加热速度对T91铁素体耐热钢奥氏体形成的影响

Effect of heating rate on the austenization process of T91 ferritic heat-resistant steel

采用高精度差分膨胀仪对不同加热速度（10～6000K／min）下T91铁素体耐热钢的奥氏体形成动力学规律进行了系统研究．研究表明：加热速度显著影响191钢的奥氏体形成开始温度Ac1、结束温度Ac3、相变速率及淬火后的组织．加热速度愈大，Ac1和Ac3温度愈高，奥氏体相变速率愈快，奥氏体形成温度区间愈窄；相对较慢和较快的加热速度对淬火后的组织都有不利的影响．

The influences of heating rate on the austenization process of T91 ferritic heat-resistant steel were systematically explored by high-resolution differential dilatometer in a wide range of 10 - 6000 K/rain during continuous heating. It is found that the applied heating rate has a significant effect on the Ac1 temperature for the onset of austenization, the Ac3 temperature for the end of austenization, the formation rate of austenite and the final microstructure after quenching. Thus determined temperatures of Ac1 and Ac3 increase with the increasing heating rate. For the specimen lastly heated, the temperature range needed for austenization decreases. In addition, the rapid heating rate leads to a high formation rate of austenite and thus a short period for the whole austenization process. Both the slow and fast heating rates have bad influence on the quenched mierostructure.