Grinding and Polishing Stainless Steel

[OSUengr]

When polishing 304 stainless with a 24 grit belt grinder, what could cause the stainless steel to flake off and produce divets and pits in the material? Any advice will be greatly appreciated.

 

[EdStainless]

Are you doing this wet?
Why are you using such a rough abrasive? I would expect tearing of the metal with 24g.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[OSUengr]

We've used this grit for many years with no problems. We are not doing it wet. Could there be an issue with the metal?

 

[unclesyd]

There are a number of conditions that can cause what you describe to a varying degree.

I would start with a worn out out sanding belt.
This in turn could cause one to apply too much pressure on the belt.
The wrong abrasive on the belt where the grains are moving the metal instead of cutting it.
Not clearing the debris from the cutting area.
Not keeping the area cool.

What shape is the part in question?
Wet or Dry process?
What is the abrasive?

 

[OSUengr]

28ft diameter ring for tank head and rotating at 90sec/rev. We've seen this pitting condition in the past with lesser quality materials. We've polished many heads in the past starting with the 24-36 grit abrasives. The polishing started with very little pressure.

 

[EdStainless]

Two things come to mind.
Look at the belts. The abrasive or the bonding may have been changed. If either is harder than it used to be it might not break down as quickly and cause more tearing.
Make sure that the pressure is light.
Related to the metal, it may have been over oxidized or over pickled in processing. You would get this pull-out until you are below this damaged layer of metal.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube