gold heat treat

B

blademakr

Joined
Jan 3, 2007
Messages
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I'm hoping one of you can help me. A few months ago I sent 14 blades to a new (for me) heat treater. Of coarse I looked at his referances and spoke to him personally. My expertise, if you can call it that, is making knives, I obviously have limited knowledge on heat treating. I sent him 6 -154cm and 8-d2, the blades came back gold in color, the 154 blades were mottled and the d2 blades were perfectly gold. I of course immediatly phoned him and he said the color was from the near perfect vacuum process he uses and assured me that each blade was tested and were 59 to 61 RC as I had requested. I just don't feel good about finishing these blades and possibly selling them. I should also say that I'm use to the purple/black color that my blades came back as from two other west coast treaters. Anyway, I'm hoping one of you came help me with this question. Thanks, Rich
 
Bronze/golden sounds about perfect to me. That is how my S30V blades come back, it is from the vacuum. I have never seen them any other color. In fact, if they wern't Bronze/golden that would indicate a leak in the vacuum furnace and would have to possibly be re-run. Finish them up, they'll be just fine.
 
Well.......if you dont trust the guy.......why did you send you blades to him in the first place???


Take one out, finish it, and put it to the test.
 
If you are worried about it, find someone to hardness test it.
I'd look for a local heat treater and if there is none, start checking with better machine shops.
It'll take 'em 2 seconds to tell you what you've got.
 
A little history,started out 30 years ago in Calif. finishing knives ground by Bob Engnath,ended up him showing me how to grind my own, even though it took business from him,what a great guy, I think of him often. I moved to Mich. started using Mike Sakmar (Mokume expert) another great guy, he didn't do nitrrogen, so I tried Knife and Gun, they didn't do individual testing and I wanted someone closer so I went to Peters. Anyway, my blades always came back purple/black, thus when they came back gold a flag went up. As far as why did I try him in the first place, how do you know if you don't, also let me say that I didn't say it was wrong, just differant and I was concerned. Thank You " all" for responding, I really appreciate your knowledge and advise. Rich
 
I send plenty of CPM-154 to Brad at Peters'. They are plate quenched and cooled with N2 spray then cryo'd. The cryo gives them the mottled look. Then after cryo and temper, they get the gold tinge. I have never had any issues with any of my blades except for slight pitting which they have since corrected in their process.
 
i had a d2 blade heat treated and it came back with the same gold color you're talking about. the blade was just fine and i wish the color would have stayed but a few passes on the belt sander took care of the color. just finish up the blade and use it.
 
this colour chart has nothing to do with vaccum heat treat
this chart refers to carbon steel heatet in air
if you are doing vaccum proces there should be no air and no colours,
unless a vaccum furnance is leaking and little air gets inside, so then you can have very different colours depending on how many air gets inside the furnance and what was temperature of the blade at the moment
blademakr said:
(...) the color was from the near perfect vacuum process (...)
Click to expand...
near perfect vaccum - little air inside the furnance ;)
 
Your blades are fine. In fact gold is better color than the purple you were getting.
The gold ones will be have a higher rockwell then the purple ones.
Black ones is big time leak so no one can tell how they turned out unless you rockwell test them.
 
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