淬火温度对大尺寸GCr15SiMn钢球组织及硬度的影响

Effect of Quenching Temperature on Microstructure and Hardness of Large Size GCr15SiMn Steel Ball

利用金相显微镜、洛氏硬度计和XRD衍射仪等仪器,观察了不同淬火温度下直径为85 mm的GCr15SiMn钢球的组织特征和硬度变化规律。结果表明:经825℃淬火、回火后,试样心部组织为板条马氏体+碳化物+块状屈氏体+针状屈氏体,距表面距离大于22.9 mm时,硬度低于58 HRC;经830~840℃淬火、回火后,试样心部组织为板条马氏体+碳化物+针状屈氏体,心部硬度大于59 HRC。淬火温度由825℃升高至840℃时,边部残留奥氏体由11.42%增加至16.06%,心部残留奥氏体由13.49%增加至21.76%。淬火温度在830~835℃范围内,试样硬度、组织和残留奥氏体最稳定。

The microstructure characteristics and hardness changes rule of GCr15SiMn steel balls with the diameter of 85 mm were observed at dfferent quenching temperatures by using metallographic microscope,Rockwell hardness tester,XRD diffractometer,etc..The results showed that the core structure of sample was lath martensite+carbide+massive troostite+acicular troostite after quenching at 825 C and tempering.When the distance from the surface was greater than 22.9 mm,the hardness was lower than 58 HRC.The core structure of sample was lath martensite+carbide+acicular troostite,and the core hardness was greater than 59 HRC after quenching at 830 to 840 ℃ and tempering.When the quenching temperature increased from 825 to 840℃,the residual austenite at the edge increased from 11.42% to 16.06%,and the residual austenite at the center increased from 13.49% to 21.76%.The quenching temperature was within the range of 830 to 835℃,the hardness,microstructure and residual austenite of sample were the most stable.