Mechanism of Weld Solidification and Behavior of its Structure (Report 3)

DOI

Bibliographic Information

Other Title
  • 溶接凝固機構とその組織の特性(第3報)
  • Crystallographic Anisotropy of Columnar zone in Aluminum Weld Metal
  • アルミニウム溶接金属の柱状晶城の結晶学的異方性

Abstract

By x-ray diffraction technique preferred orientation of columnar zone in TIG-arc welded metal has been investigated for commercially pure aluminum (1S and 2S) 1 mm thick sheets. Conclusions obtained are as follows:<BR>(1) The preferred orientation of the columnar zone in the weld metals which have been welded in the welding speeds of 250 to 1500 mm/min is seen to be [100] fiber texture as in castings.<BR>(2) The fiber texture is usually formed near the fusion boundary in the weld metal irrespective of the welding speed.<BR>(3) The direction of the fiber axis follows that of the maximum temperature gradient as far as the latter changes gradually as the growth proceeds inward in like elliptical shaped puddle. This is because of the competitive growth of the columnar crystals which have been originated epitaxially at the fusion boundary and the growth of the stray crystals which have been newly originated inside the weld metal.<BR>However the direction of the fiber axis can not follow the direction of the maximum temperature gradient when the latter changes abruptly as is seen at the weld center of tear-dropped shaped puddle.<BR>(4) In elliptical shaped puddle the angle between the direction of the fiber axis and the welding direction changes from nearly 90 degrees at the fusion boundary to 0 at the weld center as the growth proceeds inward.<BR>On the other hand in tear-dropped shaped puddle the angle is maintained at nearly 90 degrees from the fusion boundary to the weld center.<BR>(5) The spread of the direction of the fiber axis is expected within 20 to 60 degrees irrespective of the welding speed.<BR>(6) From metallographic observation regarding the origination of the stray crystal it is recognized that the growing direction of the subgrain in the stray crystal accords with the normal to the weld ripple, while that in columnar crystal for which the new stray crystal has been substituted considerably deviates.

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Details 詳細情報について

  • CRID
    1390282681479039488
  • NII Article ID
    130003763130
  • DOI
    10.2207/qjjws1943.39.11_1180
  • ISSN
    18837204
    00214787
  • Text Lang
    ja
  • Data Source
    • JaLC
    • Crossref
    • CiNii Articles
  • Abstract License Flag
    Disallowed

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