How far up the blade do you let the oil get on an edge quench? I did an edge quench half way up the blade, then etched it and my quench line ran diagonal at about a 45dg. I thought the quench line would follow the oil line but it did not. Any thoughts on why?
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edge quench
- Thread starter DanL
- Start date
- Joined
- Jun 10, 2001
- Messages
- 1,385
Ya what he said!
Did you get it into the oil fast enough?
Did you get it into the oil fast enough?
- Joined
- Oct 16, 2001
- Messages
- 1,917
As for depth of quench, that is up to you, the maker. You can adjust each individual blade in terms of toughness/flexibility vs. hardness/strength by varying the depth of quench. It all depends on your intended purpose for the individual piece. Form follows function.
As for oil depth vs. hardening depth, that depends on a couple of things as well. First is the steel you are using. 5160, 52100, or L6 all might harden slightly above the oil line as they have longer windows to drop from critical to below @900F. 1095 might harden slightly below the oil as it must drop to below @900 in around one second. In both cases this also depends on cross sectional geometry and depth of quench. A very shallow quench, say 1/4 of the blades width, will likely produce fairly close correspondence between oil line and hardening line. But if you quench higher up the blade, and if your cross sectional geometry is somewhat thick (usually not a good thing), their is a chance the blade will retain heat and not fully harden. This, of course, is more of a problem with 1095 and other steels with which you need a near immediate temperature drop. A final variable here is original heat. Are you heating the entire blade or just the edge? Are you sure all portions of the blade being quenched are at critical when you quench?
The hardening line you mention sounds like one of three possible things: portions of the blade never reached critical and so were not at critical going into the quench; portions of the blade cooled to below critical between the forge (salt pot?) and the quench; you quenched tip (or choil) first and waited too long to quench the other portion.
Also be sure your oil is preheated to between 120-160, otherwise it is too viscous to effectively remove heat from your blade. (There are other ways to quench with the oil at around 400F, but they are a bit more complicated and many oils will flame up on you long before they hit 400.).
John
As for oil depth vs. hardening depth, that depends on a couple of things as well. First is the steel you are using. 5160, 52100, or L6 all might harden slightly above the oil line as they have longer windows to drop from critical to below @900F. 1095 might harden slightly below the oil as it must drop to below @900 in around one second. In both cases this also depends on cross sectional geometry and depth of quench. A very shallow quench, say 1/4 of the blades width, will likely produce fairly close correspondence between oil line and hardening line. But if you quench higher up the blade, and if your cross sectional geometry is somewhat thick (usually not a good thing), their is a chance the blade will retain heat and not fully harden. This, of course, is more of a problem with 1095 and other steels with which you need a near immediate temperature drop. A final variable here is original heat. Are you heating the entire blade or just the edge? Are you sure all portions of the blade being quenched are at critical when you quench?
The hardening line you mention sounds like one of three possible things: portions of the blade never reached critical and so were not at critical going into the quench; portions of the blade cooled to below critical between the forge (salt pot?) and the quench; you quenched tip (or choil) first and waited too long to quench the other portion.
Also be sure your oil is preheated to between 120-160, otherwise it is too viscous to effectively remove heat from your blade. (There are other ways to quench with the oil at around 400F, but they are a bit more complicated and many oils will flame up on you long before they hit 400.).
John
- Joined
- May 20, 2000
- Messages
- 198
I have had good luck heating whole blade and quenching whole blade for about two seconds. Then I raise about 1/3 of the blade up out of the oil for another couple of seconds. Last I raise blade again so only the final 1/3 remains in the oil to totally harden. This leaves enough heat in the spine to keep it a bit softer while blade becomes harder toward the edge.
The blade is 1/8" x1" 52100, the edge was 1/32" thick. It was quenched tip first. Oil was at 150dg F. This blade was triple quenched, 1st at 1/2"deep oil,2nd at 5/8" deep/ 3rd at 3/4" deep. These were done 24 hours apart. To me it looks like the 3/4" oil pulled the heat out of the whole blade and caused the whole blade to harden. It was not tempered in between quenchings. Tempered at 385dgs 3x 2hours each. This blade did good on the 2x4 chop then shaves hair.
- Joined
- Oct 16, 2001
- Messages
- 1,917
I think you are right--if your blade is one inch wide and you quenched to 3/4" there is a good chance that it hardened all the way through. 5160 and 52100, perhaps due to the chromium but don't quote me, tend to be "deep hardening." I don't know if they are classified as deep hardening steels, but they do have a long window to drop below 900F. Two ways to cure this: quench shallower or only heat the portion of the blade you wish to harden.
John
John