chris freeman Posted January 23, 2019 Share Posted January 23, 2019 I've been using canola oil for years now. I've not had many problems except for recently. I have been trying to get a big bowie knife quenched. I forged it out of leaf spring. It would not harden. At least with a file check. The file seemed to dig in every time. I tried 3 or 4 times. Finally I tried water. The file seemed to dig even still but it warped my blade. I tried to straighten it and it broke. The broken ends were very crystallized. I guess it hardened. But why didn't the file skate off? Any help is appreciated. Thanks, Chris Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 23, 2019 Share Posted January 23, 2019 Excessive decarb layer? The coarse crystallization sounds like overheating it. Did you normalize it before hardening? Quote Link to comment Share on other sites More sharing options...
chris freeman Posted January 23, 2019 Author Share Posted January 23, 2019 9 hours ago, ThomasPowers said: yes I did normalize it. I brought it up to critical temp then reduced it to just under and quenched. I didn't think I over heated it. They weren't course crystals. they were actually very fine. I actually probably heated it too many times during the forging process. I bet I did get excessive decarb from that. Quote Link to comment Share on other sites More sharing options...
Daswulf Posted January 23, 2019 Share Posted January 23, 2019 I could be wrong but I'd think that even somewhat rancid oil would work where needed in quenching. Sounds like possible bad steel. Quote Link to comment Share on other sites More sharing options...
swedefiddle Posted January 23, 2019 Share Posted January 23, 2019 Good Morning, Chris From what you have stated above, you didn't allow the piece to "normalize" or "anneal". You quenched it. More Lessons please. Life Lessons. The School of Hard Knocks, is in session. Neil Quote Link to comment Share on other sites More sharing options...
basher Posted January 23, 2019 Share Posted January 23, 2019 not all leaf springs are hardenable, some of the stack may well be mild steel. if it was a single spring its most likly to be a carbon steel. canola does slow down over time/ use as it oxidises so needs to be refreshed every now and then mine lasts a year or so. Quote Link to comment Share on other sites More sharing options...
chris freeman Posted January 23, 2019 Author Share Posted January 23, 2019 10 hours ago, swedefiddle said: Good Morning, Chris From what you have stated above, you didn't allow the piece to "normalize" or "anneal". You quenched it. More Lessons please. Life Lessons. The School of Hard Knocks, is in session. Neil Neil, As I did state in the first or second post, I did normalize. 3 heats. I truly think it decarbed because of too many heats. I guess from the way I worded it it sounds like that. I ment to say, I normalized 3x then brought it back up to temp and quenched. Thanks though. Quote Link to comment Share on other sites More sharing options...
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