thunderforge777 Posted October 7, 2014 Share Posted October 7, 2014 i keep having the problem of my forged blades breaking because of large grain. i made some that were good and some that broke. its hit or miss. i know because every one that breaks i look at it and see the grain. today i forged a blade from an old nicholson file and it broke in the oil quench. a chunk of it came off and i could see the grain. i try not to keep them in the fire for very long when i forge them, as little as possible. i normalize 3 times before hardening then tempering. is it the crappy steel files or is it something im doing wrong? Quote Link to comment Share on other sites More sharing options...
metalmangeler Posted October 7, 2014 Share Posted October 7, 2014 When normalizing just go up to temp. do not hold temp and do not go beyond temp. try the same thing on your quench, try on scrap. Then break and check for grain growth. I would try to work these problems out before you heat treat knives otherwise the knives are not really worth much. experiment on scrap. you need to have a uniform steel supply, most of the time scrap steel come in too small quantities to be really get the best out of it it costs to much in R&D to really be worth while. Now if you are just making a few knives for fun and quallity is not really that important then making then from cast off files should be fine. Still I would want to heat treat some scrap to a level I was happy with before I did a knife that was prone to problems. Quote Link to comment Share on other sites More sharing options...
basher Posted October 7, 2014 Share Posted October 7, 2014 what is your normalising process, what method are you using to judge temp?? If you are overheating during the normalising or the heat for hardening its going to cause grain growth. Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted October 7, 2014 Share Posted October 7, 2014 Do a stock removal knife, then heat treat. Did the problem persist in this un-forged blade? If so your procedure is wrong for normalization/heat treat. Are you following good forge theory? That is to start hot and end cool. Are you overheating during forging? These are all questions you'll have to work out. Also, one other thing, did you remove the teeth on the file before forging? Some don't but I found that the teeth will get pushed into the steel and can cause stress risers that can cause the steel to break. This could have been the reason it broke in the quench, that or overheating. Quote Link to comment Share on other sites More sharing options...
Frank Turley Posted October 8, 2014 Share Posted October 8, 2014 Try to do all your heat treating on the rising heat. Don't overheat and let air cool to the "proper temperature" or you will retain some large grain. Quote Link to comment Share on other sites More sharing options...
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