METHOD FOR PRODUCING HOLLOW METAL SHUT-OFF ELEMENTS FOR BALL VALVES Russian patent published in 2021 - IPC B21D51/08 

FIELD: metals processing.

SUBSTANCE: invention relates to the processing of metals by pressure and can be used in the manufacture of hollow spherical plugs of shut-off valves with a through central hole made of corrosion-resistant materials. An outer pipe blank and an inner pipe are installed in a die containing two matrices with a hemispherical working surface and a mandrel. Their coaxial position is ensured by means of four guide rods. Preliminarily, the pipe billet and the inner pipe are turned to obtain an inner chamfer with an angle of 45° on the pipe billet, and an outer chamfer with an angle of 45° on the inner pipe. Deformation is performed by crimping the pipe billet with the formation of a spherical shell from it and with obtaining an interference fit between the abutting edges of the spherical shell and the inner pipe.

EFFECT: quality of the resulting product is increased due to ensuring strict alignment of the spherical shell and the branch pipe with a reliable joint density, which excludes their rotation.

2 cl, 3 dwg, 1 ex