CounterPressure casting technology in given air pressure to realize filling and solidification for aluminium alloy melt can effectively raise dissolvability of H

+

in aluminium alloy

and restrain the casting from forming pin holes due to the separation out of H

+

during casting solidification. At the same time air pressure can obviously improve adherence effects of casting with cavity so as to make casting get better cooling effects than other methods. As a result

the casting gets a smaller crystal structure

thus densification and mechanical properties are greatly improved. This article expounds the research result of big offset load type wheels

which have special requirements in manufacturing integral aluminium wheels for cars. The result proves that the method can satisfy not only mechanical property of midtrucks

but also the need of polishing and plated wheels which require better casting surfaces.