| 摘要: |
| 利用光学显微镜、电子背散射衍射(EBSD)、落锤试验机等检测方法,对5种轧制工艺试制的大壁厚大口径高强韧X80M管线钢进行了金相组织、有效晶粒度、晶界特性、相分析及落锤撕裂试验(DWTT)性能的对比分析。结果表明,粗轧采用低温轧制,并保证道次压下率及轧后充分再结晶,可以减小奥氏体再结晶晶粒尺寸、提高奥氏体再结晶晶粒均匀性；精轧采用较小道次变形并充分回复后再变形的“回复-变形”的轧制方式,可以提高{112}取向晶粒数量、细化有效晶粒尺寸、增加大角度晶界比例、减少粗大马奥岛的数量和尺寸。采用该粗轧和精轧工艺,壁厚为30.8 mm、管径为1 422 mm的X80M管线钢-20 ℃温度下的全厚度DWTT性能达到94%,高于85%的工程应用验收要求。 |
| 关键词: 管线钢 落锤撕裂试验 控制轧制 微观组织 再结晶 回复 |
| DOI：10.11951/j.issn.1005-0299.20210334 |
| 分类号:TG355.5 |
| 文献标识码:A |
| 基金项目:湖南省科技计划项目(2018XK2301). |
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| Experimental study on DWTT performance of large-diameter thick-wall X80M pipeline steels by controlled rolling processes |
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ZHOU Wenhao
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(Technology and Quality Department, Hunan Valin Xiangtan Iron and Steel Co., Ltd., Xiangtan 411101, China)
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| Abstract: |
| The microstructure, effective grain size, grain boundary characteristics, phase analysis, and drop weight tear test (DWTT) performance of X80M pipeline steels with thick wall, large diameter, and high strength and toughness produced by five kinds of rolling processes were compared and analyzed by detection methods of optical microscopy, electron back-scatter diffraction (EBSD), and drop weight tear testing. Results show that during the roughing process, the austenite recrystallization grain size was reduced and the austenite recrystallization grain uniformity was improved through low temperature rolling with high pass reduction rate and sufficient recrystallization after rolling. While during the finishing process, the number of {112} oriented grains was developed, the effective grain size was refined, the proportion of large angle grain boundary was increased, and the number and size of coarse martensite-austenite islands were reduced when using the “recovery-deformation” rolling method, which had smaller pass deformation and full recovery before the next deformation. By using the roughing and finishing process, the full-thickness DWTT property of X80M pipeline steel with wall thickness of 30.8 mm and pipe diameter of 1 422 mm reached 94% at -20 ℃, which was higher than the acceptance requirement of 85% for engineering application. |
| Key words: pipeline steel drop weight tear test controlled rolling microstructure recrystallization recover |
