等温淬火工艺对高硅铸钢残余奥氏体量的影响

Investigation of the Influence of Austempering Processing on Retained Austenite Amount of Austempered High Silicon Cast Steel

采用X射线衍射对高硅铸钢等温淬火热处理后的残余奥氏体量以及残余奥氏体含碳量进行了测定。结果表明,240～400℃等温淬火处理时,在较低的等温温度下,残余奥氏体的含量以及残余奥氏体含碳量较低,随着等温温度的提高,残余奥氏体量以及残余奥氏体含碳量逐渐上升。在贝氏体转变初期,最终组织中残余奥氏体量较少,残余奥氏体含碳量较低;在等温处理时间内,随着等温时间的延长,残余奥氏体量以及残余奥氏体含碳量逐渐增加,在等温60min时达到了最大值,然后减少。

The volume fraction and carbon content of retained austenite in the austempered high silicon cast steel after various austempering combinations were investigated by XRD method. The experiments indicated that the volume fraction and carbon content of retained austenite are low at lower austempering temperatures, and with the increasing of the austempering temperature the volume fraction and carbon content of retained austenite increase gradually within the 240-400℃ of austempering temperature. It has been also found that at the beginning of austempering transformation, the volume fraction and carbon content of retained austenite is relatively low and with the extending of the austempering time, the volume fraction and carbon content of retained austenite increase gradually. Austempering afer 60 minutes the volume fraction and carbon content of retained austenite reache to the maximum values and then decrease with the extending of the austempering time within the austempering time given.