Study on Fracture Properties of P91 Steel Mis-matching Welded Joints

The influence of the strength mis-matching on the fracture properties of the different regions in P91 steel weldments was studied by the JR resistance curve method.And the hardness distribution along strength mis-matching P91 steel weldments was analyzed.The results show that the welding thermal-cycle on its mechanical property of the HAZ has no evidence effect.The fracture resistance of the welded joints of the low-matched P91 steel weldment is higher than that of high-matched weldment,that is,the lower strength matching-ratio(the weld metal strength to the base metal strength) is favorable to improve the fracture properties of the weld metal.For the fusion line,the experimental results are the similar rule to that of the weld metal,namely,the fracture resistance of fusion line increases with the decreasing of the strength matching ratio.In general,the fracture properties of the weld metal are superior to that of the fusion line for all kinds of P91 welded joints with different strength matching ratio.