Reciprocating compressor materials selection

[kissjxp]

I have a question on the cylinders materials selection for a reciprocating compressor. It has 90 mol% Hydrogen.

Design pressure: 4600KPa
Design temperature: 90C; MDMT: -7 deg C.

The client choose nodular iron. Is it OK? I am worried about the temperature. Nomarlly, what is the lowest temperature we can use for the nodular iron?

Thanks.

 

[dcasto]

Nodular is also called ductile iron ASTM A395 Grade 60-40-18 is the call out for typical cylinders.

 

[JimCasey]

Hydrogen does not corrode iron and everything I have read indicates embrittlement effects occur in hardened steels or stainless, and at "high temperatures" which are mentioned but not specified. In either case, nodular iron is neither hardened nor at high temperatures. Punch "Hydrogen embrittlement" into Google for reassurance.