overmodulated Posted July 26, 2009 Share Posted July 26, 2009 Folks: I've only quenched about a dozen blades of various steels types before, but one thing is already becoming apparent to me which I haven't seen in written this bluntly before.... please let me know whether you concur or if I'm off base with this thinking:There is a direct relationship between how hard your edge ends up being and how much risk you're willing to take by inadvertantly destroying it. Stated differently, if you go the safest routes during quenching, you typically end up with somewhat less hardness than that steel is capable of attaining. Take the biggest gamble, and any high carbon blade potentially achieves its greatest level of hardness. This is at least how I'm seeing it. Did I oversimplify the tradeoff to be made here? Thanks for sharing your experience and knowledge of this process. Quote Link to comment Share on other sites More sharing options...
kbaknife Posted July 26, 2009 Share Posted July 26, 2009 There is absolutely NO gamble in achieving full potential hardness in steel - the steel industry does it every day. Full hardness is achieved by using known steel, with proper maintenance of specific heats in a controlled atmosphere, and utilizing the proper quenching methods to achieve full martensite formation. Probably one of the least mentioned aspects of what we do in knife making, and the one that induces the greatest strength to the steel is pinning the grain size prior to a controlled austenizing cycle. One needs to invest the time to acquire the knowlege and experience, as well as the proper accumulation of the right tools and even simple equipment to repeatedly obtain the most complete formation of martensite that one can get. I do everything I possibly can to get my chosen steels as hard as they can be. NOTHING is tougher than properly tempered martensite. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 27, 2009 Share Posted July 27, 2009 You can always leave the edge a bit thicker and go for max hardness and then after tempering grind it the rest of the way down. A thin edge can be a problem in HT. Quote Link to comment Share on other sites More sharing options...
overmodulated Posted July 28, 2009 Author Share Posted July 28, 2009 I didn't realize that a little thicker blade increases the probability of success during quenching! Quote Link to comment Share on other sites More sharing options...
kbaknife Posted July 28, 2009 Share Posted July 28, 2009 I didn't realize that a little thicker blade increases the probability of success during quenching! It doesn't increase the probability of success during quenching. It may, however, DECREASE the possibility of failure. The thinner sections can over heat VERY quickly, experience EXTREME grain growth when exposed to extreme heat, and suffer from radical cooling rates when so many people use quenchants that were designed for auto transmissions, or for cooking french fries. Irregular grinding practices, along with failure to stress relieve during post-and pre-forging phases, can cause irregular cooling rates and cause warpage. By leaving edges thicker, this extra material can help to resist deformation during the creation of martensite. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted July 28, 2009 Share Posted July 28, 2009 Well even back several hundred years ago the proverb was "if a good blade you would win; you forge thick and grind thin" Quote Link to comment Share on other sites More sharing options...
kbaknife Posted July 28, 2009 Share Posted July 28, 2009 If you've done a good job pinning your grain size, thermal cycling your steel post-forging, and don't over heat your steel, .030" is about perfect for hardening if you use the proper quenchant. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.