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US 2004/0221928 A1Published application
Aluminum-killed medium-carbon steel sheet for containers and process for its preparation
AssigneeSollac
InventorMohamed Bouzekri
Life of this patent
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Abstract
A process is provided for preparation of an aluminum-killed medium-carbon steel sheet containing by weight from 0.040 to 0.080% of carbon, from 0.35 to 0.50% of manganese, from 0.040 to 0.070% of aluminum, from 0.004 to 0.006% of nitrogen, the remainder being iron and the inevitable trace impurities, wherein 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: (640-Rm)/10≦A %≦(700-Rm)/l1 where Rm is the maximum rupture strength.
Claims20
1-10 (Canceled).
A process comprising
- a first cold-rolling of a hot-rolled steel strip to form a first cold-rolled steel strip, and then
- annealing the first cold-rolled steel strip;
- wherein the hot-rolled steel strip comprises from 0.040 to 0.080% of carbon, from 0.35 to 0.50% of manganese, from 0.040 to 0.070% of aluminum, from 0.0035 to 0.0060% of nitrogen, and the remainder being iron and trace impurities, wherein % is % by weight based on the total weight of the hot-rolled steel strip,
- wherein the annealing is a continuous annealing comprising:
- raising the temperature of the first cold-rolled steel strip to a first temperature higher than an onset temperature of pearlitic transformation Ac1, then
- holding the first cold-rolled steel strip above the first temperature for longer than 10 seconds, and then
- rapidly cooling the first cold-rolled steel strip to a second temperature of below 350° C. at a cooling rate in excess of 100° C. per second,
- to produce an aluminum-killed medium carbon steel strip.
5 more elements
Dependencies are inferred from the claim text.