tempered martensite or bainite?
I have been reading quite a bit lately and it seems a better option is quenching down to a temp above the martensite formation temp and holding there to get bainite to form...it is just as hard and a lot tougher, plus it requires no post quench temper.

Does anyone here try for bainite. I watched the albion "sword making" video on youtube and it appears that their blades are not tempered martensite, but bainite as they quench in a salt bath.

Has anyone here cross-sectioned a blade they've made and checked the hardness throughout. I imagine there are more than a few people fooling themselves about structure as the quench times to get pure martensite are very quick, and even a thin blade probably has a good amount of pearlite in the center due to the lower cooling rate at center.

No offense to anyone...for sure, I am just realizing after reading that it's not as easy as: cherry red hot, quench, straw temper, done.

Even in an industrial setting, the quench can produce a fair amount of pearlite and ferrite.

Thanks again for all the info. Love the site.
Re: tempered martensite or bainite?
Jake Wilson wrote:
I have been reading quite a bit lately and it seems a better option is quenching down to a temp above the martensite formation temp and holding there to get bainite to form...it is just as hard and a lot tougher, plus it requires no post quench temper.

I agree. it is right.



Jake Wilson wrote:
Does anyone here try for bainite. I watched the albion "sword making" video on youtube and it appears that their blades are not tempered martensite, but bainite as they quench in a salt bath.


I have not seen the video, I do not know how to temper use in Albion. But cool in a bath of salts does not mean a bainitic tempering.



Jake Wilson wrote:
Has anyone here cross-sectioned a blade they've made and checked the hardness throughout. I imagine there are more than a few people fooling themselves about structure as the quench times to get pure martensite are very quick, and even a thin blade probably has a good amount of pearlite in the center due to the lower cooling rate at center.

No offense to anyone...for sure, I am just realizing after reading that it's not as easy as: cherry red hot, quench, straw temper, done.

Even in an industrial setting, the quench can produce a fair amount of pearlite and ferrite.


I agree if we refer to pieces of larger dimensions. But the swords were already very small. The transformation of martensite, reaches high levels, when the section is small.
Usually prefer the bainitic tempering when the pieces are of complex shape. When you want to avoid deformations. Can certainly be the case with the swords. You lose just a bit of resistance. This is obviously a very general discussion, the goal should always be assessed one wants to achieve.
I am guessing you would need a rather warm (near 400 F) "mar-quench" using an alloy for which this is appropriate, followed by a lengthy tempering. Salt baths are the norm for the heating, quenching, and tempering. It is no small thing to attempt at home with improvised equipment. There have been others who have posted here in the past about this type of heat treat, and expressed preference for mixed phases of bainite and martensite together. I doubt you would have much chance of succeeding at getting either in a pure homogenous phase.

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