摘要
作为管道运输材料的X80M,其拉伸强度、低温DWTT性是关键控制难点,也关系到管道在未来服役过程中的运行安全性。利用拉伸试验机、光学显微镜、扫描电镜及落锤撕裂试验机,研究了X80M管线钢的低温落锤性能、抗拉强度以及卷取温度下的组织性能演变。结果显示:X80M钢的芯部组织出现粗大的QF及碳化物团簇,导致低温DWTT性能下降。适当降低卷取温度、增加层冷水量以及增大中间坯厚度,可以将-20℃低温DWTT剪切面积控制在95%以上,显著改善DWTT性能;在高温段加热时,若加热时间过长,Nb元素的固溶量增加,导致X80M钢的抗拉强度超过设计要求,通过严格控制加热时间及加热温度,X80M钢的抗拉强度稳定维持在720 MPa以下;卷取温度为350℃时钢的组织为均匀的AF及弥散分布的M/A岛,强韧性均较良好,因此选取350℃为最适宜的卷取温度。
As a material for pipeline transportation,the tensile strength and low-temperature DWTT property of X80M are key control difficulties and also related to the operational safety of the pipeline during its future service.The low-temperature drop weight performance,tensile strength performance and microstructure and property evolution of X80M pipeline steel at different coiling temperatures were studied by using tensile testing machines,optical microscopes,scanning electron microscopes and drop weight tear testing machines.The results show that the core structure of X80M steel presents coarse QF and carbide clusters,leading to a decline in low-temperature DWTT performance.By appropriately reducing the winding temperature,increasing the amount of cold water in each layer and enlarging the thickness of the intermediate billet,the shear area of the-20℃low-temperature DWTT can be controlled at over 95%,significantly improving the performance of the DWTT.When heated in the high-temperature section,if the heating time is too long,the solid solution amount of Nb element increases,causing the tensile strength of X80M steel to exceed the design requirements.By strictly controlling the heating time and temperature,the tensile strength of X80M steel is stably maintained below 720 MPa.When the coiling temperature is 350℃,the microstructure of the steel is uniform AF and diffused M/A islands,with good strength and toughness.Therefore,350℃is selected as the most suitable coiling temperature.
作者
杨玉厚
邢天庆
陈彤
魏梦麒
耿云飞
Yang Yuhou;Xing Tianqing;Chen Tong;Wei Mengqi;Geng Yunfei(Technical Center of Tangshan Iron and Steel Group Co.,Ltd.,Tangshan 063016,Hebei;Quality Management Department of Tangshan Iron and Steel Group Co.,Ltd.,Tangshan 063016,Hebei)
出处
《河北冶金》
2025年第10期60-66,共7页
Hebei Metallurgy
