METHOD FOR MANUFACTURE OF WELDED PART OF MOLDED HIGH-STRENGTH STEEL AND PART MADE BY SUCH A METHOD Russian patent published in 2023 - IPC B23K9/23 C21D8/04 C22C38/38 C22C38/54 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to a method for the manufacture of a welded part. The method for the manufacture of a welded part includes production of a hot-rolled steel product of high-strength air-hardened steel with a thickness of material of at least 1.5 mm, while the hot-rolled steel product has the following chemical composition, wt.%: C from 0.03 to 0.4, Mn from 1.0 to 4.0, Si from 0.09 to 2.0, Al from 0.02 to 2.0, P ≤ 0.1, S ≤ 0.1, N from 0.001 to 0.5, Ti from 0.01 to 0.2, Cr from 0.05 to 2.0, B from 0.001 to 0.1, Mo from 0.01 to 1.0, V from 0.01 to 0.2, if necessary, Ni from 0.02 to 1.0, Nb from 0.01 to 0.1, while the rest is iron and related elements, subsequent air hardening of the hot-rolled steel product to obtain a product having the minimum yield strength Rp0.2 of 450 MPa, the minimum tensile strength Rm of 700 MPa, and/or relative elongation A5 of at least 6%, molding of the hot-rolled steel hardened product, and making of welded joints by melting welding to obtain a part. The part has a complex phase microstructure in the area of main material, as well as in the area of thermal impact with a bainite content of more than 50%, preferably of more than 80%, the most preferably of more than 90%.

EFFECT: high capacity for cold stamping in combination with high steel strength or fatigue strength and operational strength with dynamic stress of welded parts.

9 cl, 6 dwg