Study on Microcracks in Multi-pass Weld Metals of Ni-base Alloys(Part 1). Fractography on Microcracks in Ni-base Multi-pass Weld Metals.

DOI 4 Citations

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Other Title
  • Ｎｉ基合金の多層盛溶接金属におけるミクロ割れの研究　（第１報）　Ｎｉ基多層盛溶接金属中のミクロ割れの破面解析
  • Study on Microcracks in Multi-pass Weld Metals of Ni-base Alloys (Part 1)
  • Ni基合金の多層盛溶接金属におけるミクロ割れの研究(第1報)

Abstract

Fractographic investigation of microcracks in a real multi-pass weld metal of Ni-base alloys was carried out in order to find out the factors which caused microcracks in this study.<BR>Two modes of microcracks, viz., liquation crack and ductility-dip crack were observed in reheated zones of weld metal. According to the EDX and AES analyses on fracture surface of these cracks, not only Nb and Mo in microconstituents but also P, Si and Senriched on thefracture surface.<BR>The cross-bead varestraint test was performed in order to make clear the effects of impurity elements such as P, Si and S on hot cracking susceptibility of reheated weld metal of Ni-Cr-Fe ternary alloys. Base metals used were basically 70%Ni-Cr-Fe ternary alloys in which Cr contents were varied from 0 to 20%. P, Si and S contents were independently varied in the ranges of 0.002-0.032%, 0.05-1.02% and 0.001-0.02%, respectively.<BR>Although the liquation cracking susceptibilities of all materials used were too low, they increased with an increase in impurity elements. On the other hand, in the case of ductility-dip cracking, cracking susceptibilities of materials containing S were much higher than those containing P and Si. Especially cracking susceptibilities of Ni-30%Fe and Ni-20%Cr-10%Fe alloys containing 0.007%S were higher than those of Ni-5%Cr-25%Fe and Ni-10%Cr-20%Fe alloys. It followed that the ductility-dip cracking susceptibility of reheated weld metal of 70%Ni-Cr-Fe alloy was affected as a function of interaction of Cr and S contents in weld metal.

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Details 詳細情報について

  • CRID
    1390001204723776768
  • NII Article ID
    130003934276
  • DOI
    10.2207/qjjws.11.102
  • ISSN
    24348252
    02884771
  • Text Lang
    ja
  • Data Source
    • JaLC
    • Crossref
    • CiNii Articles
  • Abstract License Flag
    Disallowed

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