drywall screw specifications

If the coating roughness is not caused by the above reasons, it may be caused by impurities in the plating solution. Can take a small amount of electroplating solution, filtration test, and then take a small amount of electroplating solution, with zinc powder treatment after the test, check the problem is solid particles or copper, lead and other foreign metal impurities caused by. One by one, it’s not hard to find the cause of the problem. Galvanized iron wire coating blister, poor adhesion.