Posted 14 August 2007 - 10:49 AM
Posted 14 August 2007 - 01:01 PM
But, if that's the sole heat treatment regimen alone, then it remains a confusing process with no clear defined role in the improvement of the blade. It's being done, because someone said to do it, or your teacher did it that way. It's not done because you've thought this through for yourself, or tried experimenting with several of your favorite steels to see what works for you, given your shop tools.
Thermal cycling, multiple normalizing cycles, triple quenching are names for essentially the same process: grain refinement. The reason three keeps coming up all the time is that after about three cycles, there is no further benefit in grain reduction when compared to the amount of grain growth from a fourth heating cycle. However, there continues to be misapplication of the name of the process and continued misunderstanding of what the process actually provides the maker. Grain refinement can improve the heat treatment character of a blade. It can improve hardness to some degree, improve the toughness and fracture resistance of the steel, and provide a known starting point for a regular, consistent heat treatment regimen that will promote a consistent product.
Each steel has a temperature range that will respond better to this practice.
Posted 22 August 2007 - 06:02 PM
Good luck with it!
Christopher Price, Bladesmith
Posted 23 August 2007 - 06:35 AM
Ed is using a Oxy Acetylene set up and heating only the working portion of the blade with FLAME for NOT long soak times. Part of his process includes the gradual and repeated pulling of carbides into "solution" and three times helps achieve this.
If you are using an oven and can SOAK 5160 and 52100 for 20 minutes to pull all of the carbon and chromium loose prior to a good DUNK in the proper oil, a triple quench is not necessary.
Edited by kbaknife, 23 August 2007 - 06:36 AM.
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