What is the role of pickling? Why do we use diluted acid for pickling?

Stainless Steel Weld Fittings the role of pickling is to remove oxides on the metal surface. The purpose of using dilute acid during pickling is to corrode the oxides while ensuring that the metal matrix is ​​not overly affected. After all, the dissolution rate of concentrated acid on metal is too fast and difficult to control. The pickling time for stainless steel is generally 5-20 minutes. When the surface of the product completely turns sub-white, it is ready.