Abstract: According to the applied characteristics of X70 pipeline steel with hydrogen sulfide corrosion resistance, the technical ideas of low carbon, ultra-low sulfur, ultra-low phosphorus and controlled Mn content are used to control the number and shape of MnS inclusions, as well as dendritic segregation and center segregation of casting blank. Through controlled rolling and cooling experiment in laboratory, the effects of various finishing temperatures and final cooling temperatures on the microstructure and performance are analyzed. The experiment results show that, with finishing rolling at 820 ℃ or 840 ℃,the microstructure of quasi-polygonal ferrite + granular bainite can be obtained, with the decrease of finishing temperature, grain size decreases ； with the decrease of coiling temperature, the content of granular bainite increases. Based on the experiment results, the industrial production plan is determined, and the trial production has been completed. The experiment results show that, with finishing rolling at 820 ℃. and coiling at 400℃, the product with microstructure of quasi polygonal ferrite + granular bainite can be obtained, it shows excellent comprehensive performance, the anti-HIC sensitivity is 0, and the anti-SSCC performance is not invalid.

摘要： 根据抗H2S腐蚀X70管线钢的使用特点,采用低碳、超低硫、超低磷、控制Mn含量的技术思路,以控制MnS夹杂物数量和形态、铸坯的枝晶偏析与中心偏析。通过实验室的控轧控冷试验,分析了不同终轧温度和终冷温度对组织和性能的影响,试验结果表明,终轧温度为820℃和840℃时,均可获得准多边形铁素体+粒状贝氏体组织,随着终轧温度的降低,晶粒细化;随着终冷温度的降低,粒状贝氏体含量增加。通过实验室研究结果,确定了工业生产方案,并完成了工业试制。试验结果表明,在820℃终轧,400℃卷取可以获得组织为准多边形铁素体+粒状贝氏体、综合性能优良的产品,其抗HIC敏感测试为0,抗SSCC性能未失效。

关键词: 抗AS腐蚀X70管线钢, 控轧控冷, 组织, 性能