等温处理时间对触变挤压锡青铜轴套的组织和性能的影响

Effect of Isothermal Time on Microstructure and Properties of Thixo-extruded Tin Bronze Bushing

采用冷轧-等温处理SIMA法(CRITSIMA法)制备半固态锡青铜坯料并将其挤压成锡青铜轴套,研究了等温处理时间对其微观组织和力学性能的影响。结果表明:随着等温处理时间的延长锡青铜轴套的平均晶粒尺寸随之增大,晶粒的粗化速率为296μm^(3)/s,形状因子先增大后减小,布氏硬度和延伸率先提高后降低,抗拉强度逐渐降低。在910℃等温15 min的锡青铜轴套其综合性能最高,形状因子为0.74,平均晶粒尺寸为63.56μm,抗拉强度为368 MPa,延伸率为4.5%,布氏硬度为126 HBW。

Semi-solid tin bronze blanks was prepared by cold rolling-isothermal treatment SIMA method(CRITSIMA method),and then tin bronze bushing parts were extruded.The effect of isothermal treatment time on the microstructure and mechanical properties of thixotropic tin bronze bushing parts is investigated.The results show that with the increase of isothermal treatment time,the average grain size gradually increased,the coarsening rate of solid grain is 296μm^(3)/s,the shape factor first increased and then decreased,the Brinell hardness first increased and then decreased,the tensile strength gradually decreased,and the elongation first increased and then decreased.The microstructure and comprehensive properties of the tin bronze bushing are the best when kept at 910℃ for 15 min.The shape factor is 0.74,the average grain size is 63.56μm,the tensile strength is 368 MPa,the elongation is 4.5%,and the Brinell hardness is 126 HBW.