Effect of Welding Joints on the Mechanical Properties and Microstructure of Wear Plate Materials

Abstract

Welding is one of the commonly used metal joining techniques in industry. This research focuses on welding using the Shielded Metal Arc Welding (SMAW) method to connect two metal parts using heat sources and additives. The purpose of this study was to evaluate the tensile strength, hardness, and microstructure of the Hardox 400 test material. Hardox 400 test material was obtained from PT. Vale Indonesia and tests were carried out at BLKI Makassar for tensile testing, as well as at the Engineering Materials Laboratory of the Muslim University of Indonesia for hardness and microstructure testing. The tensile test results showed that Hardox 400 material that had been welded with the SMAW method had a maximum tensile stress of 591.266 MPa and a strain of 6.567%. In comparison, unwelded (standard) specimens have a maximum tensile stress of 777.512 MPa and a strain of 6.980%. In terms of hardness, the highest average hardness values occurred in the right base metal area of 68 N/mm², the right HAZ of 61 N/mm², the weld metal area of 55.33 N/mm², the left HAZ of 61 N/mm², and the left base metal of 68 N/mm². Unwelded (standard) specimens have a hardness value of 66.8 N/mm². Microstructure analysis showed that in the weld metal area, there is an austenitic phase, while the HAZ area consists of Martensite and Bainite phases. The Martensite phase dominates the base metal region.