2015 Volume 56 Issue 12 Pages 2063-2069
The effect of the quenching rates on microstructure and impact ductile of X12CrMoWVNbN10-1-1 steel was investigated. The samples were heated to 1080°C for 16 h and quenched with different rates to room temperature, then tempered at 700°C for 24 h. It was found that the critical quenching rate of suppressing the precipitation of Cr-rich M2N and Fe-rich M3C was faster than 1.5°C/min and 10°C/s, respectively. And the critical quenching rate for the precipitation of ferrite was in the range of 1∼1.5°C/min. The impact energy began to decrease when the tempered sample was quenched with a rate of 1.5°C/min due mainly to the precipitation of Cr-rich M2N based on the careful conducted analysis of the microstructure and fractography.