• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2024, Vol. 60 ›› Issue (8): 196-203.doi: 10.3901/JME.2024.08.196

• 材料科学与工程 • 上一篇    下一篇

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16MnDR钢焊接接头组织特性及在氢氟酸环境中的腐蚀行为

顾玉芬1, 鲁娜1, 石玗1, 孙青岭2   

  1. 1. 兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室 兰州 730050;
    2. 中核兰州铀浓缩有限公司 兰州 730060
  • 收稿日期:2023-03-04 修回日期:2023-09-15 出版日期:2024-04-20 发布日期:2024-06-17
  • 作者简介:顾玉芬,女,1975年出生,副教授。主要研究方向为焊接自动化及其结构可靠性。E-mail:guyf@lut.cn;石玗(通信作者),男,1973年出生,教授,博士研究生导师。主要研究方向为先进焊接方法、焊接物理及焊接过程控制。E-mail:shiyu@lut.cn
  • 基金资助:
    甘肃省重点研发资助项目(20YF3WA017)。

Microstructure Characteristics of 16MnDR Steel Welded Joint and Its Corrosion Behavior in Hydrofluoric Acid Environment

GU Yufen1, LU Na1, SHI Yu1, SUN Qingling2   

  1. 1. State Key Laboratory of Advanced Processing and Reuse of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050;
    2. China National Nuclear Corporation Lanzhou Uranium Enrichment Co., Ltd., Lanzhou 730060
  • Received:2023-03-04 Revised:2023-09-15 Online:2024-04-20 Published:2024-06-17

摘要: 16MnDR钢中厚板核贫料储罐焊接接头采用脉冲钨极氩弧焊(P-TIG)打底和埋弧焊(SAW)填充及盖面工艺制造。只采用P-TIG焊接的打底层组织为针状铁素体+索氏体,但SAW填充后的打底层发生了组织转变,变为多边形铁素体+蠕虫状屈氏体。通过对焊接接头在0.1 M氢氟酸中的浸泡腐蚀试验发现,SAW填充后的打底层的耐蚀性发生严重退化,其原因是蠕虫状屈氏体极细的片层结构在腐蚀溶液中发生了微电偶腐蚀,从而近表面的屈氏体就相当于一个块状的渗碳体,然后与周边多边形铁素体形成的大阴极小阳极的腐蚀电偶加速了铁素体的腐蚀溶解,进而屈氏体失去支撑,最终松动脱落并在宏观上形成了腐蚀坑。这一发现为核贫料储罐的安全服役奠定了理论基础,为后续工艺的优化设计指明了方向。

关键词: 16MnDR钢, 焊接, 显微组织, 热循环, 腐蚀

Abstract: The welding joint of 16MnDR steel medium thickness plate nuclear lean material storage tank is made by pulse argon tungsten arc welding (P-TIG) for priming and submerged arc welding (SAW) for filling and covering. The bottom layer of P-TIG welding is acicular ferrite + sorbite, but the bottom layer filled by SAW is transformed into polygonal ferrite + vorm-like troostite. Through the welding joint in the 0.1 M hydrofluoric acid immersion corrosion test, the corrosion resistance of root pass after SAW filling degraded seriously was found, the reason is that microgalvanic corrosion occurs between the very fine lamellar structure of worm-like troostite in the corrosion solution, so that the troostite near the surface is equivalent to a massive cementite. Then the formation of corrosion galvanic of big cathode and small anode between worm-like troostite and periphery polygon ferrite accelerated the corrosion dissolution of ferrite, and then troostite loses support, loosens and falls off and finally forms corrosion pits on the macro. This discovery lays a theoretical foundation for the safe service of nuclear lean material storage tank and points out the direction for the optimization design of the subsequent process.

Key words: 16MnDR steel, welding, microstructure, thermal cycle, corrosion

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