Home Made Tooling??

[ENT]

Ha ha, it depends on the engine. Most of the US passenger car intake valves are low to moderate alloy content martensitic steels hardenable at 1550F for 15 minutes followed by oil quench (air cooling won't harden fully and plain water will likely crack the part, but if you have access to PAG quenchant at the proper concentration, that will work). Tempering temperature will depend on what final hardness you want, but generally 1 hour at 300F -500F will temper without much loss of hardness.

If you are going to harden this using a torch, you want to get to a medium reddish-orange color with just a hint of speckling (oxide forming and popping off the surface look like black speckling flecks)

Edited October 2, 2008 by ENT