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工业生产中B450NbRE钢冲击韧性不稳定,分析原因在于轧制组织异常,而冶炼时存在稀土收得率不稳定现象,为了研究微量稀土对B450NbRE钢组织和相变的影响,使用真空感应炉冶炼了不同稀土质量分数(0.0010%,0.0046%和0.0160%)的B450NbRE钢,并采用Gleeble-1500热模拟实验机在950℃进行20%和40%的应变,通过对连续冷却过程膨胀数据的测量绘制CCT曲线,结合金相分析研究了稀土对B450NbRE钢组织和相变的影响作用。结果表明,冷却速率小于1℃.s-1时,B450NbRE钢组织以多边形铁素体和贝氏体为主,随着稀土含量的增加,铁素体含量先增加后降低,稀土具有促进多边形铁素体向针状铁素体转变的作用。
In the industrial production, the impact toughness of B450NbRE steel is unstable. The reason for the analysis is that the rolling structure is abnormal, and the yield of rare earth is unstable during smelting. In order to study the effect of trace rare earth on microstructure and phase transformation of B450NbRE steel, vacuum induction furnace is used to smelt B450NbRE steels with different rare earth contents (0.0010%, 0.0046% and 0.0160%) were prepared and subjected to 20% and 40% strain at 950 ° C using a Gleeble-1500 thermal simulation machine. CCT was plotted by measuring the expansion data for continuous cooling Curve, combined with metallographic analysis of rare earth on the microstructure and phase transition of B450NbRE steel. The results show that when the cooling rate is less than 1 ℃ .s-1, the microstructure of B450NbRE steel mainly consists of polygonal ferrite and bainite. With the increase of rare earth content, the ferrite content first increases and then decreases, and rare earth has the effect of promoting polygonal iron The role of the body to acicular ferrite.