Noob question about forging heat

[Ed Fowler]

Jim: I only speak about 52100 and partially about 5160.
Theoretically we are safe heating a billet to 1,725f. before grain growth can occur, we cut it off at 1,625 just to be safe.

Naturally the steel we use has been worked down at the Mill or we would be starting with billets way bigger than we can handle. They forge at much higher temperatures.

Our best blades come from our 5 1/2 inch round bars when we keep the temp low while forging.

We have also seriously worked with steel from about 2" round bars of 52100E and 1 inch bars of 5160. The low temp forging has always resulted in better performance blades for us.

The finer the grain you have developed in a blade, the lower the temp. at which it can grow. This is another reason we call for our highest forging temp. at 1,625f.

 

[me2]

Ed
Am I to understand that the best steels are never heated above 1650 after they are poured into a billet?

This is not the case. The deformations produced in a rolling mill are much greater and much more uniform than can be produced on the scale of a hand hammer or even a home power hammer. More than one person, each with a good understanding of dynamic recrystallization, oversees the hot rolling mills.

Ed, so the only thing you would change from Matt's post is the basic idea behind it?

Why do you never quench from the tempering temperature? Isn't it worth at least one try to see what happens? The source I referred to says it prevents undesirable precipitates from forming during the slow cooling from the tempering temperature. Of course I'm sure it's steel specific, and may not work on the steels you use. IIRC, it's most effective when combined with some nickel content in the steel.

 

[Rick Marchand]

Roman Landes is the man who first told me about quenching after the temper. He has hard (pardon the pun) evidence to support his claims.

 

[Ed Fowler]

me2: there are great men of science and industry and there are those who would rather play golf. Obviously Matt has some good ones he knows or works with and this is great. I sincerely hope they get interested and share what their jobs will let them share.

 

[Ed Fowler]

me2: sorry I did not answer the rest of your question. I read about the quench after temper and as I remember it was steel specific and did not apply to 52100 or 5160, sorry I don't remember why, it has been years since I read about it.