Corrosion Behaviour of 316 Austenitic Stainless Steel Cladding on Copper Coated Low Alloy Steel by Gas Metal Arc Welding

Abstract

Cladding has developed growing interest among engineers for providing greater corrosion resistance and erosion resistance of the surface of low grade steel components in aggressive environments. Austenitic stainless steel yields satisfactory results as a clad material and successfully used for last few decades. Among different techniques producing quality clad parts, gas metal arc welding is a popular method for cladding due to its simplicity and cost effectiveness. Corrosion resistance of the clad part depends on different microstructural phases as well as alloying elements present in clad layer. Copper, one of the austenising alloying elements, is used to increase corrosion resistance in steel especially in sulphuric acid atmosphere. In the present investigation, austenitic stainless steel (316) is clad by means of gas metal arc welding (GMAW) on copper coated E250 low alloy steel using 100% CO 2 as shielding gas. Copper coating is done on low alloy steel by electroplating process. Single layer cladding is done keeping 50% overlap. Process parameters of GMAW like welding current and troch travel speed are varied in three levels, keeping welding voltage constant. Heat input varies accordingly. Corrosion tests are carried out in three different media (ferric chloride, copper chloride and sulphuric acid solutions). Experimental results show that copper addition improves corrosion resistance to a great extent in sulphate atmosphere, moderately in ferric chloride and the least in case of copper chloride atmosphere. The corrosion rate decreases at higher heat input on the whole. In every case, the cladding exhibits much better corrosion resistance than the base metal.