SPOT WELDED JOINT USING HIGH STRENGTH AND HIGH FORMING AND PRODUCTION METHOD THEREOF Russian patent published in 2018 - IPC C22C38/02 B23K11/11 B23K11/16 C21D8/02 C21D8/04 C21D9/46 C22C38/04 

FIELD: automotive industry.

SUBSTANCE: present invention relates to a spot welded joint, the assembly of two steel sheets, a method for manufacturing a spot weld, a car body part and a car body. Spot weld consists of two steel sheets, wherein at least one of the steel sheets has 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 %. Chemical composition of the base metal includes 0.05 ≤ C ≤ 0.21 %, 4.0 ≤ Mn ≤ 7.0 %, 0.5 ≤ Al ≤ 3.5 %, Si ≤ 2.0 %, Ti ≤ 0.2 %, B ≤ 0.2 %, Nb ≤ 0.2 %, P ≤ 0.025 %, B ≤ 0.0035 %. Spot welded joint contains a molten zone microstructure containing more than 0.5 % Al and containing a surface fraction of segregated areas lower than 1 %. Said segregated areas are zones larger than 20 mcm² and contain more than the steel nominal phosphorus content.

EFFECT: invention for spot welding is disclosed.

26 cl, 22 dwg, 5 tbl