What Kevin and I are reiterating is a general HT mantra:
WITH THESE THREE THINGS YOU CAN MAKE SUPERIOR BLADES
1) know what steel you are using and what final result you desire.
2) understand how to bring those results to fruition in the HT.
3) do everything you can to attain those results.
1) requires having a known steel and knowing what the steel makeup is. Yes it is best to know the exact carbon percentage, but is is imperative that you know the class of steel,too (10XX, A-2, O-1,etc). The difference between 1084 and 1089 is slight, the difference between O-1 and 1089 is huge (but they are closer in carbon % than 1084/1089).A basic understanding of the alloys in steel will help with steel selection, and understanding how the alloy will affect HT.
2) requires some basic metallurgy knowledge, the understanding of what is happening in HT, and how to make different things happen. This understanding will eliminate the often quoted," I read on one site that you just heat it up to........" ,and not having any idea whether that will really work or not. If you understand carbon solution (just enough to know what it basically is), you will understand soak times. If you understand what Austenite is and at what temperatures it forms and converts, you will understand the HT temperatures and quenching better. If you understand what happens when the austenite cools and how martensite forms, you will be able to temper properly. (Note: most smiths temper way too low)
3) requires caring enough to never say, " Well, that will be good enough....", or, " If it doesn't harden right, it will be good practice." You may not know if it is good enough until it fails, you may not know if it hardened right or not!
Learning the entire HT process, from anneal to temper (and all the steps along the way) is crucial to making a good knife. Regardless of your skill at forging/grinding, regardless of your equipment,......the complete HT process, done right, is where a piece of pretty steel becomes a functional knife.
These understandings will not make all knives alike, and won't make all knife makers do things the same. What they will do is allow the maker to achieve the desired goal with assurance and repeatability.
Kevin understands the superiority of differentially tempered Martensite (drawing the spine on a fully quenched blade).
I understand the beauty of pearlite invading martensite ( a hamon from a clay coated quench).
We both understand the limits and reasons for these things, and where they are appropriate, and where they are not. It won't stop me from quenching some knives with clay coated blades. But, I will know why Kevin speaks in favor of fully martensitic blades.
Phillip:
The difference between 1084 and Aldo's high assay 1084 ,at .89% C, is that he has allowed for some carbon loss in forging, thus he is selling "forging steel". When the steel is forged, fully annealed, ground, normalized,and austenitized.... then it will be about .84%C when it is ready for the quench.
Stacy
lol ... i just need to know how much it will hurt the knife.
