OPTIMIZATION OF PROCESS PARAMETERS FOR A SOLID-STATE-WELDED AISI 430 STEEL JOINT WITH THE GRG REINFORCED RESPONSE SURFACE METHODOLOGY

High-temperature applications such as heat exchangers and burner tubes employ AISI 430 steel. A larger heat-affected zone, undesired metallurgical changes and higher hardness in the weld area occur when fusion welding this type of steel. The study investigates the feasibility of welding ferritic stainless steel AISI 430, utilizing a solid-state method (continuous drive friction welding). The experiment uses an L27 orthogonal array and three levels of variation in the welding parameters such as frictional pressure, forging pressure, friction time, forging time and rotational speed. Tensile strength, axial shortening and impact toughness are the observed quality characteristics. In an integrated approach of the grey incidence reinforced response surface methodology, the benefits of the grey relational theory are merged with the statistical analysis of the response surface methodology to determine the ideal friction welding inputs (frictional pressure – 59.95 MPa, friction time – 4 s, upset pressure – 68.5 MPa, forging time – 3 s and rotational speed – 1399 min–1). The AISI 430 steel joint’s qualities are improved by 2.25, 12.74 and 7.89 % in terms of the maximum ultimate tensile strength, axial shortening and impact toughness, respectively.