Al-Mg 合金 熔接에서 高溫龜裂感受性에 관한 硏究
- Al-Mg 合金 熔接에서 高溫龜裂感受性에 관한 硏究
- Other Titles
- A Study of Hot Cracking Susceptibility in Al-Mg Alloy Weldments
- Issue Date
- No. 2
- Varestraint Test에 의해서 2Lot의 5083-0 板의 高溫龜裂感受性을 調査하였다. 高溫龜裂은 Fusion Zone과 HAZ에서 結晶粒界를 따라 발생되어 傳播하는 것을 觀測하였다. 5083-0 2 Lot의 龜裂感受性 變化를 알아보고 마그네슘含有量差異에 대한 關係와 板의 壓延方向에 대한 熔接方向性의 影響을 調査하였다. 壓延方向에 平行하는 熔接은 壓延方向에 橫斷하는 熔接보다 龜裂感受性이 작았다. 壓延方向에 橫斷하는 熔接에서 Fusion Line 單位길이 當 數많은 HAZ 結晶粒界가 龜裂感受性을 增加시키는 것을 알았다. 熔接實施동안 마그네슘 微細偏析은 最終凝固段階동안에 低融點共晶液體를 形成하고 이 共晶物은 Fusion Zone과 HAZ에서 結晶粒界를 따라 觀察되었다.
The hot cracking susceptibility of two lots of 5083-0 aluminum plate was investigated with the aid of the Varestraint Test. Hot cracks were observed to initiate and propagate along grain boundaries in both the fusion zone and weld heat-affected zone. Significant variation between the cracking sensitivity of the two lots of 5083-0 was found and was related to the difference in Mg content of the lots. In addition, the effect of the orientation of the weld with respect to the rolling direction of the plate was investigated. Welds made parallel to the rolling derection were less crack sensitive than those made transverse to the rolling direction. It was found that the greater number of HAZ grain boundaries per unit length of fusion lime in the welds made transverse to the rolling direction was responsible for this increased cracking sensitivity. Microsegregation of Mg during the welding operation results in the formation of a low melting eutectic liquid during the final stages of solidification. This eutectic material was observed along grain boundaries in both the fusion zone and HAZ.
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