52100 Grain Size

Joined
Jul 3, 2002
Messages
645
I'm playing with my first 52100 and found an interesting thing - to me anyway - and I don't understand it.

I bought ~1/8"bar stock that was hot pounded from rod with a power hammer. I cut some pieces off and heated them different ways and busted them off for tests. (Here's the question, finally.)

The grain size just below the surface is very, very smooth. However the core is coarse. How come ???

All of them were quenched in Goddard's Goup. One piece was heated once and snapped. Then a single temper at 425 and snapped again.

Another triple normalized, annealed, single hardening and snapped. Then tempered and snapped again.

A third piece was triple nomalized, annealed, triple hardened, double tempered, it too snapped (?), and had even smoother grain, but the core was course.

Why is that? Could it be because of the limited forging?

Steve
 
Evaluate your normalizing techniques. Your either going to high in temp. or your not holding it at temp long enough.
 
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