軟鋼溶接金属における各種フエライトの転位組織

概要

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Electron microscopic investigation was carried out on dislocation structure of various types of ferrites in as-deposited weld metal of mild steel. Welding processes employed were shielded metal arc welding, CO_2 arc wleding, submerged arc welding and electro-slag welding. Change of weld heat input affected not only the ferrite in size and shape but also its substructure. The microstructures of weld metals consisted of three types of ferrites; proeutectoid ferrites, side plate ferrites and acicular ferrites in all welding processes but electro-slag welding. Acicular ferrite, which occupied the most area contained the rather higher density of dislocation than the other two. Increasing cooling rate tended to cause the decrease of dislocation density in each type of ferrites. Dislocation structure seemed not to be sensitive to welding process, as far as dislocation density was concerned. The dislocation density observed ranged from (10)^9 to (10)^<10>(cm)^2 in all welding processes employed. Effect of cooling rate on the internal stress of each ferrite grain was also studied. The internal stress, which was estimated from radius of curvature of dislocations increased with dislocation density in ferrites.
社団法人溶接学会の論文
1982-04-05