Abstract: 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 ?m2 and containing more than the steel nominal phosphorus content.

Abstract: Micromechanical component, particularly a timepiece wheel, particularly an escapement wheel, including a substrate with a first material including at least nickel and phosphorus, which substrate is covered, on at least one surface of the substrate of the wheel, by a coating of a second material including at least nickel and poorer in phosphorus than the first material, or devoid of phosphorus, and the second material constitutes the peripheral layer of the wheel at this at least one surface of the substrate.

Abstract: A method for manufacturing a timepiece wheel, according to which a substrate is produced with a first material including at least nickel and phosphorus, the substrate is shaped to the geometry of the wheel, and a coating of the substrate is performed, galvanically and/or chemically, on at least one surface of the substrate of the wheel, with at least one second material, which constitutes the peripheral layer of the wheel at the at least one surface of the substrate of the wheel, and which includes at least nickel and which is poorer in phosphorus than the first material, or which includes nickel and is devoid of phosphorus.

Abstract: 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 ?m2 and containing more than the steel nominal phosphorus content.

Abstract: 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 ?m2 and containing more than the steel nominal phosphorus content.

Abstract: 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 ?m2 and containing more than the steel nominal phosphorus content.

Abstract: The present invention provides a spot welded joint of at least two steel sheets. 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 ?m2 and containing more than the steel nominal phosphorus content.