X80管线钢待温过程中的析出行为研究  

Research of Precipitation Behavior during Holding Process of X80 Pipeline Steel

作　　者：牛涛[1] 安成钢 姜永文[1] 吴新朗[2] 张彩霞[2] 代晓莉[1] 

机构地区：[1]首钢技术研究院 [2]首钢股份公司迁安钢铁公司

出　　处：《首钢科技》2016年第1期1-5,共5页Shougang Science and Technology

摘　　要：利用应力松弛方法研究了X80管线钢的PTT曲线，结合动力学计算对待温过程中的析出粒子尺寸演变进行模拟，并利用透射电镜研究了X80管线钢在不同待温时间下Nb（C，N）沉淀析出的规律。结果表明，试验用X80管线钢的PTT曲线为典型的C型，析出的鼻尖温度约为900℃，孕育时间约为5s；动力学计算表明，析出粒子的平均直径随着待温时间的延长而明显增加；在X80管线钢的实际生产中，950℃下待温约90s后，60nm的析出粒子比例明显提高，与动力学计算结果基本吻合；固溶铌含量的增加可有效降低晶界迁移率，从而通过溶质拖曳作用抑制再结晶的进行。因此，在不提高温度的情况下，适当缩短待温时间可减少铌在待温过程中的高温析出，从而提高X80管线钢的强韧性。PTT （ Precipitation- Temperature- Time） curve of X80 pipeline steel was obtained by stress relaxation method. The evolution of precipitate particle size during holding process was simulated combined with kinetic calculation, and the precipitation of Nb （C, N） in X80 pipeline steel with different holding time was studied by TEM. The results showed that the shape of FFF curve was typical ＂C＂ type with the nose temperature of 900℃ and incubation time of about 5s. Kinetic calculation results showed that the average particle size increased obviously with the extension of holding time. In the industrial production of X80 pipeline steel, it was observed that after holding for 90 s at 950℃, the proportion of precipitate particles larger than 60 nm increased significantly, which basically agreed with the kinetic calculation results. Grain boundary migration could be slowed down effectively with the increase of dissolved Nb, which inhibited recrystallization by solute drag effect. Therefore, by properly shortening holding time without increasing holding temperature, precipitation of Nb at high temperature could be reduced during holding process, and the strength and toughness of steel could be improved accordingly.

关 键 词：管线钢 待温 析出 再结晶 溶质拖曳 

分 类 号：TG142[一般工业技术—材料科学与工程]