研究了感应加热淬火工艺参数对轮毂轴承法兰内圈淬火硬化层和组织的影响。结果表明,随着感应加热总能量的提升,淬硬区宏观轮廓逐渐增大,淬硬层深度加深;内圈淬硬区表层及次表层正常组织为细针马氏体+板条马氏体,淬火加热总能量过高会导致表层过热而形成粗针马氏体,甚至过烧;过渡区正常组织为细针马氏体及少量的铁素体+屈氏体,淬火加热总能量过低会导致过渡区形成大量的屈氏体组织,同时残留铁素体量也会增多。感应淬火加热功率180 k W,加热时间5.4 s为最佳的工艺参数。
In this work, the influence of sub-zero Celsius treatment and tempering on the mechanical and thermal stability of retained austenite in bearing steel were assessed by tensile test and DSC. Compared with traditional quenched and tempered treatment, sub-zero Celsius treatment obviously decreases the volume fraction of retained austenite. Moreover,the mechanical stability of retained austenite was enhanced due to the accumulation of compressive stresses in retained austenite after sub-zero Celsius treatment and tempering. Meanwhile, the morphology of retained austenite changed from film-like to blocky with austenitization temperature increasing, and the mechanical stability of film-like retained austenite is higher than that of blocky one. The DSC results showed that the activation energy of retained austenite decomposition slightly increased through sub-zero Celsius treatment and tempering. This result may probably be ascribed to partitioning of carbon during tempering. However, the temperature at which retained austenite starts to decompose is unchanged.
Xiao-Hui LuWei LiCheng-Lin WangHong-Shan ZhaoXue-Jun Jin
