EXPERIMENTAL STUDY ON MECHANICAL PROPERTIES AND MICROSTRUCTURE OF 2.25CR1MO0.25V STEEL BY THE INFLUENCE OF HEAT TREATMENT AND WELDING

摘要

In this paper, the mechanical properties and microstructural changes of 2.25Cr1Mo0.25V steel under different heat treatment and welding process were investigated. The heat treatment of steel during practical processing is taken as a reference. Different heat treatment time are used to obtain samples with different condition. Automatic submerged arc welding was used to obtain welding sample. The mechanical properties of different samples are obtained by tensile test; the evolution of microstructure and precipitates of different sample with heat treatment and welding was studied on scanning electron microscopy. The experimental results show that with the increase of heat treatment time, the strength of the samples decreases and the plasticity remains nearly constant. Heat treatment also affects the precipitation of carbides; the longer the heat treatment time is, the more precipitates are. Compared with the base metal, the welding metal sample has higher strength. The amount of precipitates in welding metal is much larger than it in base metal. The research on precipitation shows that there are different kinds of precipitates which have different morphologies in welding metal.