Stacy E. Apelt - Bladesmith
ilmarinen - MODERATOR
Moderator
Knifemaker / Craftsman / Service Provider
- Joined
- Aug 20, 2004
- Messages
- 38,255
Thanks Larin for the detailed explanation.
Shqxk,
What the general consensus of those I have discussed this subject with is this:
You have to force steel to become bainite. It doesn't go there willingly, and if given any leeway, it will change to something else. This means that in a thing like a knife, the actual structures attained are only theoretical, and without high level metallurgical analysis it is not known what exact structures are in the blade. Add to that that the next blade may be slightly different. The equipment is specialized, and the time frame is both long and critical. The average knifemaker could not do this HT.
In normal blade HT, there are three basic structures to be dealt with - they all start with austenite. The transition is into either pearlite or martensite. With martensite, the structure is not difficult to form, and the blade is reliably predictable as to the amounts of other structures. The process can be done by nearly any maker with reliable results ... and in a reasonable time frame.The hardness and toughness results are also very predictable with a proper HT.
The "advantage" of a bainite blade is 99% in the structure name and 1% in any higher attribute. In actual real world performance the bainite and martensite blades would be rated the same.
It is sort of like the argument between attaining 3% RA and 0% RA, yes one technically is superior, but the actual amount of gain may never be observable to the user.
There is no really good or compelling reason to form bainite in a knife blade instead of tempered martensite ... other than to say, "I did it!".
Shqxk,
What the general consensus of those I have discussed this subject with is this:
You have to force steel to become bainite. It doesn't go there willingly, and if given any leeway, it will change to something else. This means that in a thing like a knife, the actual structures attained are only theoretical, and without high level metallurgical analysis it is not known what exact structures are in the blade. Add to that that the next blade may be slightly different. The equipment is specialized, and the time frame is both long and critical. The average knifemaker could not do this HT.
In normal blade HT, there are three basic structures to be dealt with - they all start with austenite. The transition is into either pearlite or martensite. With martensite, the structure is not difficult to form, and the blade is reliably predictable as to the amounts of other structures. The process can be done by nearly any maker with reliable results ... and in a reasonable time frame.The hardness and toughness results are also very predictable with a proper HT.
The "advantage" of a bainite blade is 99% in the structure name and 1% in any higher attribute. In actual real world performance the bainite and martensite blades would be rated the same.
It is sort of like the argument between attaining 3% RA and 0% RA, yes one technically is superior, but the actual amount of gain may never be observable to the user.
There is no really good or compelling reason to form bainite in a knife blade instead of tempered martensite ... other than to say, "I did it!".
