Large-sized sectional material used in sub-way carriage has the feature of complex profile,big circumscribed circle and large basal area.

• 地铁车辆用大型铝合金型材一般断面形状较复杂,壁厚相差悬殊,断面积及外接圆大,且宽厚比较大,是生产难度很大的一类型材。