Fracture toughness of 12Cr2Mo1R steel at elevated temperature

The microstructure,tensile properties,and fracture toughness of 12Cr2Mo1R steel were studied. The results indicate that this steel is characterized by a bainite microstructure,in which several types of carbides precipitate along the ferrite laths. As the temperature increases from room temperature to 375 ℃,the strength of the steel increases slightly and the fracture toughness clearly decreases. However,when the temperature continues to increase up to 500 ℃,the strength decreases and the fracture toughness increases. At all the temperatures investigated,the strength and toughness of the developed 12Cr2Mo1R steel were capable of meeting the design requirements of a high-temperature gas-cooled reactor. The fracture of 12Cr2Mo1R steel at high temperature typically occurs in the ductile mode.