Sollac

Usinor

Arcelormittal

Mohamed Bouzekri

Colin Scott

Michel Faral

Eric Thieblemont

Pascal Gobez

A hot-rolled austenitic iron/carbon/manganese steel sheet is provided. The strength of which is greater than 900 MPa, the product (strength (in MPa)&#xd7;elongation at fracture (in %)) of which is greater than 45000 and the chemical composition of which includes, the contents being expressed by weight 0.5%&#x2266;C&#x2266;0.7%, 17%&#x2266;Mn&#x2266;24%, Si&#x2266;3%, Al&#x2266;0.050%, S&#x2266;0.030%, P&#x2266;0.080% and N&#x2266;0.1%. A remainder of the composition includes iron and inevitable impurities resulting from the smelting. A recrystallized fraction of the structure of the steel is greater than 75%, a surface fraction of precipitated carbides of the steel is less than 1.5% and a mean grain size of the steel is less than 18 microns. A reinforcing element is also provided.

Method of producing austenitic iron/carbon/manganese steel sheets having a high strength and excellent toughness and being suitable for cold forming, and sheets thus produced

The invention concerns a cold-rolled aluminum killed steel sheet, which includes by weight between 0.003 and 0.130% of carbon, between 0.10 and 1% of manganese, between 0.010 and 0.100% of aluminum, between 0.0015 and 0.0140% nitrogen, the remainder being of iron and impurities resulting from the manufacturing, and which has a content of carbon in solid solution (Css) of at least 50 ppm, as well as a method of manufacturing packaging from said sheet.

Cold-rolled aluminum killed steel sheet and method of manufacturing packaging from said sheet

The invention relates to a hot rolled sheet which is made from austenitic iron/carbon/manganese steel and which has a resistance of greater than 900 MPa, whereby: resistance (MPa) x elongation at rupture (%) is greater than 45000. The chemical composition of the inventive sheet comprises the following concentrations expressed as weight: 0.5%=C=0.7%, 17%=Mn=24%, Si=3%, Al=0.05%, S=0.03%, P=0.08%, N=0.1% and, optionally, one or more elements such as Cr=1%, Mo=0.4%, Ni=1%, Ti=0.5%, Nb=0.5%, V=0.5%, Cu=5%, Cu=5%, the rest of the composition comprising iron and impurities resulting from production. According to the invention, the recrystallised fraction of the steel is greater than 75% and the surface fraction of precipitated carbides of the steel is less than 1.5%, the average grain size of the steel being less than 18 micrometers.

The present invention provides a steel sheet with low aluminum content, which includes:

Metal container comprising a steel sheet with low aluminum content

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 mmgreater than 20000 and, in the aged condition, has a percentage elongation A % satisfying the relationship:(640-Rm)/10&#x2266;A %&#x2266;(700-Rm)/l1where Rm is the maximum rupture strength.

Aluminum-killed medium-carbon steel sheet for containers and process for its preparation

The present invention provides a process for manufacturing a steel strip with low aluminum content, which includes:

Process for manufacturing steel strip with low aluminum content for containers

Steel sheet with low aluminum content for containers

Aluminum-killed medium-carbon steel sheet for containers

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 (Ac ) 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.

A process for manufacturing an aluminum-killed low-carbon steel strip by supplying a hot-rolled steel strip having by weight from 0.022 to 0.035% of carbon, from 0.15 to 0.25% of manganese, from 0.040 to 0.70% of aluminum, from 0.0035 to 0.0060% of nitrogen, the remainder being iron and trace impurities, passing the strip through a first cold-rolling, annealing the cold-rolled strip, in which the annealing is continuous using a cycle including: a temperature rise up to a first temperature higher than an onset temperature of pearlitic transformation Ac , holding the strip above the first temperature for a duration of longer than 10 seconds, rapidly cooling the strip to a second temperature below 100&deg; C. at a cooling rate in excess of 100&deg; C. per second, thermally treating the strip at a temperature from 100&deg; C. to 350&deg; C. for a duration in excess of 10 seconds, and cooling the strip to room temperature.

Aluminum-killed low-carbon steel sheet for containers and method for its preparation

Aluminum-killed low carbon steel sheet for containers and method of making

The subject of the present invention is a method of spot resistance welding at least two metal pieces (1, 2). The method consists in pressing the pieces (1, 2) between two electrodes (3, 4), in determining the overall resistance between the electrodes (3, 4), and the contact resistances of each electrode (3, 4) with the piece (1, 2) with which it is in contact, in calculating the contact resistance between the said pieces by the difference between the overall resistance and the sum of the resistances of each piece and of the piece-electrode contact resistances, in determining the actual intensity of the electric welding current, and in adjusting the various welding parameters for the said pieces (1, 2) in order to maintain a constant optimal intensity of the electric welding current. The subject of the present invention is also a welding electrode for implementing the method.

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Rombas, France

Mohamed Bouzekri