Good post Pichou. Now I understand more of what you're saying. I would never have thought to use lead at 800c. to austenize. Other than obvious health hazzards, that would work beautifully. Now days, molten salts do that job with much more safety. However, to do a 300c. temper would require an alloyed lead to get the melt temp lower than pure lead, and the Sheffield razors would have been quite soft at that temper, compared to what most expect a razor hardness to be today. I do think the Sheffield would get the job done, but it would require more attention to keep it sharp. Also, I'm sure you are aware that the lead bath is not what gives the blade it's hardness, it is the quench that would be done at that temp. As you pointed out, the lead, or salt bath gives a very even, and deep heat, with no decarb, or scale until it is quenched. Very good. Thanks. You've got me wondering if they were possibly making the steel into Bainite, which process was developed in the 1920's, or 30's, I believe. Maybe a bit later. What time period are the razors you are referring to? Bainite is a heat treat condition made by cooling the austenized steel to below a certain heat, in a certain amount of time, by going from one heat bath to another of lower temp, producing a condition in the steel that is very tough, yet hard, providing enough carbon is present in the steel. In theory at least, 01 tool steel could be brought to a condition, that in a blade, it could bend 90o, and yet return straight, at the same time having a hardness of around 58 Rc. That would be an incredible feat. I don't know if it has been done, but in theory, it has been stated to be possible. Thanks again. A very interesting post, for me at least.
