| 摘要 |
This invention relates to a process for manufacturing Al-Mg alloy sheets with high Mg content for press forming. The composition of an Al-Mg alloy slab consists of 5 to 10 wt.% of Mg, 0.0001 to 0.01 wt.% of Be, totally 0.01 to 0.2 wt.% of one or more than two species out of Mn, Cr, Zr and V, 0.005 to 0.1 wt.% of Ti, or both 0.005 to 0.1 wt.% of Ti and 0.00001 to 0.05 wt.% of B, Fe and Si as impurities respectively with the content restricted to be less than 0.2 wt.%, and the remainders consisting of other inevitable impurities and Al. The maximum grain diameter of the alloy slab is less than 1000 .mu.m. The homogenization conditions of the alloy slab are set such that a temperature for homogenization is in the range of 450 to 540.degree.C and a time for the homogenization is not more than 24 hrs, and the conditions for the hot rolling are set such that a hot mill entrance temperature is in the range of 320 to 470.degree.C and each reduction per pass of at least the initial three times of rolling pass is not more than 3%. This process improves the hot workability of Al-Mg alloy sheets with high Mg content, and cracks are prevented from being generated at the time of hot rolling to improve the productivity. When 0.05 to 0.8 wt.% of Cu is contained in the Al-Mg alloy slab, in addition to the above-mentioned component compositions, the strength and elongation of the resultant alloy sheets can be further improved.
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