Experimental Examination for Decreasing the Oxide Inclusions in Gas Pressure Welding of Rails

Gas pressure welding method is often applicable for joining of rails and reinforcing steel bars. However, if bonding work is inferior, a large quantity of oxide inclusions remain at the weld interface and those inclusions will cause the weld defects. In the previous study, the morphologies of oxide inclusions were estimated by the observation of the transition behavior for inclusions on each welding stage during the gas pressure welding, and the influence of the constituents of base material on the transition behavior was clarified.In this study, we examined the influence of welding conditions on the transition behavior of oxide inclusions to find out the combustion and upset pattern for decreasing the oxide inclusions efficiently.As a result, it was found that the use of oxy/acetylene reduction flame and the low of welding pressure in the initial stage of welding process were effective to decrease the oxide inclusions. Moreover, it was confirmed that the proposal welding condition based on the examination was able to raise the quality of welds than the traditional welding condition.