材料期刊网

Improving the strength of 2401 MPa maraging steel weldments is studied in this investigation. Solidified structures of weld metal are controlled by electron-beam scanning welding so that the strength of weld metal can be increased by 10%. This result is equal to that of aging treatment after welding. Simulating the electron beam isothermal heating process, local aging treatment is done on the joint and the best parameters of heat treatment are attained by means of experiment. The ultimate strength of the joint can reach 96% of the base metal's. The ultimate strength of the joint after electron beam isothermal heating local aging treatment is 93% of the base metal's. This agrees with the result of simulation. The strength of the treated joint is equal to that of solution and aging treatment after welding. The fracture appearance shows small reinforced dimples. The amount of residual austenite increases by 30%. Residual austenite uniformly distributes at the boundaries of cellular dendrites. Ti and Mo are found to segregate at the boundaries and form reinforced phases consisting of Ni and Ti or Ni and Mo, respectively. A new opinion that electron-beam high-speed isothermal heating local aging treatment strengthens austenite but not martensite to improve the strength of joints is pointed out, basing on this investigation.