On the properties of 2S slab made by continuous casting

On a largc-sized aluminium slab of 500×830×180mm (about 200kg), the comparison test was made for properties of its upper part (from where the casting was started), middle part and lower part (when the casting was ended). There is some differnce between them from the view-points of micro structure as well as of macro structure, But Almost no difference is seen in such mechanical properties as tensile strength, elongation, hardness and shearing strength. The Knoop ratio is higher in the middle part though sliglhty.Even when the slab is colled-rolled in cross way or one way, no differnce appears in mechanical properties and also in softening curve between the three parts.When deep-drown, the caring in the part from upper part of the slab is slightly different from others under the cold-reduction of 70-80%, whilesuch difference is not seen when the reduction is raised to 92.9%