What is this? (Polishing/etching metallurgy question with pics)

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Kippington

Kippington

A small green parrot
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I'm polishing up a 1095 mono-steel blade and there's a funky wood-grain look going on above the hamon. It doesn't show up on the hardened steel yet the whole blade has been etched and polished in the same way. I tried both ferric chloride and hot vinegar etches and it happens the same. The effect is really subtle and hard to pick up on camera.

Has anyone seen this on other mono-steel knives? What's going on metallurgically? It reminds me of the appearance of wrought iron cladding, but obviously that's not the case here.

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looks a bit like banding/clouds. I have a honyaki with similar pattern on the hamon, just more pronounced.
 
i like it like this...no need for any more work :)
 
labor of love said:
Another workhorse?
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Kinda, I was told to make whatever I wanted and this is how it turned out without a plan. The heel looks thick but it distal tapers fast.

I appreciate that a lot of you think this effect looks cool and I should leave it (and I will out of pure laziness, I've spent long enough getting it to this stage!), however I'd still love to know if this sort of appearance has a name, or what it looks like on other blades done with polishers that know more about what they're doing.

I'd assume this is what alloy banding looks like, but part of my heat-treat is done specifically to remove banding (normalize higher at 900°C then cool faster than air to above A[SUB]R[/SUB]1 and in air to black before doing a standard normalize), so I'd love to count that out if possible.

valgard said:
looks a bit like banding/clouds. I have a honyaki with similar pattern on the hamon, just more pronounced.
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The description of 'clouds' cracks me up - It's so hard to work out the terminology on hamons when every part of it looks like a cloud!
Not having a jab at you of course, only at the vernacular that surrounds the topic.

Have you got a picture of the one you say has a similar pattern? I'd love to compare the two.
 
There was a really interesting thread not too long ago about banding, with some cool (but way over my head) contributions by Dan P, I'll try and find it...
 
I'm there alright. :biggrin:

The thread is about alloy banding which I believe I understand well enough (maybe not?) to think that it's not the case here.

For example, from that thread:
DevinT said:
Carbides in simple carbon steels will all dissolve at ~1650-1700f...
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This knife is made from a simple carbon steel (1095) which was soaked at over 1650°F for 10 mins and had a fast cooling rate as part of it's HT. That should be enough to eliminate most alloy banding from my understanding - unless the bar stock was in terrible condition. However, patterns of some kind still come out in the etch. Maybe the cause is something else?

At any rate I personally don't want any alloy banding in my knives, no matter how sweet it looks! Good thing it doesn't show up in the hardened part of the blade.
 
1095 is hypereutectic steel and so it has undissolved carbides in austenitic phase. On top of that I have seen this kind if banding reported with hypoeutectic steels too. It might also be related to impurities (I think). We need our steel nerd (I mean - expert [emoji56]) Larrin to give it a closer look :)
 
Kippington you should not be allowed to post cool knife pics if you aren’t accepting orders at the moment 😀. And yes, that is the butthurt talking.
 
valgard said:
Jules, this is much more exaggerated than yours but it's the one I have. I'm willing to bet it's the same just a finer figure/segregation.
View attachment 39323
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YES! That's exactly what I'm wondering about. Does this phenomenon have a name? And what causes it? I can guarantee that it has nothing to do with clay because mine never used any.

It's good to see other makers getting the same thing, I was worried I was doing something wrong. :laugh:

labor of love said:
Kippington you should not be allowed to post cool knife pics if you aren’t accepting orders at the moment 😀. And yes, that is the butthurt talking.
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Haha! I hope your passaround gets back to you soon, you can check out Marek's knife too.
 
Jacob_x said:
Yeah sorry not to assume you aren't plenty knowledgable about banding...
Just watched your birdy day out vid, that little guy rocks!
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I appreciate the help anyway. :)
Birdy was a legend. Unfortunately he was kidnapped a few months ago. I miss the little bugger. :(
I'm training up a new one in his place.
 
Jules, as far as I know that’s called banding, personally have never seen another name for it. I don’t think you need to make such a big deal out of it TBH, gonna look cool AF and probably won’t have any noticeable impact on performance. But that’s just my opinion.
 
It gives me the dreaded feeling that something is out of my control in the heat-treat. I don't know what the cause is! HNNNGGGG...

Hey, you're probably right. I'll try to chill out a bit and enjoy it as a 'quirk'. It's finished and in the mail anyway, there's nothing else to do about it.

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Hey...

i would like to think that it is present on the whole blade.

on the hardened area.. it takes more patience to coax it out with intermittent sessions of removing oxides and wiping it with mild acid till satisfied. BTW, i have always thought that that etching is a western or a "Ninja" way to raise the patterns on the blade (if any) which is so common on an old sword and its manifestations is a testament of the bladesmiths skill as to bladesmithing and playing with fire. I came across a section where a traditional sword polisher uses nitric acid .. ratio 1:100 to coax out whatever patterns on the steel.... not just the hamon...

Have fun
 
Thanks man!

zitangy said:
I came across a section where a traditional sword polisher uses nitric acid .. ratio 1:100 to coax out whatever patterns on the steel.... not just the hamon...
Click to expand...
Very cool, I was not aware they did anything like that.
 
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