Analysis of Mechanical and Metallurgical Properties of Friction Welded ASTM A106Gr.B Carbon Steel Pipe Joints by Varying Upset Pressures

Friction welding is one of the most common methods employed in the joining of carbon and alloy steel tubular sections. In the present work, the analysis of the effect of upset pressure on mechanical and metallurgical properties of friction welded ASTM A 106 Gr. B low carbon steel pipes has been investigated. The test joints were made using continuous drive welding machine with upset pressures of 5 MPa to 8 MPa and evaluated for microstructure, hardness, tensile strength and impact toughness. The weld joints exhibited mostly ferrite and pearlite microstructure in both fully plastically deformed zone (FPDZ), partially deformed zone (PDZ) on the either side of the weld interface and a distinct dynamically recrystallized ferrite pearlite microstructure was observed in the FPDZ at the weld centre line. Better tensile properties were observed in case of the joints made with upset pressure of 6.4 MPa. It is observed that the weld region is stronger than base metal and the hardness has increased with the increase in the upset pressure. Marginal reduction in the toughness was noted with the increase in the upset pressure.