Split Dies

[rwj]

I was making custom dies 35 years ago, pre RUM days when we used the 404 Jeffery case then for an improved Lapua case. Never cracked a die. Then I had a few 243 AI dies that cracked. I called Richard BeeBe (SP) at Redding. He told me my heat treater tried to help me out by putting a thick skin on the die. I usually had to wait or pay extra for a thin skin. They were used to treating solid parts.

High hardness (RkC > ~ 62) in steel often results in low ductility (< ~ 8%) and the part being prone to a cracking failure mode.

 

[Webster]

High hardness (RkC > ~ 62) in steel often results in low ductility (< ~ 8%) and the part being prone to a cracking failure m. ode.

I assume the are not carburized? Austenitize at a high temp and quenched typically in a special oil. My first guess is still extreme stress from quenching from a high temp.