Steel sheet with low aluminum content for containers

Abstract

The present invention provides a process for manufacturing a steel strip with low aluminum content, which includes: hot-rolling a steel strip which includes between 0.050 and 0.080% by weight of carbon, between 0.25 and 0.40% by weight of manganese, less than 0.020% by weight of aluminum, and between 0.010 and 0.014% by weight of nitrogen, the remainder being iron and inevitable trace impurities, to form a strip; subjecting the strip to a first cold-rolling, to form a cold-rolled strip; annealing the cold-rolled strip, to form an annealed cold-rolled strip; optionally, subjecting the annealed cold-rolled strip to a secondary cold-rolling; wherein the annealing is a continuous annealing which includes: raising the temperature of the strip to a temperature higher than the temperature of onset of pearlitic transformation Ac1, holding the strip above this temperature for a duration of longer than 10 seconds, and rapidly cooling the strip to a temperature below 350° C. at a cooling rate in excess of 100° C. per second. Another embodiment of the invention provides a steel strip, produced by the above-mentioned process. Another embodiment of the invention provides a steel sheet with low aluminum content, which includes: between 0.050 and 0.080% by weight of carbon, between 0.25 and 0.40% by weight of manganese, less than 0.020% by weight of aluminum, and between 0.010 and 0.014% by weight of nitrogen, the remainder being iron and inevitable trace impurities, wherein when in an aged condition the sheet includes a percentage elongation A % satisfying the relationship: (750-Rm)/16.5≦A %≦(850-Rm)/17.5 where Rm is the maximum rupture strength of the steel, expressed in Mpa. Another embodiment of the invention provides a container, which includes or is made from the above-mentioned steel sheet.

Dependencies are inferred from the claim text.