Narrow gap automatic gas shielded arc welding of high carbon steel

Abstract

Summary Rail steel is a typical high carbon material and has previously been extensively researched to improve its weldability. This paper describes an investigation of narrow gap automatic gas shielded arc welding of rails to determine the effects of the process parameters, weld metal carbon content, and post weld heat treatment through observations of defects and microstructures, hardness measurements, and tensile tests of welded joints. Through adjustment of the temperature of the water-cooled copper block surrounding the rail welds, the heat input to the base material can be controlled and the weld quality thus improved. Suitable post weld heat treatment and welding conditions improve the weld properties. Control of the weld metal carbon content is an important factor in prevention of hot cracking. Hot cracking in the HAZ is influenced by MnS inclusions and can be prevented through application of suitable process parameters.