Effect of Heat Treatments on the Mechanical Properties of Welded Joints of Alloy Steel by Arc Welding

Hamid M. Mahan

doi:10.24237/djes.2019.12204

Authors

Hamid M. Mahan
hamid19812052016@gmail.com
Baquba Technical Institute, Middle Technical University (MTU), Iraq

Keywords:

Heat treatments, Mechanical properties, microstructure, welded joints

Abstract

This research deals with influence of the heat treatment on welded joints using the shielded metal arc welding (SMAW) on three types of steel with different carbon ratios under constant conditions such as the thickness of metal 20 mm, welding current 120A , voltage 80V, Diameter 15 mm and angle 60 degree. Mechanical tests were carried out to include tensile, bending, micro hardness and microstructure testing. The results showed that the steel with a low carbon content has the highest value of hardness after performing heat treatment in the area of welding line 370 HV. Unlike the moderate carbon- steel, the value of hardness was higher in the 310HV, the tensile strength of steel decreased to 554Mpa when carrying out the heat treatment compared with steel containing higher carbon ratios 523MPa . In the other side improving toughness and impact strength for welded joints on which heat treatments have been conducted after the welding process , where highest impact value was obtained in the high carbon steel 214 J

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