EFFECT OF MIG WELDING PROCESS PARAMETERS ON EROSION AND CORROSION BEHAVIOR OF ASTM A106 GRADE-B PIPE WELDMENTS

Abstract

Evaluating the integrity of the welded pipes used for fluid transportation in processing industries demands certain investigations on the erosion and corrosion behavior under various environmental conditions. ASTM A106 Grade-B pipes are butt welded using an automated MIG welding setup to obtain the optimum output response such as Reinforcement Form Factor (W1), Penetration Shape Factor (W2), and Tensile Strength (W3) in the weldments. The slurry erosion test is conducted on the weldment surface by varying the velocity and erodent concentration in acidic (0.1M H2SO[Formula: see text] and alkaline (3.5%[Formula: see text]wt. NaCl) conditions. Correspondingly, the samples are subjected to electrochemical corrosion test in 0.1[Formula: see text]M H2SO4 and 3.5% wt. NaCl solutions. The SEM investigations carried out on the eroded weldment surface show glimpses of erosion mechanisms such as shallow and deep ploughing, oxide cracks, ridges and valleys, scale formation at some areas attributing to sulphide deposition. The corrosion that occurred on the weldment surface tested under acidic conditions is relatively high compared to the alkaline conditions. The reinforcement form factor is the most preferable weld bead characteristic to obtain better erosion and corrosion resistant weldments in the investigated pipe material.