lines or cracks after heat treat?

I'm pretty sure that anti scaling compounds can deliver contaminants to the steel or screw it up. You might want to check on that.
 
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Yea Tai I think your right. Especially if the steel was way over heated. I will do some testing on a clean bar to see if thee is any visible problem. If it is contaminated steel it should show up fairly easy. But I really think it was a problem of severe overheating.
 
Brian, if the steel was from the last of a batch there May have been a quality control problem in which slag or other contaminants were left in the steel. This is very rare though.
 
I think the guys have figured out the possible problems.

I had skimmed this thread and thought, could he be using 1095? Sure enough, yes... I wonder if your supplier sent you the wrong steel and they fast quenched a slow quench steel? This is a wild guess...

I have heard bad stuff about a major supplier of 1095, mixed up batches, bad alloy banding, just garbage steel. Who knows, it could be rumor.
 
I think certain types of contamination might screw with the grain,... but you'd have to check on that.

... might not be from overheating.
 
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Thanks Avigil..I will contact him on monday..He was a great guy to deal with, thats why this is surprising. I'm thinking maybe he has someone under him who does the heat treating. I don't know, I guess I'll find out Monday!
 
When I first started to make knives I used a forge for heat treat. I didn't have a way to heat my quench oil so I started using a piece of O1 steel I had laying around. I would put it in the forge and when it got cherry red or hotter I would pull it out and use it to heat my quench oil along with a thermometer I had in the oil. Anyway I used the O1 over an over and it started to resemble what your pictures look like but worse. So I am betting it cooked like several others.
 
J. Hoover said:
When I first started to make knives I used a forge for heat treat. I didn't have a way to heat my quench oil so I started using a piece of O1 steel I had laying around. I would put it in the forge and when it got cherry red or hotter I would pull it out and use it to heat my quench oil along with a thermometer I had in the oil. Anyway I used the O1 over an over and it started to resemble what your pictures look like but worse. So I am betting it cooked like several others.
Click to expand...

I used a piece of 5160 for the same purpose and saw the same thing after it had been used a lot. I also saw a similar pattern once on a blade that had been over-heated a few times and then water-quenched, but they were much less severe and did not show up until the blade was etched.
 
Look at the colors and oxide patterns on those blades,... very atypical. I suspect something else is going on which may have to do with some type of anti scaling coating if used and/or some type of contamination.

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I've never seen iron oxide (high temp., or otherwise) look like that. Although oxides aren’t usually considered a problem in and of themselves, they can give us clues into the steel. This looks very strange to me. Add the weird oxide colors/patterns together with the surface texture, strange crack formation, large grain and you have a really odd looking piece of material.
 
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If it wasn’t for the atypical oxide colors and patterns, I would think that it was just fried. However, to me they seem to suggest some type of metallic impurities or contamination. I never have used any anti scaling compound, so I don’t really know what that is supposed to look like post HT, but I doubt it's supposed to look like that.
 
If I saw a piece of metal like the knife pictured above while I was out prospecting I might think some Copper was nearby.

(lol super wild guesses now! :D )
 
Some of the colors do suggest copper,... blue, turquoise. I thought that too. Copper contamination can really mess up a piece of steel. You can check for it by leaving it in acid, usually a few days, but depending how strong the solution is. If there is copper in it it will come out copper plated.

Of, course they do add very small amounts of copper to certain alloys, but not 1095.

The color blue is also associated with cobalt. "Cobalt-60" is what they found in some radioactive steel.
 
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I have seen similiar colors on blades wrapped in foil packets for heat treating when a small piece of wood or paper was included in the packet. No cracks or spiderwebbing on those blades were not cooked they were properly heat treated for the steel. Temps exceeded 1900 degrees with hold time of 30-45 minutes.

I have tried anti-scaling compound on some 1095 blades. What I got was a clean blade after heat treat when heated to normal approved temps. What I did not get was the RC I was looking for. Still have some of the stuff in the shop, maybe I'll coat a piece of scrap and run the temps up to 1850 or so with soak just to see what comes out.
 
I've seen some similar splotchy colors on air hardening blades heat treated in stainless foil, but not crusty, thick, and opaque like that... case hardening colors are also "similar", the most similar I've ever seen.

Thick crusty oxides on steel/iron are typically red or black.

I think some type of chemical reaction from a coating is a possibility. Colors like that are often associated with salts and different metals.

I'm curious to hear what it turns out to be.
 
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