淬火工艺参数对40Cr合金钢组织性能的影响

采用光学显微镜(OM)、电子万能拉伸试验机、冲击试验机等设备和手段,研究了淬火工艺参数对40Cr合金钢调质组织和性能的影响。结果表明,当40Cr合金钢奥氏体化完全、晶粒未粗化的情况下,PAG淬火液浓度是影响其组织和性能的主要因素,PAG淬火液浓度从2.60%升高至3.20%,钢的强度降低,塑性增加;PAG淬火液浓度继续升高至4.00%时,40Cr合金钢中铁素体含量增加,同时下贝氏体含量也增加,其强度增加,塑性降低。当40Cr合金钢淬火温度为870℃、淬火频率为21Hz、PAG淬火液的浓度低于3.20%时,钢中可避免出现铁素体和下贝氏体组织,调质处理时可获得理想的回火索氏体组织。

Effects of quenching process parameter on microstructures and properties of 40Cr alloy steel

The microstructure and properties of 40Cr steel treated by different quenching process parameters were studied by means of optical microscope (OM),electro- mechanical universal testing machine and shock testing machine.The results show that when the austenitizing of 40Cr steel was completed and the grain was not coarse- grained,the concentration of PAG quenching liquid is the main factor to influence its microstructure and mechanical properties.With concentration of PAG quenching liquid rising from 2.60% to 3.20%,the steel strength decreasing and the plasticity rising.Then continued to increase the concentration of PAG quenching liquid to 4.00%,the content both ferrite and lower bainite increased in the 40Cr steel.However,the strength increased a little and the plasticity decreased.When the quenching temperature is 870 ℃,the quenching frequency is 21 Hz and the concentration of PAG quenching solution is less than 3.20%,the ferrite and lower bainite can be avoided and the ideal tempered sorbite can be obtained in 40Cr steel after quenched and tempered.