高炭素鋼の狭開先自動ガスシールドアーク溶接

抄録

The rail is a typical steel material of the high-carbon steel and the improvement of weldability is an important technological problem. In narrow gap gas shielded arc welding of rail, effects of process parameter, carbon content in weld metal and post heat treatment were examined by observation of defect and microstructure, hardness, tensile tests of welded joints.
By adjusting temperature of the water-cooled copper block surrounding the rail welds, it is possible to control heating to the base metal and thus to improve the weld quality. With post heat treatment and suitable welding condition, properties of welds are improved. Control of carbon content in weld metal is considered to be a factor of hot crack prevention. The MnS type inclusion exerts the influence on the hot cracking in the heat-affected zone and it is possible to prevent hot cracking by applying the suitable process parameters.