试样减薄对大壁厚X80级管线钢落锤性能的影响  

Effect of sample thinning on DWTT property of heavy wall X80 steel

作　　者：邵春娟 镇凡 张继明 曲锦波 张磊 SHAO Chun-juan;ZHEN Fan;ZHANG Ji-ming;QU Jin-bo;ZHANG Lei(Jiangsu Shagang Group Co.,Ltd.,Zhangjiagang 215625,Jiangsu,China)

机构地区：[1]江苏沙钢集团有限公司,江苏张家港215625

出　　处：《钢铁研究学报》2020年第6期497-504,共8页Journal of Iron and Steel Research

基　　金：国家重点研发计划资助项目(2017YFB0304900)。

摘　　要：采用金相显微镜和扫描电镜对30.8 mm大壁厚X80管线钢不同减薄方式下DWTT试样截面微观组织和试验断口进行了分析,目的是研究减薄方式对大壁厚管线钢DWTT性能的影响。结果表明,随着试验温度的降低,单边减薄的DWTT性能优于双边减薄,而且双边减薄试样从表面至心部,贝氏体体积分数逐渐降低,多边形铁素体体积分数逐渐升高,晶粒尺寸变大,MA岛由细小的颗粒状变为尺寸较大的链状,且心部伴随着严重的偏析和夹杂。而单边减薄试样从表面至心部组织整体变化不大;裂纹优先沿着消耗能量最低的部位开裂,所以双边减薄试样心部出现比单边减薄试样严重的解理和逆解理断裂。The effect of thinning style on DWTT properties of X80 pipeline steel was investigated by means of DWTT testing,and facture morphology and microstructure were observed using optical microscope(OM)and scanning electron microscope(SEM).The results show that with the decrease of test temperature,the properties of DWTT of single-side thinned sample are better than that of double-side thinned sample.From the surface to center of the double-side thinned sample,the bainitic volume fraction gradually decreases,the polygonal ferrite volume fraction gradually increases,the grain size increases gradually,the morphology of MA islands are changed from a single fine granular into a large particle chain,and microstructure in the center is accompanied by severe segregation and inclusions.However,the microstructure of the single-side thinned sample has little change from the surface to the center of sample.Due to the crack initiation preferentially along the sites with the lowest energy consumption,therefore the brittle cleavage and reverse cleavage fracture are worse in the center of the double-side thinned sample than that of the single-side thinned sample.

关 键 词：落锤性能 单边减薄 双边减薄 裂纹 

分 类 号：TG142.1[一般工业技术—材料科学与工程]