Chris Waldon Posted May 1, 2009 Share Posted May 1, 2009 In the many posts showing new knives for critique, I keep seeing comments like "nice temper line" I don't know if I'm blind or what, but could someone show me what a temper line is and how it is made. Thanks in advance Quote Link to comment Share on other sites More sharing options...
johnptc Posted May 1, 2009 Share Posted May 1, 2009 (edited) In the many posts showing new knives for critique, I keep seeing comments like "nice temper line" I don't know if I'm blind or what, but could someone show me what a temper line is and how it is made. Thanks in advance often called a temper line but its not. it is usually the result of a differential heat treat by covering the spine and part of the blade with mud prior to heat treat. the line shows up between the hard martensite edge and the pearlite formed in the mud covered area which does not quench quickly enough to become martensite. see http://www.waltersorrells.com/blades/gallery.htm for pics Edited May 1, 2009 by johnptc Quote Link to comment Share on other sites More sharing options...
Ecart Posted May 2, 2009 Share Posted May 2, 2009 Anything special about the mud? I'm maybe 30 minutes from Chris and I live in the middle of red clay heaven. Could I just coat the spine and part of the blade with some red clay, or does anything need to be added? Or is red clay totally unsuitable for this purpose?" Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted May 2, 2009 Share Posted May 2, 2009 search using the term Hamon, we have a few links explaining this. including these two.http://www.iforgeiron.com/forum/f14/differential-heat-treat-chat-9579/http://www.iforgeiron.com/forum/f52/japanese-heat-treat-clay-mix-4613/ Quote Link to comment Share on other sites More sharing options...
Ecart Posted May 2, 2009 Share Posted May 2, 2009 Thanks for those links Steve. I should have known it has been discussed and simply searched for it myself. I'll have to try a differential temper soon. Quote Link to comment Share on other sites More sharing options...
johnptc Posted May 2, 2009 Share Posted May 2, 2009 Thanks for those links Steve. I should have known it has been discussed and simply searched for it myself. I'll have to try a differential temper soon. it is really a differential heat treat........the hamon is created at the time of quench. the tempering only makes the hamon fade a little i am not sure where the term temper line came from.......:confused::confused: Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted May 2, 2009 Share Posted May 2, 2009 (edited) What part of the information in the links was not clear about differential hardening? Please let me know so I can clarify in the sticky so others are not confused about this. I also have differential tempered blades, and it is not the same process, and I saw no noticeable difference in the etching from it. I do understand that many people don't understand the difference between harden and temper, Sadly even some smiths, remember the TV commercials all the rage about Tempered steel blades in razors.. also a tempering is needed after any hardening operation for stress relief if nothing else. Edited May 2, 2009 by steve sells typos Quote Link to comment Share on other sites More sharing options...
new guy Posted May 2, 2009 Share Posted May 2, 2009 this is a very useful thread. thanks for starting and commenting on this. i think this will be very useful for furture smithing ventures. Quote Link to comment Share on other sites More sharing options...
Ecart Posted May 3, 2009 Share Posted May 3, 2009 Steve, being new to the process I just want to make sure I'm clear on this. I may try it next week on a couple of hand seax-ish blades that I have ready for HT. This is what I plan to try: Heat treat: Heat to nonmagnetic and quench in veg oil as it is all I have. Temper: Reheat to nonmagnetic then quench the edge only- for how long? Am I on the right track here? If you were to differential harden then how would you temper? Maybe in a toaster at say 400 degrees? I may try one blade with a differential heat treat, and the other with a differential temper to see which works best for me. I don't think it is a matter of something being unclear in the sticky. I think it is a matter that I am too new to the process to completely understand without asking more questions and trying it myself. Quote Link to comment Share on other sites More sharing options...
Ed Steinkirchner Posted May 3, 2009 Share Posted May 3, 2009 the way that i have gotten lines on my blade edges is to heat evenly to non-mag(after normalizing) and quench the edge in oil. don't leave scratches across the blade as the stress could break it during quenching. then etch in, well, anything acidic enough, or just keep it as is and eventually you will see it. P.S. it is only a hammon if clay is used on the spine, otherwise i considder it a quench line Quote Link to comment Share on other sites More sharing options...
Ed Steinkirchner Posted May 3, 2009 Share Posted May 3, 2009 Dang, forgot to tell how long...quench till spine has no glow in low light, and plunge the rest in. Quote Link to comment Share on other sites More sharing options...
Ecart Posted May 3, 2009 Share Posted May 3, 2009 I was going to patiently wait for a time period. Lord knows I forget my share of things lately. Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted May 3, 2009 Share Posted May 3, 2009 (edited) Steve, being new to the process I just want to make sure I'm clear on this. I may try it next week on a couple of hand seax-ish blades that I have ready for HT. This is what I plan to try: Heat treat: Heat to nonmagnetic and quench in veg oil as it is all I have. Temper: Reheat to nonmagnetic then quench the edge only- for how long? Am I on the right track here? NO, first the entire process is a heat treat, as it is using heat to change the structure of the steel. You started correctly, but then got a bit off in details heat to non magnetic then allow to cool slowly, this normalizing. Then heat again to non mag and cooling fast quench is the hardening part. tempering is relaxing the steel as its very brittle after a hardening, even a differential, it does not magical make it less stressful for the steel. I covered this in the sticky, but here we go again... if using clay that holds in the heat, slowing the cooling of the area covered, thats why we cover the spine and not the cutting edge. Using an Edge only quench is closer with out the fancy pattern in the line of demarcation. is cools what is in the liquid, and the spine being out of the quench cools a bit slower. in both cases, it should leave a line where the martensite and perlite meet. Tempering is only heating to a low temp to relax the stress of the steel, How hot that is will effect the hardness of the steel also, I cant give y ou exact temps with out knowing the exact steel you are using. but most simple steels 530F is plenty. if you heated it again to non mag it will cause another transformation into austenite then ouy are back to the begining again. Edited May 3, 2009 by steve sells Quote Link to comment Share on other sites More sharing options...
Ecart Posted May 3, 2009 Share Posted May 3, 2009 Ya, I don't know why I thought I should reheat to nonmag after heat treat. I understand normalizing and I had planned to do that, but without me saying so specifically in the other post, you had no way of knowing that. I understand normalizing better than any of the rest of the process as I do it on a regular basis when welding bandsaw blades at work. Okay, so after some final prep on the two blades in question, I think I'll try it next week. Quote Link to comment Share on other sites More sharing options...
Chris Waldon Posted May 3, 2009 Author Share Posted May 3, 2009 Ok, so I read the links you posted steve, and I still have a few questions. like Ecart, I'm new enough that it doesn't instantly make sense to me. What exactly is a hamon? is it the same thing as a temper line? For small knives, is it practical to use this process since they will never be exposed to the forces that would cause them to need a soft spine? I didn't see anyone answer Ecart's earlier question about red clay. we both live in red clay city, so can you use that for the "mud." Thanks for your help so far though guys =) Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted May 3, 2009 Share Posted May 3, 2009 its the line between between the hard martensite edge and the perlite spine areas as for red clay. I don't think the blade cares much about what color your clay is, its like me asking you what is better: green or blue ? its a open ended things without any information to base the answer on, all I can say is try it. whats it gonna hurt? Quote Link to comment Share on other sites More sharing options...
Chris Waldon Posted May 3, 2009 Author Share Posted May 3, 2009 Thank you Steve. As for the "red" clay, I didn't mean that the color was significant, just the iron oxide composition. I was wondering whether anyone (like you) had tried it. Thank you all for your help Quote Link to comment Share on other sites More sharing options...
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