Repro frame alloy?

[Chuck Heald]

Edgar,
When the casehardening process of heating and quenching is done, 8620 will core harden. I can't recall the reference I found on this at the moment. The core came up to about twice the strength of normalized.

[edgarspencer]

Any carbon steel will have a higher hardness (Brinell), and, logically, UTS will be higher, when quenched and tempered than when Normalized and tempered, however ductility will suffer dramatically. Quenching will give you a higher surface, or near surface hardness, but the core will be less so. Air quenching after normalizing will give a more uniform cross sectional hardness.