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US 6,398,887 B1Granted
Aluminum-killed low carbon steel sheet for containers and method of making
AssigneeSollac
InventorMohamed Bouzekri
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Abstract
The object of the invention is an aluminum-killed low-carbon steel sheet comprising by weight between 0.022 and 0.035% of carbon, between 0.15 and 0.25% of manganese, between 0.040 and 0.070% of aluminum, between 0.004 and 0.006% of nitrogen, the remainder being iron and the inevitable trace impurities. The steel contains carbon in free state, a grain count per mm2 greater than 20000 and, in the aged condition, has a percentage elongation A% satisfying the relationship: (670−Rm)/14≦A%≦(720−Rm)/17 where Rm is the maximum rupture strength.
Claims9
A process for manufacturing an aluminum-killed low-carbon steel strip for containers in which:
- a hot-rolled steel strip is supplied which contains by weight between 0.022 and 0.035% of carbon, between 0.15 and 0.25% of manganese, between 0.040 and 0.070% of aluminum, between 0.0035 and 0.0060% of nitrogen, the remainder being iron and the inevitable trace impurities,
- the strip is passed through a first-cold-rolling,
- the cold-rolled strip is subjected to annealing, and
- a secondary cold-rolling is performed if necessary, characterized in that
- the annealing is a continuous annealing in which the cycle comprises a temperature rise up to a temperature higher than the temperature corresponding to the eutectoid of the steel, holding the strip above this temperature for a duration of 10 seconds or longer, and rapidly cooling the strip to a temperature of below 350° C. at a cooling rate in excess of 100° C. per second;
- and
- the annealing does not include overaging.
4 more elements
Dependencies are inferred from the claim text.