Has anyone else had cracking issues with Stavax.
How did you overcome this ? we need the corrosion
resistant properties and the hardness.

Cheers

We use this steel quite often never had a problem.
Does your part have pockets with sharp corners?
If so that would be a problem area.

Micro Fusion Technology has on occasion been presented 420 Stainless (Stavax) that has cracked. Most frequently the cracks are in the vicinity of water lines. Other occasions large cavity tools that were edm'd start to finish without any stress relief measures during the process. Other times the culprit seemed to be related to heat treat procedures....too soft or too hard and of these usually the latter. Should you like to further discuss your particular situation please contact me....

Lex Harrelson
Micro Fusion Technology
www.micro-fusion.com

Often cracks occur in 420 SS, originating from the stresses produced when tapping waterlines. Therefore, some mold makers utilize threadless waterline plugs counterbored into the end of the circuit, retained by the mold base pocket.

Ed Severson, technical manager at Bohler-Uddeholm, has written an article 'Corrosion cracking of stainless steel', where he states: "In threaded areas, the tensile forces created by plugs can be more than enough to generate stress corrosion cracking, even when the mold id not operating".

Ed can be reached at ed.severson@bucorp.com.

The reason for your cracking problem could be due to several factors. Important mentioning are:
Surface finish of the cooling holes. Rough drilled cooling holes could cause cracks.
Are you double tempering the material after hardening and are you doing the tempering immediately after hardening?

We use Stavax on a daily basis and very rarely do we have any problems with cracks.