Effect of Welding Processes on the Mechanical Properties of Hardox 400 Steel Welded Joints

Abstract

The present paper investigates the effect of gas metal arc welding process and shielded metal arc welding process on the tensile, impact, and metallurgical properties of 20 mm quenched and tempered steel welded joints. To accomplish the established aim, double V groove joints with 60° groove angle were welded using gas metal arc welding process and shielded metal arc welding process using low hydrogen ferritic steel consumables. Microhardness studies carried out along and across the welded joints accompanied by the microstructural investigations revealed significant variation within the fusion and the heat affected zone of the weldments. Tensile and impact property studies of the shielded metal arc welding process welded joint shown better properties as compared to the gas metal arc welding process owing to the presence of fine acicular ferrite in the fusion zone due to low heat input. Extensive tempering due to weld thermal cycles has shown a more detrimental effect on the hardness of heat affected zone of all the welded joints with the reduction in hardness to around 50–60% for approximately 70 mm width around welded region.