X90管线钢的柔性生产工艺研究

发布时间：2018-01-14 05:29

  本文关键词：X90管线钢的柔性生产工艺研究　出处：《辽宁科技大学》2016年硕士论文　论文类型：学位论文

  更多相关文章： X90管线钢 奥氏体晶粒 针状铁素体 控轧控冷工艺

【摘要】：“十二五”以来我国能源战略的调整推动了石油、天然气工业的全面发展。“西气东输”工程中我国已经掌握了X70和X80管线技术,为进一步提效降本,管线钢的升级换代是必然趋势,因此有必要对X90管线钢进行更多的实验研究。本文从柔性轧制工艺同系列产品工艺优化升级轧制思想出发,以X90管线钢为研究对象,首先在不同加热温度和保温时间条件下进行回溶实验,通过金相观察研究了实验钢显微组织变化规律;通过热模拟实验和金相观察研究了实验钢的连续冷却相变规律和显微组织;在此基础上,通过热模拟实验研究了不同工艺参数对实验钢组织的影响,根据实验结果最优工艺参数范围。主要研究结果如下:1.加热过程中,随着加热温度升高、保温时间延长,X90管线钢的奥氏体晶粒逐渐长大。根据实验数据的非线性回归得出了加热过程中X90管线钢奥氏体晶粒长大模型:综合考虑微合金元素充分固溶和工业生产需要细小均匀的原始奥氏体晶粒两方面,加热温度选择在1140~1200℃范围,保温时间选择30~40 min左右。2.连续冷却实验结果表明,未变形条件下冷速在5~15℃/s之间,主要是粒状贝氏体相变,高于15℃/s后,组织以贝氏体铁素体为主。热变形使CCT曲线向左上方平移,扩大相变温度区间的同时提高了相变的开始温度,细化了组织。在变形条件下,冷速3℃/s时已相变生成了粒状贝氏体,变形促进了针状铁素体形成。随着冷速加快,M-A岛组织含量增加且更细小、弥散,由粒状逐渐变为针状或薄膜状。X90管线钢在控制轧制后,采用不低于20℃/s的冷速可以得到高韧性的针状铁素体,且含有细小M-A岛的理想组织。3.高的粗轧温度不利于组织细化;降低精轧温度有利于得到细小均匀的粒状贝氏体;增大精轧变形量有利于组织细化且可以得到针状铁素体,但精轧变形量过大会使相变温度升高导致出现高温相变产物;终冷温度在350~400℃范围内有利于得到典型的粒状贝氏体组织,终冷温度的降低也有益于组织细化。4.根据实验结果得出优化参数范围:奥氏体化加热温度1140~1200℃,保温30~40 min;在奥氏体再结晶区粗轧,温度1000~1050℃,变形量25%;在奥氏体未再结晶区精轧,温度800~830℃,变形量30~40%;终冷温度在300~350℃范围内,轧后采用20~25℃/s的冷却速度快速冷却。
[Abstract]:Since the 12th Five-Year Plan, the adjustment of China's energy strategy has promoted the overall development of the oil and natural gas industry. In the "West-to-East Gas Transmission" project, China has mastered the X70 and X80 pipeline technologies to further improve the efficiency and reduce the cost. The upgrading of pipeline steel is an inevitable trend, so it is necessary to do more experimental research on X90 pipeline steel. Taking X90 pipeline steel as the research object, the resolution experiment was carried out under different heating temperature and holding time, and the microstructure of the experimental steel was studied by metallographic observation. The continuous cooling phase transformation and microstructure of the experimental steel were studied by thermal simulation and metallographic observation. On this basis, the influence of different process parameters on the structure of experimental steel was studied by thermal simulation experiment, and the optimal range of technological parameters was obtained according to the experimental results. The main results were as follows: 1. During heating process. With the increase of heating temperature, the holding time is prolonged. The austenitic grain growth model of X90 pipeline steel during heating is obtained by nonlinear regression of experimental data. Both the solid solution of microalloyed elements and the need of fine and uniform primary austenite grains in industrial production are considered. The heating temperature is in the range of 1 140 ~ 1 200 鈩，

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