The use of 17-4PH Stainless Steel in Ball Valves

[rvivac]

Hello all!

I have a series of specs which asks for the use of the 17-4 H1150 Precipitation Hardening Stainless Steels in the stem and trunnion of ball valves.

Until now, what I know is that this is a very good material for corrosion and high yield and tensile stress.

The use is in the entry lines of a FPSO, which comes with all sorts of sulfur content.

Why not to use other common materials such an austenitic SS?

Thanks!

 

[valvit]

You've answered the question for yourself. 17-4 has higher SMYS and UTS than anything in the austenitic family, so parts of the same size will be stronger and will have higher allowable stress values. If you have high sulfur content, you need to be concerned with H2S content. 17-4 is highly restricted according to NACE rules.

Valvit