WELDED STRUCTURE AND METHOD FOR PRODUCING LAP WELDING JOINT BY SPOT LASER WELDING Russian patent published in 2021 - IPC B23K26/22 B23K26/244 

FIELD: welding.

SUBSTANCE: invention relates to a method for manufacturing a welded structure and can be used in manufacture of welded metal structures from sheet workpieces for the frames of the sidewall of a subway car. The lap connection of the flange shelf and the sheet is assembled, the flange shelf is pressed against the sheet without a gap, and laser welding is performed on a copper substrate using a welding laser head forming a spot laser weld. The laser beam is moved in a spiral from the outer diameter of the inner circumference to the edge of the welding spot with circular oscillations perpendicular to the trajectory of movement. The welding laser head is positioned perpendicular to the welded item, welded with weld penetration in the flange to the entire thickness and weld penetration in the lower sheet to a predetermined depth in one pass, using a fibre laser. Welding is performed with a smooth increase in the power of the laser beam at the beginning of the welding process from the minimum value to the preset value in a hundredth of a second and with a smooth decrease in the power of the laser beam at the end of the process from the preset value to the minimum value in less than two hundredths of a second. Welding is executed without associated heating.

EFFECT: increase in the productivity of execution of a weld spot for a lap welding joint, reduction in the residual heat deformations in the welded structure, and increase in the precision of the resulting structure.

3 cl, 8 dwg