Dougher 17-4 PH S.S is susceptible for hydrogen embrittlement. You may find some information / research data in the following papers: 1. Technical reference on hydrogen compatibility of materials by Sandia National Laboratory CA - Edited by C San Marchi / B.P Somer day. see under www.ca.sandia.gov/materials.tech.ref 2. Mechanical behaviour of 17-4 PH S.S in S.C.C and embrittlement in environment hydrogen www.cnpiesb.com Hope this helps C.V.Srinivasan Nishi Engineers Pvt Ltd India June 20, 2009 E-mail: nishi@vsnl.com >I've done some searching through the archives and have not >found any information regarding the compatibility of 17-4 PH >with Hydrogen Gas specifically related to embrittlement of >this type of Stainless Steel. > >My application is %7E6500 PSI dry Hydrogen Gas (100% pure), >and I am looking for a pressure sensor. My experience is >that 304-SS is unacceptable, and 316-SS is acceptable for >the materials in contact with Hydrogen. Many pressure >sensor manufacturers also use 17-4 PH Stainless Steel. > >I recall that 17-4 PH Stainless is typically treated H900 or >H1100 (I think these are the annealing temperatures?), and >that one of these is less suceptable to hydrogen >embrittlement. I would like to find data which supports the >use of either specific grade for gaseous Hydrogen. > >Can anyboy direct me to such data? > >Thanks, >Doug

Dough Please see the posting done by me on June 19,2009 for your earlier query. 17-4 PH grade material and specific research on susceptibility for hydrogen gas service at high pressures - research work done internationally is not very high but only specific projects had done the same to my knowledge. Whether such specific data is fully published or still further research work is continuing is not known at this moment. You will find some useful data on 17-4 PH susceptibility to hydrogen gas service at high pressures from the research work done given in earlier reply by me. Hope this helps C.V.Srinivasan Nishi Engineers Pvt Ltd India August 20,2009 E-mail: nishi@vsnl.com >I've done some searching through the archives and have not >found any information regarding the compatibility of 17-4 PH >with Hydrogen Gas specifically related to embrittlement of >this type of Stainless Steel. > >My application is %7E6500 PSI dry Hydrogen Gas (100% pure), >and I am looking for a pressure sensor. My experience is >that 304-SS is unacceptable, and 316-SS is acceptable for >the materials in contact with Hydrogen. Many pressure >sensor manufacturers also use 17-4 PH Stainless Steel. > >I recall that 17-4 PH Stainless is typically treated H900 or >H1100 (I think these are the annealing temperatures?), and >that one of these is less suceptable to hydrogen >embrittlement. I would like to find data which supports the >use of either specific grade for gaseous Hydrogen. > >Can anyboy direct me to such data? > >Thanks, >Doug