Study On B~+ Steel Castings Welding Technolog

With the rapid development of China's national economy, rail transport plays an increasingly important role in economic development. In order to ensure the capacity and efficiency of railway transport, the Ministry of Railways develops speed and heavy duty vehicles, requesting the higher performance requirements of steel.B+ grade cast is only added chromium and nickel, meeting A.A.R on the provisions of the requirements of the chemical composition and mechanical properties. B+ grade cast is better than the B grade cast comprehensive mechanical properties of steel. And it has low cost, simple process, good smelting and casting. B+ grade cast used in bogie bolsters and side frames, etc.Start with the reaserch of B+ grade cast performance, large amount of tests and vast reaserch were executed on the weld technic test, design of the weld scheme and the validatory test of the joint, which were based on the lucubrate of B+ grade cast weldabilities and the factor affecting the joint performance. gas shielded welding and shielded metal arc welding of different welding processes have different mechanical properties and microstructure at room temperature. It is the best welding technology at room temperature by using Gray correlation to calculate mechanical properties and microstructure analysis. Then studying welding at low-temperature by the best welding process at room temperature。The results show that the carbon equivalent of B+ grade cast amounted to 0.505% and the Crack rate of oblique Y-groove is well over 20%.So the welding of B+ grade cast is poor, it is recommended preheat. And properties of welded joints must be different by using different welding linear energy of gas shielded welding and shielded metal arc welding. The highest overall performance of welded joints are made by Small welding linear energy of shielded metal arc welding and middle welding linear energy of gas shielded welding using gray correlation to calculate.