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大厚度NiCrFe-7熔化焊焊缝微裂纹

吴栋, 董文超, 鲁艳红, 侯冬冬, 张茂龙, 陆善平

吴栋, 董文超, 鲁艳红, 侯冬冬, 张茂龙, 陆善平. 大厚度NiCrFe-7熔化焊焊缝微裂纹[J]. 焊接学报, 2023, 44(6): 15-19. DOI: 10.12073/j.hjxb.20220722001
引用本文: 吴栋, 董文超, 鲁艳红, 侯冬冬, 张茂龙, 陆善平. 大厚度NiCrFe-7熔化焊焊缝微裂纹[J]. 焊接学报, 2023, 44(6): 15-19. DOI: 10.12073/j.hjxb.20220722001
WU Dong, DONG Wenchao, LU Yanhong, HOU Dongdong, ZHANG Maolong, LU Shanping. Micro-cracks of the NiCrFe-7 weld metal with large thickness[J]. TRANSACTIONS OF THE CHINA WELDING INSTITUTION, 2023, 44(6): 15-19. DOI: 10.12073/j.hjxb.20220722001
Citation: WU Dong, DONG Wenchao, LU Yanhong, HOU Dongdong, ZHANG Maolong, LU Shanping. Micro-cracks of the NiCrFe-7 weld metal with large thickness[J]. TRANSACTIONS OF THE CHINA WELDING INSTITUTION, 2023, 44(6): 15-19. DOI: 10.12073/j.hjxb.20220722001

大厚度NiCrFe-7熔化焊焊缝微裂纹

基金项目: 国家重点研发计划资助项目(2018YFA0702902)
详细信息
    作者简介:

    吴栋,1988年出生,博士,副研究员;主要从事高性能焊材研制与熔化焊焊缝缺陷控制,发表论文10余篇;Email: wudong@imr.ac.cn

    通讯作者:

    陆善平,研究员,主要从事焊接冶金、特种焊材与焊接工艺研发工作;Email: shplu@imr.ac.cn

  • 中图分类号: TG 401

Micro-cracks of the NiCrFe-7 weld metal with large thickness

  • 摘要: 通过金相显微镜、扫描显微镜和电子背散射衍射方法对一种大厚度NiCrFe-7熔化焊焊缝中的微裂纹进行了表征和机制分析,焊接方法分别为焊条电弧焊(SMAW)和钨极氩弧焊(GTAW). 结果表明,该种热裂纹为沿晶的再热裂纹,其形成是由于焊接热影响区在高温下发生应力松弛现象,导致晶界大尺寸MC型碳化物和氧化物处出现应力集中,造成裂纹沿这些颗粒内部或界面开裂. 相比于GTAW工艺,SMAW工艺的焊缝中存在大量氧化物,造成SMAW焊缝再热裂纹倾向高于GTAW焊缝,进而导致前者焊缝弯曲性能不符合国家标准要求. 通过此研究,建议采用保护气效果更佳的GTAW工艺.
    Abstract: Micro-cracks in a NiCrFe-7 weld metal with large thickness were characterized and analyzed by metallographic microscopy, scanning microscopy, and electron backscatter diffraction. Two kinds of welding methods, shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW), were applied in our study. The results showed that the crack was a kind of reheating crack along the grain boundaries in the heat affected zone (HAZ). These cracks were induced by the stress relaxation in the heat affected zone during welding process, which resulted in local stress concentration around the large-size MC carbides and oxides. The cracks nucleated and propagated within these particles or along the interfaces of the particles/matrix. Compared with the GTAW process, there were a large number of oxides in the weld metal of the SMAW process. Therefore, the tendency of reheating cracks in the SMAW was much higher than that of the GTAW, which resulted in the bending properties of the former weld failed to meet the requirements of the national standard. The GTAW process with better effect of protective gas was recommended for the Ni-base weld metal with large thickness.
  • 图  1   GTAW焊缝侧弯后试样金相组织

    Figure  1.   The microstructure of GTAW sample after the bending test

    图  2   SMAW焊缝侧弯后试样缺陷形貌

    Figure  2.   Morphology of the defects in the SMAW sample after the bending test. (a) macrostructure of the weld metal; (b) micro-crack at the grain boundary

    图  3   弯曲前SMAW焊缝中微裂纹分析

    Figure  3.   Analysis of the micro-crack in the SMAW weld metal before bending test. (a) location of the micro-crack; (b) magnification of (a); (c) KAM of the micro-crack showed in Fig. 3a, Fig. 3b; (d) the local orientation of (c)

    图  4   裂纹处氧化物及富Nb、Mo碳化物的元素分布

    Figure  4.   Element distribution of the oxides and carbides located in the micro-crack

    图  5   焊缝内氧化物夹杂分布

    Figure  5.   Oxide distribution within the weld metal. (a) SMAW; (b) GTAW

    表  1   焊缝金属内的O元素、N元素、H元素含量 (质量分数,%)

    Table  1   O, N, H contents in the weld metals

    焊接工艺ONH
    SMAW0.0840.0190.000 92
    GTAW0.008 00.0100.000 59
    下载: 导出CSV
  • [1] 刘鸣宇, 张斌, 吴义党. CPR1000反应堆压力容器径向支撑块焊接质量的控制[J]. 金属加工(热加工), 2011, 18: 62 − 64.

    Liu Mingyu, Zhang Bin, Wu Yidang. Control of welding quality of radial support in CPR1000 reactor pressure vessels[J]. Metal Working, 2011, 18: 62 − 64.

    [2]

    Wei X, Xu M, Wang Q, et al. Effect of local texture and precipitation on the ductility dip cracking of ERNiCrFe-7A Ni-based overlay[J]. Materials design, 2016, 110: 90 − 98.

    [3]

    Mo W L, Lu S P, Li D Z, et al. Effects of filler metal composition on the microstructure and mechanical properties for ER NiCrFe-7 multi-pass weldments[J]. Materials Science & Engineering:A, 2013, 582: 326 − 337. doi: 10.1016/j.msea.2013.06.038

    [4]

    Mo W L, Lu S P, Li D Z, et al. Effects of filler metal composition on inclusions and inclusion defects for ER NiCrFe-7 weldments[J]. Journal of Materials Science & Technology, 2013, 29(5): 458 − 466.

    [5]

    Zheng L, Schmitz G, Meng Y, et al. Mechanism of intermediate temperature embrittlement of Ni and Ni-based superalloys[J]. Critical Reviews in Solid State and Materials Sciences, 2012, 37(3): 181 − 214. doi: 10.1080/10408436.2011.613492

    [6]

    Wu D, Li D Z, Lu S P. Microstructures and intermediate temperature brittleness of newly developed Ni-Fe based weld metal for ultra-supercritical power plants[J]. Materials Science and Engineering:A, 2017, 684: 146 − 157. doi: 10.1016/j.msea.2016.12.036

    [7]

    Guo X, He P, Xu K, et al. Microstructural evolution and liquation cracking in the partially melted zone of deposited ERNiCrFe-13 filler metal subjected to TIG refusion[J]. Welding in the World, 2021, 65(5): 825 − 832. doi: 10.1007/s40194-021-01073-8

    [8]

    Heo N H, Chang J C, Kim S J. Elevated temperature intergranular cracking in heat-resistant steels[J]. Materials Science and Engineering:A, 2013, 559: 665 − 677. doi: 10.1016/j.msea.2012.09.007

    [9]

    Mo W L, Hu X B, Lu S P, et al. Effects of boron on the microstructure, ductility-dip-cracking, and tensile properties for NiCrFe-7 weld metal[J]. Journal of Materials Science & Technology, 2015, 31(12): 1258 − 1267.

    [10]

    Ramirez A J, Lippold J C. High temperature behavior of Ni-base weld metal: Part I. Ductility and microstructural characterization[J]. Materials Science and Engineering:A, 2004, 380(1-2): 259 − 271. doi: 10.1016/j.msea.2004.03.074

    [11]

    Ramirez A J, Lippold J C. High temperature behavior of Ni-base weld metal: Part II - Insight into the mechanism for ductility dip cracking[J]. Materials Science and Engineering:A, 2004, 380(1-2): 245 − 258. doi: 10.1016/j.msea.2004.03.075

    [12]

    Asavavisithchai S, Homkrajai W Wangyao P. Strain-age cracking after postweld heat treatments in Inconel 738 superalloy[J]. High Temperature Materials and Processes, 2010, 29: 61 − 68.

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出版历程
  • 收稿日期:  2022-07-21
  • 网络出版日期:  2023-04-20
  • 刊出日期:  2023-06-24

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