Possible Heat treat issue

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J. Hoffman

J. Hoffman

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Jan 1, 2011
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I just got some blades back from heat treat, and I noticed that some of the blades ,after soaking in vinegar to help remove the scale, appear to have a metal flake paint appearance. This could not be seen prior to soaking them. The other blades have dull finish like I've seen before (only my third batch of knives from heat treat). I was sure that all of the blades were 1095, but now I'm wondering if I screwed up and had some that may have been 1084. If the 1084 were heat treated as if it were 1095 would it create that metal flake look? Thanks for any help.
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the heat treat for 1084 and 1095 are pretty much the same except 1095 has a faster quench. If a faster quench were used on 1084 it should not effect the ht. Check with the shop to see what quench oil they used. I believe the metal flake look you see is decarb which is common with carbon steel. Under the right conditions the decarb can be minimized but it happens. Typically you leave carbon steel blade a bit thicker so after HT you can grind down to good steel.
 
While 1095 and 1084 are different steels and do require different heat treating processes, you still probably got a useable blade, just not ideal. I suggest you do a simple file skate test to see if you got a hardened blade....if so, go ahead and sand off the scale and finish the knives. ( I am assuing the blades were also tempered). If you are sure you made a mistake, it might be wise to re-heat treat using the proper process. In any event, if these are knives for a customer, you need to re-heat treat to be sure you got the right process for the right steel. I do not know if treating 1084 as 1095 would cause the flaked appearance you are seeing but maybe someone with experience in this will chime in. Good luck !
 
Thanks much. I was pretty sure that the blades were all 1095, but I wasn't sure after I saw the different finishes on some of the blades. They cleaned up good.
 
You are just seeing the artifacts of HT. It can vary a lot. Sand them down, and it will almost surely disappear.
 
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