The "R" designation in 316R
The "R" designation in 316R
(OP)
I am trying to figure out what the "R" designation is for a fastener stating it's 316R. I would appreciate any help to shed some light on this? I've looked on the web and several books and cannot find the exact "R" processing and chemistry requirements.
Thanks in advance for your help!
Wilson Silverthorne
Thanks in advance for your help!
Wilson Silverthorne





RE: The "R" designation in 316R
Is there any other reference to the material other than "316R"?
RE: The "R" designation in 316R
The entire material designation is:
SS-316-R Austenitic Stainless Steel per MPIF STD NO.35.
I do not have access to MPIF STD 35 but it is supposed to be equivalent to ASTM B883 which does not list 316R? I have a call into the supplier of this fastener and they have not been able to give a good answer either. I'm starting to wonder if it's a typo. But, I found a research paper on the internet that references a 316R as a standard grade of 316. What a mystery.. ha ha :)
Thanks again for the help.
Wilson
RE: The "R" designation in 316R
RE: The "R" designation in 316R
Lists the grade but simply says that it is equivalent to 316.
RE: The "R" designation in 316R
thanks for the leads. I found the food grade reference too? I also found a Precision Metals Service that has an internal spec PMS 316R. I'm now trying to find out where my supplier got their raw material. The excitement never ends? Thanks again for your input!
Wilson
RE: The "R" designation in 316R
RE: The "R" designation in 316R
Maui
RE: The "R" designation in 316R
I'm still awaiting the supplier to call with hopefully an answer. Glad to see I wasn't the only one confused. Thanks for checking the MPIF #35, since I didn't have access to that spec you've answered an important question. It's seeming like, as was suggested by TVP, this may be a company designated "R". Thanks again for all your input. This is my first post to this site, and I'm very impressed!
Thanks
Wilson
RE: The "R" designation in 316R
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: The "R" designation in 316R
RE: The "R" designation in 316R
RE: The "R" designation in 316R
Best Regards
Wilson Silverthorne
RE: The "R" designation in 316R
Years ago I mean at least 35 years ago - I once worked for a nut and bolt company that made hardware from powder. I think the material was a brass or bronze nut/bolt. I was surprised too when I got there. I loved that job so much I quit after two weeks.
wlovison@toyopumps.com
RE: The "R" designation in 316R
The "R" designation in SS-316-R is a 15 year old designation from the MPIF standard 35. The R refers to the sintered material density, in this case 6.4-6.8g/cc. Most powder metal parts have some porosity which reduces the metals density from the theoretical density of wrought material (in the case of 316 the theoretical is approx 7.9g/cc).
There is no current equivalent standard to the old R standard but the closest match for a fastener application is probably SS-316N2-33.
Hope this helps