Q-I-Q-T热处理新工艺下两种奥氏体化温度对60Si2CrVAT弹簧钢疲劳强度的影响  

Effect of Austenitizing Temperature on a Spring Steel 60Si2CrVAT Fatigue Strength with the Q-I-Q-T New Heat Treatment

作　　者：高卫星[1] 梁益龙[1,2] 

机构地区：[1]贵州大学材料与冶金学院,贵阳550003 [2]贵州省材料结构与强度重点实验室,贵阳550003

出　　处：《材料导报》2013年第8期81-84,共4页Materials Reports

基　　金：国家科技支撑计划(2007BAE11B03);贵阳市重大专项((2009)筑科1合同字第1-4-3号)

摘　　要：研究了淬火-等温-再淬火-回火(Q-I-Q-T)热处理新工艺下两种不同奥氏体化温度对60Si2CrVAT弹簧钢疲劳强度的影响,得到新工艺显微组织为马氏体/贝氏体及少量薄膜状残余奥氏体的复相组织。结果表明:低温奥氏体化状态较高温状态,马氏体、残余奥氏体的量减少,贝氏体的量增加。由于高温奥氏体化状态晶粒粗化,晶界处淬火应力集中,疲劳裂纹主要在晶界界隅处萌生;低温奥氏体化状态晶粒细化,疲劳裂纹主要由内部夹杂物引起。低温奥氏体化状态疲劳强度高于高温奥氏体化状态。Effect of two austenitizing temperature on fatigue strength of a spring steel 60Si2CrVAT in the quenching-isothermal-quenching-temper（Q-I-Q-T） heat treatment process was studied. Martensite/bainite and a small amount of film-like retained austenite complex phase were obtained after the new heat treatment. The results showed that the martensite and retained austenite decreased while bainite increased in the low-temperature austenitizing state compared to high-temperature. Fatigue cracks were mainly emerged at grain boundaries due to quenching stress con- centration at the coarsened grain boundaries of high temperature, while fatigue cracks initiated at the internal inclusions of fine grain. However in the low temperature, the organization was smaller and the fatigue cracks were mainly caused by the internal inclusions. Besides, the fatigue strength in low temperature austenitizing state was higher than high- temperature austenitizing state.

关 键 词：奥氏体化温度 疲劳强度 复相组织 热处理新工艺 

分 类 号：TG1[金属学及工艺—金属学]