SCREW FITTING METHOD Russian patent published in 2022 - IPC B21B19/04 B21B37/56 

FIELD: screw-piercing method.

SUBSTANCE: invention relates to a screw-piercing method. The heated workpiece is fed into the working rolls, the workpiece is captured by the rotating rolls and the workpiece is pierced with a mandrel into the sleeve. After the billet is pierced into the sleeve, the sleeve is additionally pierced to obtain a pipe. Capturing the blank during its piercing is carried out with a degree of deformation per half-turn of 0.4-1.5%, and piercing is carried out with a decrease in the outer diameter of the sleeve by 10-25% compared to the diameter of the blank. The sleeve is gripped by rolls during its piercing, which is performed with a degree of deformation of 0.6-3% per half-turn and is carried out with an increase in the pipe diameter in relation to the sleeve diameter by 3-25%.

EFFECT: quality of the outer and inner surface of the sleeve is improved with the development of the structure.

1 cl, 2 dwg, 1 ex