8CrV锯片钢奥氏体连续冷却相变规律研究

Study on Continuous Cooling Transformation of Austenite for 8CrV Saw Blade Steel

利用Gleeble3500型热模拟试验机研究了8CrV锯片钢的奥氏体连续冷却相变规律，并绘制了CCT曲线。研究结果表明，8CrV锯片钢的临界相变温度Acl、Arl、Arcm和Ms分别为755，779，685，705，177℃；8CrV锯片钢的CCT曲线分为2个区，高温相变区和低温相变区，而无中文相变区。其中，高温相变区的相变产物主要为先共析渗碳体和珠光体，低温相变区的相变产物主要为马氏体变区；冷却速度对8CrV锯片钢的奥氏体相变过程及组织有较大影响，随着冷却速度的增加，先共析渗碳体和珠光体的含量逐渐减少，马氏体含量逐渐增加；8CrV锯片钢的淬透性优异，在冷却速度为，后加3℃／s时即出现马氏体组织，其临界淬火速度为20℃／s。

The continuous cooling phase transformation law of 8CrV saw blade steel was studied by the Gleeble 3500 thermal simulation test machine, and the corresponding CCT curve was drawn. The results showed that the critical transition temperatures of Acl, Accm, Arl, Arcm and Ms were 755, 779, 685, 705 and 177 ℃. The CCT curves were divided into two zones, which were the high temperature phase transition zone and low temperature phase transition zone, while there was no medium temperature phase transition zone. The main products of high temperature phase transition zone were proeutectoid cementite and pearlite, and low temperature phase transition zone was martensitic transition. The cooling rate had great effects on the austenite transformation process and microstructure. With the increase of cooling rate, the contents of proeutectoid cementite and pearlite decreased and martensite increased gradually. The 8CrV saw blade steel had excellent hardenability. The martensite arose when cooling rate reached 3 ℃/s and the critical quenching speed was 20 ℃/s.