Alloys of aluminium have been used for years in high-
performance cars because they are strong enough to
replace steel, but are much lighter. As a result, vehicles
accelerate faster and handle better, advantages that
offset any increase in material and manufacturing costs.
Now aluminium alloys are appearing in mass-market
vehicles, to further boost fuel economy by decreasing
vehicle weight. A 100-kilogram weight reduction
can reduce fuel consumption by half a litre per 100
kilometres of travel.
But, actually forming the alloys into car body parts
places greater demands on lubricants. “As the sheet
material has a higher strength, then the pressure and
temperature also increase. Thus, the lubricant must
have additives that allow the lubricant to perform well
under those conditions,” said Taylan Altan at an Afton
Chemical-sponsored talk during the annual meeting of
the Society of Tribologists & Lubrication Engineers in
Dallas, Texas, U.S.A. in May.
As the director of the Center for Precision Forming in
Columbus, Ohio, U.S.A., Altan researches what is needed
to economically stamp out millions of hoods, door
panels, trunk covers and other car body parts made from
aluminium and other high strength materials. That can
高性能汽车中使用铝合金已有多年,它们有足够的强度来替代钢,但
重量更轻。因此,汽车可以获得更快的加速度,更易操控,这些优势足以
弥补更高的材料和制造成本。现在,铝合金也用于量产的汽车,进一步
通过减重来提高燃油经济性。汽车每减重100公斤,则每百公里油耗可
以下降半升。
但事实上,车身部分采用铝合金对润滑油提出了更高的要求。“由于
板材具有更高的强度,就需要在成型时使用更高的压力和温度,因此,
润滑油中的添加剂需要能在这种工况下正常工作,” 在美国德克萨斯州
达拉斯的摩擦学家和润滑油工程师年度大会中由雅富顿赞助的讨论
中,Taylan Altan说。
美国俄亥俄州哥伦布市的精密加工中心的主任Altan主要研究如何以
经济的方式来冲压成百万的车盖、门板、行李箱盖及其他铝合金或其他
高强度材料的车身部件。由于这些材料的性质,这项工作颇具挑战性。
比如,Al 7075这种铝合金的抗拉强度与钢类似;在应力作用下,发性
断裂前,可以伸长10%。与之相对,钢材则可以延长数倍,在断裂前可以
延展50%以上。因此,用于中等强度的钢材所使用的制造工艺就不适
合高强度材料,因为这些高强度材料在发性断裂前所能承受的延展度
要小许多。
但使用铝材可以使汽车减重约30-40%,Altan说。这在奔驰、宝马、
奥迪这些高档车上可以看出。以平均铝材用量从15%增加到90%,每平
方米可以平均减重95-70公斤。
目前,我们日益急迫地需要更好、更廉价的铝合金车身件制造解决方