掘进机滚刀刀箱用Q355B钢热处理工艺研究

Research on Heat Treatment Process of Q355B Steel for HobCutter Box of Tunneling Machine

通过拉伸试验、硬度测试、冲击试验、压缩试验及显微组织观察,研究了不同正火和淬火工艺对Q355B钢力学性能的影响。结果表明,Q355B钢经900℃正火处理后,其显微组织为铁素体和珠光体,带状组织完全消除,屈服强度、硬度和塑性均有一定程度增加,冲击韧性大幅度提升;Q355B钢经900℃淬火+200℃回火处理后,其拉伸屈服强度和压缩屈服强度分别为743.5、756.7 MPa。不同热处理状态下Q355B钢均表现出优异的塑性,其拉伸断口和冲击断口均为微孔聚集性断裂,部分出现准解理特征。Q355B钢经900℃淬火+200℃回火处理后,满足掘进机滚刀刀箱材料使用性能要求,使用过程中未出现刀箱变形问题。

The effects of different normalizing and quenching processes on the mechanical properties of Q355B steel are studied by tensile test,hardness test,impact test,compression test and microstructure observation.The results show that the microstructure of Q355B steel after normalizing at 900℃is ferrite and pearlite,and the band structure is eliminated completely.The yield strength,hardness and plasticity are all increased to a centain extent,and the impact toughness is significant increased.After quenching at 900℃and tempering at 200℃,the tensile yield strength and compressive yield strength of Q355B steel reach 743.5 and 756.7 MPa,respectively.Q355B steel exhibits excellent plasticity after different heat treatment,and the tensile fracture and impact fracture are characterized by micro pore aggregation fracture,with some of them exhibiting quasi-cleavage characteristics.Q355B steel meets the hob cutter box material performance requirements of tunneling machine after quenching at 900℃and tempering at 200℃,and there is no deformation of cutter box during service.