摘要
本文研究了回火温度对弹簧钢65Si2MnWA 组织和性能的影响,重点探讨了疲劳断裂性能及其疲劳与断裂机理。试验结果表明,随回火温度的升高(420～500℃),回火屈氏体变得粗大,碳化物尺寸和间距加大,铁素体回复程度加深。强度升高,随回火温度升高和应力比增大,疲劳裂纹扩展速率增大,门槛值降低,断裂韧性上升。其中,碳化物尺寸和间距是对断裂起关键作用的微观结构参数。从疲劳断裂角度看,弹簧钢65Si_2MnWA 采用860℃油淬,460℃回火较为适宜,因而评价了现行热处理工艺。
In this paper,the temper temperature effecting on the microstructure and property of 65Si2MnWA sping steel have been tested,in particular,on the fatigue property and fracture toughness.Neverthless,fatigue and fracture mechanism of 65Si2MnWA sping steel have been investigated.It is shown that as the temper temperature increases,the as tempered microstructure coarses,the size and distance of carbides increases,δ_5,dσ/dn and Klc val- ues increases,the strength and ΔK_(th) values decreases.The size and distance of Carbides is the key parameter of fracture.Considering on the fatigue and fracture property,quenched in oil at 860℃ and tempered at 460℃ is suitable for 65Si2MnWA sping steel.
关键词
疲劳
断裂
回火
弹簧钢
65Si2MnWA sping steel
fatigue
fracture
temper
microstructure parameter
