The Effect of Welding Pre Heating of SMAW and GTAW on Mechanical Properties of SA .106 Gr. B Pipe of Energi Sengkang Co.Ltd

Abstract

This research aimed to analyze the differences in mechanical properties, such as tensile strength and hardness of the materials of SA.106 Gr B. experiencing SMAW and GTAW welding with preheat treatment. The research activities were conducted in the Laboratory of Materials Science of the Department of Mechanical Engineering, Faculty of Engineering, Indonesia Christian University of Paulus, Makassar. The material Preheating was done in the workshop of PT. Energi Sengkang. The method used was to create a specimen of the SA.106 Gr.B material experiencing the SMAW and GTAW welding with the preheat condition of 0°C, 110°C and 125°C. In order to determine the strength of the material, the mechanical test, i.e. the tensile test (ASTM E 8M), Hardness test (Brinneil), and microstructure observation were done. The research results indicated that preheat process had an influence on the mechanical properties of the material before welding. In the process of SMAW and GTAW welding, the increase of preheat temperature had an impact on the increase of the value of the tensile test of preheat temperature of 125°C. In the GTAW welding, it was found that σu = 54.51 kgf/mm, while in SMAW welding, it was found that σu = 53.26 kgf/mm 2 . In hardness test, it was found that the increase of the preheat temperature had an effect on the hardness in the welding area was 43.22 HB while in the GTAW welding it was 43.32 HB.