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
Aluminum-killed medium carbon steel sheets, and the steel sheet stock prepared from it, is useful for manufacturing containers for a variety of food and industrial purposes. High mechanical strength is imparted to steel sheeting when the sheeting is processed through a continuous series of operations including cold-rolling and annealing. Annealing at a temperature maintained above the pearlitic transformation (Ac1) and rapid cooling yields steel sheet of high maximum rupture strength. Improved mechanical properties allows the steel sheet to be used in the manufacture of thin wall containers or containers of novel shape.
Claims20
A process comprising:
- supplying a hot-rolled steel strip comprising 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 0.0035 to 0.0060% of nitrogen, and the remainder being iron and trace impurities,
- passing the strip through a cold-rolling, and
- annealing the cold-rolled strip;
- wherein the annealing step is a continuous annealing using a cycle comprising a temperature rise up to a first temperature higher than an onset temperature of pearlitic transformation Ac1, holding the strip above the first temperature for a duration of longer than 10 seconds, and rapidly cooling the 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 having a hardness from 67 to 76 (HR30T) at an elongation of 5 to 40%.
A process consisting essentially of
- supplying a hot-rolled steel strip comprising 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 0.0035 to 0.0060% of nitrogen, and the remainder being iron and trace impurities,
- passing the strip through a cold-rolling, and
- annealing the cold-rolled strip;
- wherein the annealing step is a continuous annealing consisting essentially of a temperature rise up to a first temperature higher than an onset temperature of pearlitic transformation Ac1, holding the strip above the first temperature for a duration of longer than 10 seconds, and rapidly cooling the 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 having a hardness of from 67 to 76 (HR30T) at an elongation of 5 to 40%.
Dependencies are inferred from the claim text.