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$CO_2$ 레이저 용접한 7N01 Al합금의 미세조직 특징(I) - 완전용입 용접부의 미세조직 -
윤재정,강정윤,김인배,김대업 대한용접접합학회 2001 대한용접·접합학회지 Vol.19 No.4
The effect of welding condition on the microstructures of the weld metal in A7N01 welded by $CO_2$ laser was investigated. The number of ripples was increased with decreasing power and increasing welding speed. In the bead without ripple lines, the subgrain microstructures distribution from the fusion line toward the center of the bead were in the order of cellular, dendritic and equiaxed dendrite. However, in the bead with ripple lines, cellular and dendritic were formed between the fusion boundary and the ripple line. Inaddition, those structures were also observed between the ripple line. Equiaxed dendrites were formed only at the center line region. Cellular and dendritics formed near the ripple line were larger than those formed near the fusion boundary. The cooling rates estimated by the dendrite arm spacing were in the range of 200 to 1150oC/s. Cooling rate was increased with decreasing the power and increasing the welding speed. Mg and Zn segregated at the boundaries of cellulars and dendritics, Mg was segregated more than Zn. The segregation of Mg and Zn decreased with increasing cooling rate. Hardness of the weld metal was lower than that of the base metal in all welding conditions and increased as the cooling rate increased.
윤재정(Jaejung Yun),박동환(Donghwan Park),김근영(Kunyoung Kim) 한국생산제조학회 2011 한국생산제조시스템학회 학술발표대회 논문집 Vol.2011 No.4
With the increase of market demand on cost reduction, simultaneous forming technology, producing componenets by simultaneous deformation of several blank sheets, has been focused as one of the economic forming process minimizing consumption of time and cost. In the current study, simultaneous forming was introduced to the formation of automobile components such as Front side member. Re-design or modularization of the components were performed considering weight reduction and formability.