Effects of welding on the change of microstructure and mechanical properties of low carbon steel

Abstract

Steel construction is mostly connected by using a welding technique. The result of the welding process can cause the change of mechanical properties of the welding zone. Therefore, it needs to be reviewed to guarantee the quality of the welding zone. This research aims to assess the effect of welding on the change of microstructure and the mechanic characteristic of welded connection. Low carbon steel was welded by using Shield Metal Arc Welding method (SMAW) with electrode E7016, diameter 2,6 mm. Type of notch used was single V with angle 70° and welding position was 1G. Then, the Charpy impact test, Rockwell hardness and micro-macro structure monitoring on the welding zone including base metal, Heat Affected Zone (HAZ) and weld metal, are conducted. The results show that the highest impact toughness value at metal welding area is 251 joule/mm2, and lowest impact toughness is at the heat affected area (HAZ) is 119 joule/mm2. Hardness values of welding zones are found of about 87,6 HRB for weld metal, 73,9 HRB for HAZ zone and 67,1 HRB for the base metal. The microstructure of weld metal zone, HAZ and base metal are included on ferrite and pearlite formed by welding on low carbon steel AISI 1010 observer by using an optic microscope.