390MPa级抗碰撞船体钢的奥氏体连续冷却转变

Continuous cooling transformation of austenite in 390 MPa grade anti-collision hull steel

采用Gleeble-3800热模拟试验机研究了390 MPa级抗碰撞船体钢动态和静态条件下过冷奥氏体连续冷却转变行为,通过测定不同冷速下连续冷却过程的膨胀曲线,结合金相-硬度法绘制试验钢的动态和静态CCT曲线。结果表明:与静态条件相比,动态条件下试验钢的铁素体和珠光体转变的冷速区间由0.1~20℃/s缩小至0.1~10℃/s,贝氏体转变的冷速区间由0.5~40℃/s扩大至0.1~40℃/s,马氏体转变的冷速区间由40℃/s扩大至10~40℃/s。动态CCT曲线较静态CCT曲线整体向左上方移动,即扩大了铁素体和珠光体相变区间,并且缩小了贝氏体和马氏体相变区间。

Continuous cooling transformation behavior of 390 MPa grade anti-collision hull steel under dynamic and static conditions was studied by using Gleeble-3800 thermal simulation testing machine.The dynamic and static CCT curves of the tested steel were drawn by measuring the expansion curves of continuous cooling process at different cooling rates and combining with metallographic-hardness method.The results show that compared with the static condition,the cooling rate range of ferrite and pearlite transformation of the tested steel under dynamic condition is reduced from 0.1-20℃/s to 0.1-10℃/s,the cooling rate range of bainite transformation is expanded from 0.5-40℃/s to 0.1-40℃/s,and the cooling rate range of martensite transformation is expanded from 40℃/s to 10-40℃/s.The dynamic CCT curves moves to the upper left compared with the static CCT curves,indicating that the ferrite and pearlite phase transformation region enlarged and the bainite and martensite phase transformation region reduced.