S136 Assab steel sand spot issue 1

[sizzer33]

Hi all,

We've been experiencing some issues on S136 steel for the past few projects. We have had sand spots(sand like pot holes) on polished surface of S136 steel. The steel were hardened to HRC50. WE're in China and the steel are purchased from dealer in China with cert and everything. So with the Authenticity of steel aside, is there any other cause for this problem?

 

[richardbuss]

Hello Sizzer, only way to know for sure would be to get a sample checked. If the material really is from Uddeholm which is by no means guaranteed even with a TC in China, then you shouldnt have a problem. I am in China everymonth and would be happy to have a look.

http://www.doerrenberg.com.sg

 

[sizzer33]

the material is from Assab,its called Stavax ESR S136 steel.

By the way, we re-EDM and repolish the surface about 0.02mm altogether and the spots are gone. Apparently its an over-polish issue and not pitting corrosion as we first thought. We're also going to coat this surface to avoid further corrosion issue which we heard are quite common on these stainless steel.