A spot welded joint of at least two steel sheets is provided. At least one of the steel sheets presents yield strength above or equal to 600 MPa, an ultimate tensile strength above or equal to 1000 MPa, uniform elongation above or equal to 15%. The base metal chemical composition includes 0.05≤C≤0.21%, 4.0≤Mn≤7.0%, 0.5≤Al≤3.5%, Si≤2.0%, Ti≤0.2%, V≤0.2%, Nb≤0.2%, P≤0.025%, B≤0.0035%, and the spot welded joint contains a molten zone microstructure containing more than 0.5% of Al and containing a surface fraction of segregated areas lower than 1%, said segregated areas being zones larger than 20 μm.sup.2 and containing more than the steel nominal phosphorus content.

A spot welded joint of at least two steel sheets is provided. At least one of the steel sheets presents yield strength above or equal to 600 MPa, an ultimate tensile strength above or equal to 1000 MPa, uniform elongation above or equal to 15%. The base metal chemical composition includes 0.05≤C≤0.21%, 4.0≤Mn≤7.0%, 0.5≤Al≤3.5%, Si≤2.0%, Ti≤0.2%, V≤0.2%, Nb≤0.2%, P≤0.025%, B≤0.0035%, and the spot welded joint contains a molten zone microstructure containing more than 0.5% of Al and containing a surface fraction of segregated areas lower than 1%, said segregated areas being zones larger than 20 μm.sup.2 and containing more than the steel nominal phosphorus content.

The present invention concerns the field of vehicle technology and industrial-plant technology and relates to a brake disc provided with protection from wear and corrosion and to a method for production thereof. The known solutions have the disadvantage that the coating for providing protection from corrosion and wear is applied to the frictional surfaces of the brake disc and is rubbed off straight away during the first braking operations. The present invention addresses the problem of providing a brake disc that has improved and durable protection from corrosion and wear. The significantly improved properties of the brake disc in terms of protection from corrosion and wear are achieved according to the invention by at least the region of the frictional surfaces (2) having an AlSi-based diffusion layer (3), which has a layer thickness of 0.1 mm to 0.6 mm and is formed in the process of interaction with the steel or grey cast iron of the metal main body (1). The brake disc according to the invention can be used for example in vehicles or as a braking system for industrial brakes or in wind turbines.

A process of forming an erosion, oxidation, and wear resistant shot chamber, either a gooseneck or a shot sleeve, is provided. The process utilizes a self-healing erosive wear resistant coating on a liner of refractory metal to serve as the working surfaces of a shot chamber. Such a shot chamber is expected to have an improved service life for die casting of corrosive metals and alloys, including hot chamber die casting of aluminum alloys. An improved hot dipping process using stirring in the molten metal bath is also disclosed.

A process of forming an erosion, oxidation, and wear resistant shot chamber, either a gooseneck or a shot sleeve, is provided. The process utilizes a self-healing erosive wear resistant coating on a liner of refractory metal to serve as the working surfaces of a shot chamber. Such a shot chamber is expected to have an improved service life for die casting of corrosive metals and alloys, including hot chamber die casting of aluminum alloys. An improved hot dipping process using stirring in the molten metal bath is also disclosed.

The present disclosure provides a hot-press formed part comprising a plated steel sheet and an aluminum alloy plated layer formed on the plated steel sheet, wherein the aluminum alloy plated layer comprises: an alloying layer (I) formed on the plated steel sheet and containing, by weight %, 5-30% of Al; an alloying layer (II) formed on the alloying layer (I) and containing, by weight %, 30 to 60% of Al; an alloying layer (III) formed on the alloying layer (II) and containing, by weight %, 20-50% of Al and 5-20% of Si; and an alloying layer (IV) formed continuously or discontinuously on at least a part of the surface of the alloying layer (III), and containing 30-60% of Al, wherein the rate of the alloying layer (III) exposed on the outermost surface of the aluminum alloy plated layer is 10% or more.

The present disclosure provides a hot-press formed part comprising a plated steel sheet and an aluminum alloy plated layer formed on the plated steel sheet, wherein the aluminum alloy plated layer comprises: an alloying layer (I) formed on the plated steel sheet and containing, by weight %, 5-30% of Al; an alloying layer (II) formed on the alloying layer (I) and containing, by weight %, 30 to 60% of Al; an alloying layer (III) formed on the alloying layer (II) and containing, by weight %, 20-50% of Al and 5-20% of Si; and an alloying layer (IV) formed continuously or discontinuously on at least a part of the surface of the alloying layer (III), and containing 30-60% of Al, wherein the rate of the alloying layer (III) exposed on the outermost surface of the aluminum alloy plated layer is 10% or more.

The present invention relates to a hot stamped component, a precoated steel sheet used for hot stamping, and a hot stamping process. The hot stamped component of the present invention is provided with a coating of aluminium or an aluminium alloy on at least one surface of the base steel, the coating is produced by interdiffusion between the base steel and a precoating of aluminium or aluminium alloy, and the coating has a thickness of 6 to 26 μm.

A pre-coated steel sheet wherein at least a region at the periphery (7) of at least one (6a,6b) of the opposite faces (6a,6b) of said pre-coated sheet (1,1′) is coated with an additional coating (8) selected for increasing the vapor pressure between the pre-coating (2) and said additional coating (8) during a laser welding method up to a critical pressure at which the pre-coating (2) is ejected away from the weld (14). Preferably, the vaporization temperature of the additional coating (8) is greater than the vaporization temperature of the pre-coating (2) and the additional coating includes gammagene elements like carbon and/or nickel. A steel part obtained by laser welding, preferably butt laser welding, of at least a first and second pre-coated steel sheet (1,1′) as above indicated is also provided.

A pre-coated steel sheet wherein at least a region at the periphery (7) of at least one (6a,6b) of the opposite faces (6a,6b) of said pre-coated sheet (1,1′) is coated with an additional coating (8) selected for increasing the vapor pressure between the pre-coating (2) and said additional coating (8) during a laser welding method up to a critical pressure at which the pre-coating (2) is ejected away from the weld (14). Preferably, the vaporization temperature of the additional coating (8) is greater than the vaporization temperature of the pre-coating (2) and the additional coating includes gammagene elements like carbon and/or nickel. A steel part obtained by laser welding, preferably butt laser welding, of at least a first and second pre-coated steel sheet (1,1′) as above indicated is also provided.