

for instance, i have a Nihei SLD knife that's supposedly taken to over 65 hrc. i wouldn't split a lobster with it, but in my use it's less prone to chipping than any of my SG2 knives, sharpens easily enough, touches up super easy, holds its edge impressively long, doesn't really oxidise, and has a very'carbonish' feel in general.

i know less about heat treatments and stuff than most guys here has forgotten, but i feel the question if SKD11 is good or bad seems makes only partial sense for an end user.

.

I have same in konosuke madei sumiiro version. It's better than any of my sg2 (yu kurosaki, nigara)

Sld (skd11) 65+ rockwell

(The suji is skd(12) yoshikane)

 

[Troopah_Knives]

Just, to clarify D2/SLD does not have a coarse grain structure, but rather coarse carbides.

 

[azn_knives_4l]

Just, to clarify D2/SLD does not have a coarse grain structure, but rather coarse carbides.

Fing *yuge* carbides. Enough to outperform even S90V on some tests.

 

[Troopah_Knives]

Fing *yuge* carbides. Enough to outperform even S90V on some tests.

Yup, that's what happens in high alloy ingot steels. Even many lower alloy steels gave larger carbides then S90V.

 

[Troopah_Knives]

SG2 does indeed have a very fine grain structure. However, SG2 with a hardness of 62 at a 10° edge angle has lower edge strength compared to D2 at a hardness of 60. In a few days, when I have time, I'll make a video comparing SG2 and D2 cutting through fish bones and chicken wing bones.

Usually, the reason we care about hardness is because it is highly correlated with the yield strength of steels. Yield strength and hardness can diverge somewhat but I'd be surprised if that were true in this instance, especially considering the similar carbide volumes in these steels. But I'd be interested to see your testing methods.

 

[bill_zeng]

Usually, the reason we care about hardness is because it is highly correlated with the yield strength of steels. Yield strength and hardness can diverge somewhat but I'd be surprised if that were true in this instance, especially considering the similar carbide volumes in these steels. But I'd be interested to see your testing methods.

A simple testing method is to use the same edge angle to cut through chicken wing bones. For a gyuto, cutting through chicken wing bones might be the most severe usage condition encountered in proper use. I didn't use a 10-degree edge angle because I didn't want to cause too much damage to the SG2 knife. Instead, I increased the edge angle to 15 degrees. This angle is sharp enough and also sufficient to cause damage to SG2.

 

[MSicardCutlery]

We may not be taking into consideration a potentially important variable here. Larrin's micrographs were likely not taken on D2 that had been forged as a kitchen knife may be. Consequently the toughness of D2 knives may in fact be greater than his testing indicated. I doubt forged conventional D2 outperforms PM D2, but it could potentially be an influential variable in this case.

On top of that....are we certain that the Japanese SlD/SKD11 is produced via ingot and not spray form or PM process? Personally I doubt that it would be, but I think it's worth being certain of our basic presumptions before the debate goes very far.

I like CPM-D2. It has similar edge retention to MagnaCut while being easier to finish and sharpen on conventional stones.

 

[Troopah_Knives]

We may not be taking into consideration a potentially important variable here. Larrin's micrographs were likely not taken on D2 that had been forged as a kitchen knife may be. Consequently the toughness of D2 knives may in fact be greater than his testing indicated. I doubt forged conventional D2 outperforms PM D2, but it could potentially be an influential variable in this case.

On top of that....are we certain that the Japanese SlD/SKD11 is produced via ingot and not spray form or PM process? Personally I doubt that it would be, but I think it's worth being certain of our basic presumptions before the debate goes very far.

I like CPM-D2. It has similar edge retention to MagnaCut while being easier to finish and sharpen on conventional stones.

As far as I know, SKD 11 is ingot steel. Which is consistent with the considerable banding visible in the steel.

I would be quite surprised if forging D2 increases the toughness measurably given the relatively low amount of deformation that occurs in comparison to the reduction that occurs from forging the initial ingot down into bars. Larrins testing of the effects of layer thickness on toughness showed relatively modest toughness improvements even with very large changes in layer width.

 

[parbaked]

I use a Kaeru and Konosuke GS+ regularly.
In my experience, with those knives, the steel is tough, cuts well for a long time and sharpens easily on my Shapton Pro stones.
I like it a lot.
I remember when JNS launched the Kaeru line and posted this video:
Kaeru v chicken bones

 

[Cliff]

I'm not that rough with it, but that's the knife I travel with. It loves BBW. Feels much more confidence inspiring than my Yoshi SKD, which can split atoms just by pointing in their direction.

 

[HumbleHomeCook]

A simple testing method is to use the same edge angle to cut through chicken wing bones. For a gyuto, cutting through chicken wing bones might be the most severe usage condition encountered in proper use. I didn't use a 10-degree edge angle because I didn't want to cause too much damage to the SG2 knife. Instead, I increased the edge angle to 15 degrees. This angle is sharp enough and also sufficient to cause damage to SG2.

With all due respect, why in the world would one do this and in what realm would it be considered "proper use"?

EDIT TO CLARIFY: With a gyuto.

 

[parbaked]

With all due respect, why in the world would one do this and in what realm would it be considered "proper use"?

That is how one cuts chicken when cooking proper Chinese food. You want chunks of bone in each bite sized piece. It’s considered tastier.

 

[HumbleHomeCook]

That is how one cuts chicken when cooking proper Chinese food. You want chunks of bone in each bite sized piece. It’s considered tastier.

Understood, thank you. Sorry, I meant why would I do this with my gyuto. I use a thicker-edged cleaver but I wouldn't use any of my gyutos.

 

[azn_knives_4l]

That is how one cuts chicken when cooking proper Chinese food. You want chunks of bone in each bite sized piece. It’s considered tastier.

This but also the simple fact that it's a test and testing is ineffective unless it achieves adequate stratification of results. CATRA studies are performed on silica cards, too, with different protocols even for serrated knives because they're so different from plain edge.