316SS stub-in to CS pipe @ 400degC
316SS stub-in to CS pipe @ 400degC
(OP)
Has anyone used a "hydratect" fitting before? It is a level switch used for steam service. The physical connection relies on stubbing the fitting into the steam header. The problem is that the only option offered by our vendor is 316SS and our header material is CS. We used a 309L electrode.
Our finite element analysis of the junction shows yield stresses at the weld boundary due to differential thermal expansion.
The hydratect fitting is a proprietary item, and the Vendor says "no problem". I have consulted experienced steam engineers also and they say "no problem". Yet I look at the FEA and I see a potential problem. We are currently working on a solution.
My question is for those with steam experience - what is your experince with welding SS in to CS? In particular do you see local yielding as an issue given that it will only happen once?
Our finite element analysis of the junction shows yield stresses at the weld boundary due to differential thermal expansion.
The hydratect fitting is a proprietary item, and the Vendor says "no problem". I have consulted experienced steam engineers also and they say "no problem". Yet I look at the FEA and I see a potential problem. We are currently working on a solution.
My question is for those with steam experience - what is your experince with welding SS in to CS? In particular do you see local yielding as an issue given that it will only happen once?





RE: 316SS stub-in to CS pipe @ 400degC
I may not reply to your specific question. However, the use of Inconel electrode should be a good choice for high temperature service.
What SMAW rod for 316SS to A36 structural?
Thread725-92847
RE: 316SS stub-in to CS pipe @ 400degC
RE: 316SS stub-in to CS pipe @ 400degC
Carbon to Stainless welds are commonly used as high as 700F, typically without problems. At the higher temperatures, inconel weld metal is used to blend the coefficients of thermal expansion. Inconel as a coeffficient of thermal expansion between carbon steel and stainless steel.