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EMBRITTLEMENT RELIEF OF STAINLESS STEELS
DO STAINLESS STEELS NEED A HYDROGEN EMBRITTLEMENT RELIEF BAKE AFTER PLATING SUCH AS: CHROME, ELECTROLESS NICKEL, SULFAMATE NICKEL, ETC.?
ARE STAINLESS STEELS SUCH AS :416SS AND 304SS ALWAYS A PARTICULAR HARDNESS OR ARE THEY HEAT TREATED TO DIFFERENT HARDNESSES JUST LIKE REGULAR STEEL?
PLATING CONSULTANT - DAYTON, Ohio
2004
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At the risk of having Ted tell me I am having a bad hair day, I have a question. How can you be a plating consultant when you do not know one of the basic principles of plating? This is covered in most of the recommended reading books at this site and is a given in nearly every specification on the particular plate as well as nearly all of the major OEM's. I don't argue with your feelings on this issue, James. But I do know, from participating in dozens of different forums, going back to Compuserve days and continuing through newsgroups like scichem.coatings, that questioning of qualifications usually quickly degenerates into ad hominem attacks and name calling. To discourage that, one of our 'editorial standards' has long been "Everyone is welcome to express their own opinion, and to disagree with others--but not to question their qualifications or to post an ad hominem response" :-) OK, I will play by the rules. In retrospect, I guess a person is his own judge of self appointed titles and qualifications. |
So to answer the question, stainless steels that are hardened (the heat treated martensitics, the precipitation hardening grades, and the cold worked austenitics) DO need the embrittlement relief; sometimes. It depends on your grade, and how hard you've made it, and whether or not the particular specification calls for it. We've got some applications where we would bake after chromium plating but not after electroless nickel, for example.
Get a copy of the old, obsolete, FREE, Mil-H-6875 from ASSIST, the US Government site for their military specifications. Alloys in Tables 1B and 1D are heat treatable stainless grades, and may need baking. Alloys in Table 1C are austenitics, and won't need baking unless they are heavily cold worked.
Another excellent reference, also FREE, is Publication 9014 of the Nickel Development Institute, which you'll find on their site. It's title is "Design Guidelines for the Selection and Use of Stainless Steel" and it's a keeper.
Good luck!
Lee Gearhart
metallurgist - E. Aurora, New York
2004
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