超快冷工艺下X80管线钢的DWTT裂纹扩展行为

发布时间：2018-04-16 09:36

本文选题：材料的组织、结构、缺陷与性能 + 超快冷工艺　；参考：《材料研究学报》2017年10期

【摘要】：用OM、SEM以及EBSD技术研究了超快冷工艺制备的18.4 mm X80管线钢的微观组织及晶体学取向,用SEM观察和分析了DWTT断口的表面形貌和裂纹扩展行为,并讨论了超快冷改善管线钢止裂性能的作用机制。结果表明,用超快冷工艺制备的X80管线钢的组织为AF+CB+M/A岛,其中AF组织大约占83%,CB大约占17%,组织的有效晶粒尺寸大约为3.5μm,大角晶界百分比大约为40.9%;在DWTT断裂过程中,实验钢中较大比例的AF和细小M/A岛减小了有效晶粒尺寸,提高了材料的止裂性能。超快冷提高管线钢止裂性能作用机制为:超快冷促进了AF形成,提高了细小弥散分布的M/A岛含量,弱化了AF相变过程中变体的选择,进而降低了有效晶粒尺寸,提高了大角晶界密度,改善了材料的止裂性能。
[Abstract]:The microstructure and crystallographic orientation of 18.4 mm X80 pipeline steel prepared by ultrashort cooling were studied by OMSEM and EBSD. The surface morphology and crack propagation behavior of DWTT fracture were observed and analyzed by SEM.The mechanism of ultra-quick cooling to improve the cracking resistance of pipeline steel is also discussed.The results show that the microstructure of X80 pipeline steel prepared by ultrafast cooling process is AFCB / M / A island, in which AF structure is about 83% and CB is about 17, the effective grain size of microstructure is about 3.5 渭 m, and the percentage of large angle grain boundary is about 40.9g.The larger proportion of AF and the fine M / A island in the experimental steel reduced the effective grain size and improved the crack arrest property of the material.The mechanism of ultra-fast cooling to improve the cracking performance of pipeline steel is as follows: Ultra-fast cooling promotes AF formation, increases the content of small dispersed M / A island, weakens the selection of variants in the process of AF transformation, and then reduces the effective grain size.The density of large angle grain boundary is increased, and the crack arresting property of the material is improved.
【作者单位】：东北大学轧制技术及连轧自动化国家重点实验室;首钢股份迁安钢铁有限公司;
【基金】：国家科技支撑计划(2012BAF04B01) 国家自然科学基金(51504063)~~
【分类号】：TG142.1

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