Study On Microstructure And Properties Of WELDOX960E High Strength Alloy Welded Joints

WELDOX960E high strength alloy is one of new generation’s high strength low alloy, it is especially suitable for the low weight and high requirement bearing structure because of its small grain, high cleanliness, high yield strength and good impact resistance. However, the development time of WELDOX960E high strength alloy is not long, the system research of its weldability is not much. Therefore, in order to further improve the welding quality of Chinese railway crane boom, ensure the safe operation of our country’s railway crane, it is necessary to conduct a comprehensive system of research of welding technology of WELDOX960E.In this paper, the microstructure and properties of welding joint welded with Union X90, Union X96, Phoenix SH Ni2K130are studied through the small iron research crack resistance test, tensile test, bend test, impact test, hardness test, metallographic microstructure and fracture morphology analysis, and it provides theoretical basis for the practical production of the WELDOX960E railway crane boom.The results show that the WELDOX960E welded with Union X90and Union X96, the section crack rate and the surface crack rate was zero; the WELDOX960E welded with Phoenix SH Ni2K130, preheat to75℃, the section crack rate was97%, the surface crack rate was96%; preheat to150℃, the section crack rate and the surface crack rate were zero. The tensile strength of the welding joint welded with three kinds of welding materials is slightly lower than the parent metal, the WELDOX960E welded with Union X90and Union X96are more suitable. The bending performance of the welding joint welded with Union X90, Phoenix SH Ni2K130was good, but the welding joint welded with Union X96cracked. The impact energy values of welding joint welded with three kinds of welding materials are not much difference. Hardness test shows that micro-hardness distribution trend of the welding joint welded with three kinds of welding matericals are similar, the fusion zone hardness value are high and the HAZ have the softening zone.Under the condition of test process, three kinds of the weld microstructure are acicular ferrite and a small amount of granular bainite, which Union X96and Phoenix SH Ni2K130are a small amount of proeutectoid ferrite. The coarse grain zone are M-A island shaped distribution in the ferrite matrix, acicular ferrite, granular bainite and a small amount of lath martensite. The fire area are small granular bainite and blocky ferrite.