Wet Grinding 52100 shims

[JohnMagna]

we have too many shims in a thicker size and want to grind these down to the thinner size, all other dimensions are the same except thickness. Going to be wet Ground as the 52100 material is already HRC 58 Min.
I am thinking that at a minimum a percentage of the shims need to be etched for grinding burns, and a sampling for Hardness (surface). What about a Temper at say 300F??
Thanks

 

Wet grinding done slowly (feed speeds and depth of grind) should not adversely affect the hardness.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[bobjustbob]

No temper should be required. If ground without burn the parts are fine. If burned, temper is not going to do much to help.

Bob

 

[Tmoose]

How thick are the shims?
How much material is to be removed ?
How flat do they need to be when done ?
Do both sides need to be HRC 58? ( If only because they might be installed "either way" )

 

[JohnMagna]

Thanks guy's for the posts. No temper going to wet grind done slowly with minimal removal per pass.
Will have a sampling etched to verify No Burning.

 

[MagBen]

I have seen often an increase of 1-3 points (HRB) even after a polish wet grinding (240 grits) on a strip product. Grinding creates more or less cold work that increases surface hardness, especially for annealed, relatively soft metals. When your material is already at 58HRC, the increase is probably limited, but does not burden much taking a quick check.

 

MagBen,
Progressive grinding, as done for metallography, would avoid that effect. Not too feasible with standard machine shop tools though.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."