Wrought Iron Farm Posted July 20, 2014 Share Posted July 20, 2014 I'm having a hard time hardening my steel. I'm a glass blower so I have an electrics kiln that I use for glass and now heat treating. I set my digital pyrometer to 1575 and when it hit 1200 I put the blades in. I let it hit 1575 and tested the magnativity of the blades and there was none. I took out the first blade after letting it soak for 10 mins then quenched in oil and let sit till cool. Did the same with blade two. I tried to file it to check hardness and the file cut right thru. So I take it it didn't work? Any help would be appreciated. Thanks Also it was 5/32 x 2" x 8" long Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted July 20, 2014 Share Posted July 20, 2014 What kind of oil did you use? Quote Link to comment Share on other sites More sharing options...
Wrought Iron Farm Posted July 20, 2014 Author Share Posted July 20, 2014 Vegetable Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted July 20, 2014 Share Posted July 20, 2014 Decarburization layer? Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted July 20, 2014 Share Posted July 20, 2014 I've had issues with veg oil not fully hardening. Canola is supposed to be better, I use Parks 50 now. Check the back of the blade, if your edge is thin and your procedure is a little slow the edge can cool down and not fully harden. I'm assuming you are not forging your blades, but if you are, long forging sessions can cause decarborization. Sometimes the only way to see what's going on is to break it. The grain of the steel will tell. Quote Link to comment Share on other sites More sharing options...
Wrought Iron Farm Posted July 20, 2014 Author Share Posted July 20, 2014 Yes there was a carbon layer on the blade. I don't forge my own blades I get admiral steel 1095cra. Quote Link to comment Share on other sites More sharing options...
Wrought Iron Farm Posted July 20, 2014 Author Share Posted July 20, 2014 Should I reheat and quench again? I don't want to just give up on this one it's one of my best so far. Quote Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted July 20, 2014 Share Posted July 20, 2014 Try water and see what it does on a test piece. Curious why you wait to put them in. All of the heat treating I have done was starting with the items in a cold oven, then heating to temp. Quote Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted July 20, 2014 Share Posted July 20, 2014 You can mitigate scaling with various coatings. Quote Link to comment Share on other sites More sharing options...
Wrought Iron Farm Posted July 20, 2014 Author Share Posted July 20, 2014 I read somewhere online that said put it the kiln around 1200. I have been looking for it and can't find it now of course. It might have been a YouTube video now that I think about it. So I should put it in cold and bring up to temp? Also can I reheat this knife? Quote Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted July 21, 2014 Share Posted July 21, 2014 Yes, you can re-heat treat the blade. Use a test piece first to get the method down, then do your blade. Quote Link to comment Share on other sites More sharing options...
Wrought Iron Farm Posted July 21, 2014 Author Share Posted July 21, 2014 I went for it and used my torch this time and quenched in oil. It's hard XXXXXX now the file just passed right over it. But now the blade is warped it has a slight bow to it. I was going to do two cycles at 425 and try to straighten it after second heating? I appreciate the help btw guys Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted July 21, 2014 Share Posted July 21, 2014 If you know how to do a soft back draw, temper then do the draw. It will be a little easier to straiten, but work it while at tempering temps. If you've never had to straiten a blade, there are many methods. I just put mine in the vice and use my twisting wrench to tweak them. Quote Link to comment Share on other sites More sharing options...
homeshow Posted August 21, 2014 Share Posted August 21, 2014 If you know how to do a soft back draw, temper then do the draw. It will be a little easier to straiten, but work it while at tempering temps. If you've never had to straiten a blade, there are many methods. I just put mine in the vice and use my twisting wrench to tweak them. I tweak with a vice and twisting wrench. Quench for .10 seconds, check the edge and spine for straight Quickly quick. Then back into the quench oil. Cool completely then straight into the toaster oven. Quote Link to comment Share on other sites More sharing options...
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