Al-Mg合金汽车材深冲开裂问题的工艺研究

Al-Mg合金因性能良好常用于汽车材料,但加工工艺的不当容易导致产品出现冲压开裂状况。本文证实了临界加工率的存在,并分析其导致材料开裂的原因。临界加工率条件下进行完全再结晶退火(350℃×4h),晶粒尺寸增长至正常尺寸的6倍,同时抗拉强度、延伸率均出现下降,提高退火温度(450℃×4h),材料晶粒增长至原尺寸的10倍,抗拉强度下降约20MPa,延伸率降低4%。高于临界加工率下进行350℃×4h或450℃×4h完全再结晶退火,材料组织与性能基本不产生变化。

Technology Research of Deep-drawing Crack Problem for Al-Mg Alloy Used for Automotive Material

Al-Mg alloy is used as automotive material because of good property, but improper technology may lead to deep-drawing crack. The existence of the critical machining ratio was proved and the reason which caused the crack was analyzed in the paper. Complete recrystallization anncaling（350℃ × 4h） is performed in the condition of critical machining ratio, and the size of the grain will increase by six times as large as that of normal. And the tensile strength,elongation both decrease. When the annealing temperature is in creased （450℃ ×4h）,the size of the grain will increase by ten times as large as that of normal,and the tensile strength decrease by 20Mpa or so, the elongation decease by 4% or so. But, the property and the structure almost remain the same when the complete recrystallization（350℃ ×4h or 450℃ × 411） are conducted in the condition of above the critical ratio.