Casting of non-ferrous metals
View Patent ↗A method of continuous casting non-ferrous alloys which includes delivering molten non-ferrous alloy to a casting apparatus. The casting apparatus rapidly cools at least a portion of the non-ferrous alloy at a rate of at least about 100° C. thereby solidifying an outer layer of the non-ferrous alloy surrounding an inner layer of a molten component and a solid component of dendrites. The dendrites are altered to yield cast product exhibiting good resistance to cracking.
1. A method of continuously casting molten metal into a metal product comprising the steps of:
providing non-ferrous molten metal to a pair of spaced apart advancing casting surfaces;
solidifying the molten metal on the casting surfaces while advancing the metal between the casting surfaces to produce solid metal outer layers adjacent the casting surfaces and a semi-solid inner layer containing dendrites of the metal between the solid metal outer layers;
breaking the dendrites in the inner layer;
solidifying the semi-solid inner layer to produce a solid metal product comprised of the inner layer and the outer layers; and
withdrawing the solid metal product from between the casting surfaces.
2. The method of claim 1 wherein the casting surfaces are surfaces of a roll or belt.
3. The method of claim 1 wherein the casting surfaces approach each other and said step of solidifying the semi-solid layer is completed at a position of minimum distance between the casting surfaces.
4. The method of claim 3 wherein the casting surfaces are surfaces of rotating rolls with a nip defined therebetween, such that completion of said solidifying step occurs at the nip.
5. The method of claim 3 wherein the casting surfaces are surfaces of belts traveling over rotating rolls, the rolls defining a nip therebetween, and completion of said solidifying step occurs at the nip.
6. The method of claim 4 wherein the product exits the nip at a rate of about 25 to about 400 feet per minute.
7. The method of claim 4 wherein the product exits the nip at a rate of at least about 100 feet per minute.
8. The method of claim 6 wherein the force applied by the rolls to the metal advancing therebetween is a maximum of about 300 pounds per inch of width of the product.
9. The method of claim 1 wherein the product comprises a metal strip having a thickness of about 0.06 to about 0.25 inch.
10. The method of claim 1 wherein the metal is an alloy of aluminum.
11. The method of claim 1 wherein the metal is an alloy of magnesium.
12. The method of claim 1 wherein the metal is an alloy of titanium.
13. The method of claim 1 wherein the composition of the solidified inner layer of metal is different from the composition of the other layers of metal.
14. The method of claim 1 further comprising a step of in-line rolling the withdrawn solid metal product.
15. The method of claim 1 further comprising a step of off-line rolling the withdrawn solid metal product.
16. The method of claim 1 wherein the metal product comprises automotive sheet product.
17. The method of claim 1 wherein the metal product comprises aerospace sheet product.
18. The method of claim 1 wherein the metal product comprises beverage can body stock.
19. The method of claim 1 wherein the metal product comprises beverage can end stock or beverage can tab stock.