Microstructure and precipitated phases of heat treated Q890 high strength steel were studied by using thermodynamic calculations and experimental equipment such as scanning electron microscope and transmission electron microscope.The results indicate that the microstructure of the quenched tested steel is lath martensite,a small amount of bainite,(Nb,Ti)C and Cu-rich nanoscale precipitated phase,the average size of precipitated phase is 42.09 nm,the volume fraction is 0.66％,and the precipitation strengthening component is 89.21 MPa.After low-temperature tempering at 200 ℃,the microstructure of the tested steel shows a little change,the precipitated phases grow slightly,and the precipitation strengthening component decreases.After high-temperature tempering at 600 ℃,the microstructure of the tested steel is tempered sorbite,a small amount of bainite and a large amount of Fe-rich M23 C6 precipitate phases.The precipitated phase particle size significantly increases,with average size of 52.29 nm and volume fraction of 8.55％.The precipitation strengthening component is significantly increased to 271.08 MPa.
关键词
Q890高强钢/热处理/析出相/显微组织
Key words
Q890 high strength steel/heat treatment/precipitates/microstructure
维普
万方数据