船板钢CCT曲线的测定与分析

Measurement and analysis of CCT curves of ship plate steel

利用Gleeble3500热模拟试验机对船板用钢进行模拟试验,采集温度-膨胀量曲线,并结合金相法、硬度法绘制出试验材料的CCT曲线。分析CCT图和试验钢显微组织照片,得出不同冷却速度下该钢的组织转变情况。随着冷却速度的逐渐增大,试验钢的组织由多边形铁素体、准多边形铁素体逐步向粒状贝氏体、贝氏体铁素体的转变,同时显微硬度也随冷速的升高呈明显的上升趋势。

Simulated experiment was carried out on a ship plate steel by means of Gleeble3500 hot simulation experiment machine,and the volume expansion data vs temperature were collected.Combined with the metallographic analysis and hardness test,the CCT curves of the ship plate steel were obtained.According to the CCT curves and the microstructures under different cooling rates,the phase transformation of the ship plate steel under different cooling rates was determined.With the increase of cooling rate,the microstructure of the steel is varied from the polygonal ferrite,quasi polygonal ferrite gradually to granular bainite and bainite ferrite transformation.And the microhardness is obviously increased with the cooling rate.