Abstract: The invention relates to a hot-rolled steel sheet having a tensile strength greater than 800 MPa and an elongation at break greater than 10%, the composition of which comprises, the contents being expressed by weight: 0.050%?C?0.090%, 1%?Mn?2%, 0.015%?Al?0.050%, 0.1%?Si?0.3%, 0.10%?Mo?0.40%, S?0.010%, P?0.025%, 0.003%?N?0.009%, 0.12%?V?0.22%, Ti?0.005%, Nb?0.020% and, optionally, Cr?0.45%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting, the microstructure of the sheet or the part comprising, as a surface fraction, at least 80% upper bainite, the possible complement consisting of lower bainite, martensite and residual austenite, the sum of the martensite and residual austenite contents being less than 5%.

Abstract: The invention relates to a process for making a hot stamped coated steel sheet product, comprising the steps of pre-coating a steel strip or sheet with aluminum—or aluminum alloy, cutting said pre-coated steel strip or sheet to obtain a pre-coated steel blank, heating the blank in a furnace preheated to a temperature and during a time defined by diagram according to thickness, at a heating rate Vc between 20 and 700° C. comprised between 4 and 12° C./s and at a heating rate Vc? between 500 and 700° C. comprised between 1.5 and 6° C./s, to obtain a heated blank; then transferring said heated blank to a die, hot stamping the heated blank in the die obtain a hot stamped steel sheet product, cooling at a mean rate Vr between the exit of the heated blank from the furnace, down to 400° C., of at least 30° C./s.

Abstract: The invention relates to a process for making a hot stamped coated steel sheet product, comprising the steps of pre-coating a steel strip or sheet with aluminum- or aluminum alloy, cutting said pre-coated steel strip or sheet to obtain a pre-coated steel blank, heating the blank in a furnace preheated to a temperature and during a time defined by diagram according to thickness, at a heating rate Vc between 20 and 700° C. comprised between 4 and 12° C./s and at a heating rate Vc? between 500 and 700° C. comprised between 1.5 and 6° C./s, to obtain a heated blank; then transferring said heated blank to a die, hot stamping the heated blank in the die obtain a hot stamped steel sheet product, cooling at a mean rate Vr between the exit of the heated blank from the furnace, down to 400° C., of at least 30° C./s.

Abstract: Coated steel having a well defined and uniform thickness is useful and advantageous for preparing products by hot stamping. Products prepared by hot stamping such a steel are particularly advantageous when subjected to a subsequent spot welding step.

Abstract: Coated steel having a well defined and uniform thickness is useful and advantageous for preparing products by hot stamping. Products prepared by hot stamping such a steel are particularly advantageous when subjected to a subsequent spot welding step.

Abstract: A manufacturing process of a hot stamped coated part comprising the following successive steps, in this order: providing a hot rolled or cold rolled steel sheet comprising a steel substrate and an aluminium-silicon alloy precoating, the precoating containing more than 50% of free aluminium and having a thickness comprised between 15 and 50 micrometers, then cutting the steel sheet to obtain a precoated steel blank, then heating the blank under non protective atmosphere up to a temperature Ti comprised between Te?10° C. and Te, Te being the eutectic or solidus temperature of the precoating, then heating the blank from the temperature Ti up to a temperature Tm comprised between 840 and 950° C. under non protective atmosphere with a heating rate V comprised between 30° C./s and 90° C.

Abstract: The invention relates to a process for making a hot stamped coated steel sheet product, comprising the steps of pre-coating a steel strip or sheet with aluminium-or aluminium alloy, cutting said pre-coated steel strip or sheet to obtain a pre-coated steel blank, heating the blank in a furnace preheated to a temperature and during a time defined by diagram according to thickness, at a heating rate Vc between 20 and 700° C. comprised between 4 and 12° C./s and at a heating rate Vc? between 500 and 700° C. comprised between 1.5 and 6° C./s, to obtain a heated blank; then transferring said heated blank to a die, hot stamping the heated blank in the die obtain a hot stamped steel sheet product, cooling at a mean rate Vr between the exit of the heated blank from the furnace, down to 400° C., of at least 30° C./s.

Abstract: The invention relates to a process for making a hot stamped coated steel sheet product, comprising the steps of pre-coating a steel strip or sheet with aluminium- or aluminium alloy, cutting said pre-coated steel strip or sheet to obtain a pre-coated steel blank, heating the blank in a furnace preheated to a temperature and during a time defined by diagram according to thickness, at a heating rate Vc between 20 and 700° C. comprised between 4 and 12° C./s and at a heating rate Vc? between 500 and 700° C. comprised between 1.5 and 6° C./s, to obtain a heated blank; then transferring said heated blank to a die, hot stamping the heated blank in the die obtain a hot stamped steel sheet product, cooling at a mean rate Vr between the exit of the heated blank from the furnace, down to 400° C., of at least 30° C./s.

Abstract: The invention relates to a process for making a hot stamped coated steel sheet product, comprising the steps of pre-coating a steel strip or sheet with aluminium-or aluminium alloy, cutting said pre-coated steel strip or sheet to obtain a pre-coated steel blank, heating the blank in a furnace preheated to a temperature and during a time defined by diagram according to thickness, at a heating rate Vc between 20 and 700° C. comprised between 4 and 12° C./s and at a heating rate Vc? between 500 and 700° C. comprised between 1.5 and 6° C./s, to obtain a heated blank; then transferring said heated blank to a die, hot stamping the heated blank in the die obtain a hot stamped steel sheet product, cooling at a mean rate Vr between the exit of the heated blank from the furnace, down to 400° C., of at least 30° C./s.

Abstract: The invention relates to a process for manufacturing a corrosion-resistant cold-rolled sheet of iron-carbon-manganese austenitic steel, comprising the following steps: a sheet whose chemical composition comprises, the contents being expressed by weight: 0.35%?C?1.05%, 16%?Mn?24%, the balance of the composition consisting of iron and inevitable impurities resulting from its smelting, is provided; said sheet is cold-rolled; and a recrystallization annealing treatment is carried out on said sheet in a furnace containing a gas chosen from gases that are reducing with respect to iron, the parameters of said annealing being chosen in such a way that said sheet is covered on both its sides with an essentially amorphous (Fe,Mn)O oxide sublayer and with an external crystalline manganese oxide (MnO) layer, the total thickness of these two layers being equal to or greater than 0.5 microns.

Abstract: Coated steel having a well defined and uniform thickness is useful and advantageous for preparing products by hot stamping. Products prepared by hot stamping such a steel are particularly advantageous when subjected to a subsequent spot welding step.

Abstract: The invention relates to a process for making a hot stamped coated steel sheet product, comprising the steps of pre-coating a steel strip or sheet with aluminium—or aluminium alloy, cutting said pre-coated steel strip or sheet to obtain a pre-coated steel blank, heating the blank in a furnace preheated to a temperature and during a time defined by diagram according to thickness, at a heating rate VC between 20 and 700° C. comprised between 4 and 12° C./s and at a heating rate VC? between 500 and 700° C. comprised between 1.5 and 6° C./s, to obtain a heated blank; then transferring said heated blank to a die, hot stamping the heated blank in the die obtain a hot stamped steel sheet product, cooling at a mean rate Vr between the exit of the heated blank from the furnace, down to 400° C., of at least 30° C./s.

Abstract: The invention relates to a hot-rolled steel sheet having a tensile strength greater than 800 MPa and an elongation at break greater than 10%, the composition of which comprises, the contents being expressed by weight: 0.050%?C?0.090%, 1%?Mn?2%, 0.015%?Al?0.050%, 0.1%?Si?0.3%, 0.10%?Mo?0.40%, S?0.010%, P?0.025%, 0.003%?N?0.009%, 0.12%?V?0.22%, Ti?0.005%, Nb?0.020% and, optionally, Cr?0.45%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting, the microstructure of the sheet or the part comprising, as a surface fraction, at least 80% upper bainite, the possible complement consisting of lower bainite, martensite and residual austenite, the sum of the martensite and residual austenite contents being less than 5%.

Abstract: The subject of the invention is a method for the hot-dip coating, in a liquid bath based on zinc containing aluminum, of a running strip of iron-carbon-manganese austenitic steel, in which said strip is subjected to a heat treatment in a furnace in which an atmosphere that is reducing with respect to iron prevails, in order to obtain a strip covered with a thin manganese oxide layer, and then the strip covered with the thin manganese oxide layer is made to run through said bath, the aluminum content in the bath being adjusted to a value at least equal to the content needed for the aluminum to completely reduce the manganese oxide layer, so as to form, on the surface of the strip, a coating comprising an iron-manganese-zinc alloy layer and a zinc surface layer.

Abstract: The subject of the invention is a method for the hot-dip coating, in a liquid bath based on zinc containing aluminum, of a running strip of iron-carbon-manganese austenitic steel, in which said strip is subjected to a heat treatment in a furnace in which an atmosphere that is reducing with respect to iron prevails, in order to obtain a strip covered with a thin manganese oxide layer, and then the strip covered with the thin manganese oxide layer is made to run through said bath, the aluminum content in the bath being adjusted to a value at least equal to the content needed for the aluminum to completely reduce the manganese oxide layer, so as to form, on the surface of the strip, a coating comprising an iron-manganese-zinc alloy layer and a zinc surface layer.

Abstract: The invention relates to a process for manufacturing a corrosion-resistant cold-rolled sheet of iron-carbon-manganese austenitic steel, comprising the following steps: a sheet whose chemical composition comprises, the contents being expressed by weight: 0.35%?C?1.05%, 16%?Mn?24%, the balance of the composition consisting of iron and inevitable impurities resulting from its smelting, is provided; said sheet is cold-rolled; and a recrystallization annealing treatment is carried out on said sheet in a furnace containing a gas chosen from gases that are reducing with respect to iron, the parameters of said annealing being chosen in such a way that said sheet is covered on both its sides with an essentially amorphous (Fe,Mn)O oxide sublayer and with an external crystalline manganese oxide (MnO) layer, the total thickness of these two layers being equal to or greater than 0.5 microns.