Building up Stainless
Building up Stainless
(OP)
Visited an investment casting foundry last week. The owner said that he 'built-up' 316SS from 304 by adding Mo to the melt. He explained that he could build up various different metals this way. He verified the composition using a spectrometer he has in-house. He would not do this if it were to be a code vessel or require some special certifications or we didn't like it. However he could provide certified MTRs of each heat with his spectrometer as it is NIST traceable.
I've never heard of a small foundry doing this. Is it acceptable? It seems as if it is based on my judgement alone.
I've never heard of a small foundry doing this. Is it acceptable? It seems as if it is based on my judgement alone.





RE: Building up Stainless
The caveats are:
Can they produce a homogeneous material?
Do they have a way to properly sample the material for the physical testing, if required?
Watch for tramp materials.
Carbon control is difficult.
I think that if you just need 316 S/S for corrosion resistance and not pressure containing parts that come under any code you are ok to use.
The bit about traceable is that he uses a NIST standard sample for calibration.
Be careful as I worked on the NIST Sample Program years ago.
RE: Building up Stainless
RE: Building up Stainless