金属热处理 ›› 2020, Vol. 45 ›› Issue (1): 254-258.DOI: 10.13251/j.issn.0254-6051.2020.01.049

• 测试与分析 • 上一篇    下一篇

P91钢焊缝650 ℃时效黑线缺陷分析

孙雄1, 刘省2, 王舒涛1, 杨超1, 杨庆旭1, 李夕强1   

  1. 1. 江苏方天电力技术有限公司, 江苏 南京 211102;
    2. 武汉大学 动力与机械学院, 湖北 武汉 430072
  • 收稿日期:2019-06-28 出版日期:2020-01-25 发布日期:2020-04-03
  • 作者简介:孙 雄(1983—),男,高级工程师,硕士,主要从事电网、电站设备失效分析及检测方面的研究,E-mail:18061602018@163.com。

Analysis on black line defects in P91 steel welded joint aged at 650 ℃

Sun Xiong1, Liu Sheng2, Wang Shutao1, Yang Chao1, Yang Qingxu1, Li Xiqiang1   

  1. 1. Jiangsu Frontier Electric Technology Co., Ltd., Nanjing Jiangsu 211102, China;
    2. School of Power and Mechanical Engineering, Wuhan University, Wuhan Hubei 430072, China
  • Received:2019-06-28 Online:2020-01-25 Published:2020-04-03

摘要: 将P91钢焊缝在650 ℃分别时效210、1000、3000和5000 h,采用扫描电镜-X射线能谱分析(SEM-EDS)和复相分离技术(MPST)研究了焊缝黑线/正常组织区域的合金元素(Cr、Mo)的分布变化以及M23C6体积分数变化。结果表明,焊缝黑线缺陷区域组织由δ-铁素体和周边析出相M23C6组成,黑线组织上有显微裂纹和显微孔洞;黑线组织区域的Creq较大,促进了δ-铁素体的生成;随着时效时间的延长,黑线组织区域基体中贫Cr较正常区域严重,M23C6相所占体积分数更多,且颗粒更易粗化。

关键词: P91钢, 焊缝, 黑线缺陷, M23C6

Abstract: P91 steel welded joints were aged at 650 ℃ for 210, 1000, 3000 and 5000 h, respectively. The variation of both the Cr, Mo distribution and the M 23 C 6 volume fraction were investigated along the welding “black line” defect and in the normal microstructure area by using SEM-EDS and MPST (multiphase separation technique). The results show that the microstructure of“black line” defect zone is composed of δ-ferrite and precipitated M 23 C 6 , and some micro cavities and cracks can be found in the “black line”. Cr eq is higher and promotes δ-ferrite formation in the “black line” zone. The depletion of Cr, the volume fraction and the coarsening of M 23 C 6 in the “black line” zone is severer than normal level with the increase of aging time.

Key words: P91 steel, welded joint, black line defect, M23C6 phase

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