Abstract: A method for producing a part includes providing a first and a second precoated sheet (1,2), butt welding the first and second precoated sheets (1) to obtain a blank (15), and heating the blank (15) to a heat treatment temperature at least 10° C. lower than the full austenitization temperature of the weld joint (22) and at least 15° C. higher than a minimum temperature Tmin: T min ? ( ° ? ? C . ) = AC ? ? 3 ? ( WJ ) - ? IC max 100 ? ( Ac ? ? 3 ? ( WJ ) - 673 - 40 × Al ) .

Abstract: A method to improve the formability of steel blanks, for steels containing at least 5% martensite, and possibly some ferrite, bainite and residual austenite and having an ultimate tensile strength of at least 500 MPa and possibly having a metallic coating layer on at least one side, wherein the steel blank is heat-treated on at least part of its peripheral thickness using at least one heat source, which heats the steel in a heat-treated zone to a temperature between 400° C. and 1500° C. without melting the steel in any points of the heat-treated zone.

Abstract: A method for producing a part includes providing a first and a second precoated sheet (1,2), butt welding the first and second precoated sheets (1) to obtain a blank (15), and heating the blank (15) to a heat treatment temperature at least 10° C. lower than the full austenitization temperature of the weld joint (22) and at least 15° C. higher than a minimum temperature T T min ? ( ° ? ? C . ) = AC ? ? 3 ? ( WJ ) - ? IC max 100 ? ( Ac ? ? 3 ? ( WJ ) - 673 - 40 × Al ) .