高品质60Si2MnA弹簧钢的热处理工艺优化

Heat treatment optimization of high-quality 60Si2MnA spring steel

进行了60Si2MnA弹簧钢的奥氏体粗化温度和热处理正交试验,模拟了余热淬火工艺,并确定了最佳热处理工艺。试验结果表明,采用950℃保温20min,随后冷至880℃出炉进行油淬,在400℃回火90min,其综合力学性能最佳,Rm=1810MPa,Rp0·2=1640MPa,A=6·9%,Z=29·1%,AK=19·2J,硬度54·3HRC,均显著超过高品质60Si2MnA弹簧钢的性能指标。将试验得出的余热淬火热处理优化工艺应用于铁道部I型60Si2MnA钢弹条的卷制余热淬火,其各项性能指标均能满足目前高速铁路用弹簧的技术要求。

The austenite coarsening temperature and orthogonal experiment of heat treatment of 60Si2MnA spring steel were investigated. The quenching process by use of residual heat was simulated and the optimal heat treatment process was determined. The results show that the optimal comprehensive mechanical properties of 60Si2MnA spring steel can be obtained by austenized at 950 ℃ for 20 minutes, quenched from 880 ℃ by oil, and then tempered at 400 ℃ for 90 minutes. The tensile strength is enhanced to 1810 MPa, the yield strength to 1640 MPa, the elongation to 6.9% , the reduction ratio of area to 29. 1% , the toughness to 19. 2 J, which remarkably exceed the performance requirements of high-quality 60Si2MnA spring steel. When the optimal heat treatment process of residual heat quenching was applied in I type 60Si2MnA coiled spring for railway, its performance index can meet the demands of spring for high speed railway.