超快冷下X70管线钢热轧工艺及显微组织

发布时间：2018-05-08 19:20

  本文选题：超快冷 + X管线钢　； 参考：《东北大学学报(自然科学版)》2015年11期

【摘要】：研究了14.2 mm X70管线钢轧后经超快冷+层流冷却、层流冷却两种冷却制度后的显微组织及力学性能,讨论了超快冷+层流冷却下实验钢强韧化机制.结果表明:两种冷却制度下实验钢力学性能均满足API SPEC 5L X70要求,超快冷+层流冷却下实验钢强度、塑性及韧性较高,综合力学性能良好;不同冷却制度下显微组织均为贝氏体铁素体+针状铁素体+M-A岛混合组织,其中超快冷+层流冷却下针状铁素体、M-A岛组织更加细化;超快冷+层流冷却下实验钢主要强韧化机制为细晶强化与纳米析出强化;实验钢理想轧后冷却工艺为:820~840℃终轧+超快冷至450~500℃+层流冷却至350~400℃+卷取.
[Abstract]:The microstructure and mechanical properties of 14.2 mm X70 pipeline steel after ultra-fast laminar cooling and laminar cooling were studied. The strengthening and toughening mechanism of experimental steel under ultra-fast laminar cooling was discussed. The results show that the mechanical properties of the experimental steels under two cooling systems meet the requirements of API SPEC 5L X70, and the strength, ductility and toughness of the experimental steels under ultra-fast laminar cooling are high, and the comprehensive mechanical properties are good. The microstructure of M-A island is mixed with bainitic ferrite acicular ferrite under different cooling conditions, and the microstructure of acicular ferrite M-A island is more fine under ultra-fast laminar cooling. The main strengthening and toughening mechanisms of the experimental steel under ultra-fast laminar cooling are fine grain strengthening and nano-precipitation strengthening, and the ideal cooling process for experimental steel after rolling is as follows: final rolling at 820 ~ 840 鈩，

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