The Effect of Dilution on Electrochemical Properties of Stainless Steel Clad Layer

Abstract

The effect of dilution on clad-stainless steel layers type (SS309L & SS308) deposited by Gas Metal Arc Welding technique was studied. The dilution effect was investigated by metallographic, and corrosion (both weight and electrochemical) techniques. The metallographic test showed that the first layer SS309 L has pitting corrosion and also some indications of brittle sigma phase at the interface between SS 309L & SS308 layers. The corrosion tests both weight loss and electrochemical tests were conducted in a solution of 4.5% NaCl and their results were in agreement with the metallographic results. In the electrochemical test the passivity region was lesser in SS 309L layer than that in SS 308 layer indicating the better corrosion resistance of SS 308 layer than that of SS309L. All tests results approved that SS 308 layer has superior corrosion resistance than SS 309L despite that the SS 309L is the thicker layer and has more Cr & Ni content but apparently these excellent properties were damaged due to the dilution effect.