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化学成分和热处理工艺是影响TRIP钢力学性能的关键因素。通过热模拟试验方法研究了不同成分试验钢在临界区退火过程中的微观组织变化规律。结果表明:随着两相区退火温度的升高,铁素体平均晶粒尺寸逐渐减小,铁素体体积分数随着加热温度的升高而降低;残余奥氏体量和其中的C质量分数先随着退火温度的升高而降低,达到一个低谷以后,再随退火温度的升高而升高;在相同的退火温度下,随着Nb的加入,多边形铁素体晶粒尺寸细化,铁素体体积分数逐渐减少;既加Nb又高Si的试验钢钢中残奥数量最多,不加Nb的试验钢中残奥数量最少。TRIP钢试制结果表明,钢带组织类型为典型的TRIP钢组织,多边形铁素体平均晶粒尺寸约8μm,体积分数67%,残余奥氏体体积分数为5.58%,残余奥氏体中C质量分数为1.34%,同时,力学性能也完全满足TRIP590的性能要求。
Chemical composition and heat treatment process are the key factors that affect the mechanical properties of TRIP steel. The microstructure of the test steels with different compositions in the critical region during annealing was studied by means of thermal simulation. The results show that with the increase of annealing temperature in two-phase region, the average ferrite grain size decreases and the volume fraction of ferrite decreases with the increase of heating temperature. The residual austenite content and the C mass The fraction first decreases with the increase of annealing temperature, and then reaches a low level, and then increases with the increase of annealing temperature. At the same annealing temperature, with the addition of Nb, the grain size of polygonal ferrite is refined , And the volume fraction of ferrite decreased gradually. In the test steel containing both Nb and Si, the number of the Paralympic is the highest, and the quantity of the Paralympic in the test steel without Nb is the least. The results of TRIP steel trial showed that the microstructure of the steel strip was a typical TRIP steel. The average grain size of polygonal ferrite was about 8μm, the volume fraction was 67%, the retained austenite volume fraction was 5.58% Score 1.34%, at the same time, mechanical properties also fully meet the performance requirements of TRIP590.