MANUFACTURING METHOD OF BUSHINGS CROSS-SCREW ROLLING MILL Russian patent published in 2010 - IPC B21B19/04 B21B25/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to metal deformation process and can be used at broaching of bushings at pipe-rolling plants at manufacturing of smooth and profiled hot-rolled pipes and piece part components of different machine-building parts. Method includes broaching, rolling, reducing and calibration of bushings in rolling mill by rolls with sections of broaching, rolling, reducing and calibration of bushings by external surface and piercing mandrel, centred in deformation site by hollow rod. Rollers after bushing reducing implement cobbing of its wall and calibration of bushing by external and internal diametre on rolled parallel plug, which is located between piercing mandrel and rod. Bushing reducing is implemented up to contact of inner surface of bushing to rolling mandrel. Bushing calibration on rolling mandrel is implemented after cobbing of bushing wall and its thinning not less than for 5% and not more than for 15%. Centering of rolling mandrel, and together with it piercing mandrel on rolling axis is implemented by working rollers and calibrated bushing at its passing through deformation site.

EFFECT: invention provides receiving of bushings with thickness variation less than 8%, constancy of diametral dimensions of its external and internal surfaces, including end sections of bushing.

1 dwg