Abstract:
A temper bead welding of carbon steel using a shielded metal arc welding (SMAW) process was performed to study microstructure and hardness of the weld metal. A material using in this experiment was ASTM A36 carbon steel plate that was 50 millimeters in width, 150 millimeters in length and 5 millimeters in thickness. The welding electrode was AWS A5.1 E7016. The experiment was divided into 2 parts. Firstly, the effect of welding bead overlap distance on the weld property with the welding current of 90-110 amperes was investigated. Secondly, the effect of the welding layer on the weld property with 6 welding layers and the welding current of 120 amperes was inspected. From the study and analysis on macro and microstructure of the heat affected zone (HAZ), it was found that there was the alteration in microstructure and more rough grains shape than in the fusion area. The microstructure of the tempered area was improved and showed the decreasing of hardness lower than the base metal and HAZ. When compared the hardness of pre- and post- temper, it was revealed that the hardness of the weld metal decreased in all weld layers.