Topic: Electropolishing pits

What is the main cause of pitting from E/Ping 316L grade stainless? We see it more prevelant on our hose fittings when the surface of the part is from the end surface of the bar stock. We call it "end grain pitting". All of our fitting are made from either solid bar or tubing. Is it possable to optimize the process and or bath parameters to minamize this pitting effect?


Re: Electropolishing pits

It sounds like your metal stock is not homogeneous.  Pitting can sometimes occur when some metals are removed before others and is especially prevalent it situations like what you are describing, at the end of a piece of stock.  It could also be due to a weakening of your chemistry or the age of the chemistry, but if you only notice it on the end stock, I suspect the stock itself is the culprit.  Send off several pieces of stock to a metallurgist and see iof they can identify any disparity in the alloy.

-Dustin Gebhardt, CEF

Advanced Manufacturing/Finishing Engineer


Sanford, NC