What is the normal surface hardness for 316 & 316L stainless 1

[ClareC]

I am using 316 ss in a bushing material in hinges. I am going to surface harden them. first I want to know what is the "normal" surface hardness for this material?

 

[Metalguy]

Annealed 316/L SS should have a hardness of ~ Rb 90.

 

[mcguire]

I have a lot of data on this. 2B finish runs Rb 82 +/- 9 for a six sigma. 2D material is 79 +/- 6. Plate is 83 +/-6.

 

[BobUXL]

The normal surface hardness depends on how it is manufactured. The normal practice for measuring hardness is a mid radius position (Unless is the diameter is < 1/2&quot;, where the hardness is a tensile test conversion). Usually, material below 3/4 to 1&quot; is cold drawn, whereas, sizes greater than 3/4 to 1&quot; is annealed and turned. Now let's talk about surface finishes. Mills are now turning to burnisher/straightening technologies to straighten bars. This eliminates the need to grind surfaces. But these straighteners induce a cold worked outer layer on the material. So is the midradius hardness come in at 212 Hbn, the surface could be at 240/250 Hbn and as high at 270 Hbn, depending on the amout of straightening pressure they use. If the material gets ground, then the surface stresses reduce. This straightening layer can extend .020 to .030 into the surface.