PASS SEQUENCE OF TUBE-MOULDING MILL Russian patent published in 2009 - IPC B21C37/06 B21D7/08 

FIELD: metallurgy.

SUBSTANCE: pass sequence contains matches of gauged horizontal rollers and dead vertical rollers, installed after each forming cage, and includes three two-high and one four-roll gauge. Stock tubes allows outer diametre D. Holes in rollers of the first gauge are implemented by circles of radius R₁=(0.495…0.50)·D. In the second and the third gauges holes are implemented as trapeziform, with lateral minor surfaces of the same radiuses, with major surface of the second gauge of radius R₂=1.6·D and similar surface of the third gauge with R₃=3.2·D. Breakout height of gauges into rollers is appropriately: H₁=(0.44…0.46)·D, H₂=(0.38…0.40)·D and H₃=(0.39…0.41)·D. Vertical rollers behind the first cage allows labor concave with radius r₁=R₁ behind the second cage - with r₂=R₂ and behind the third cage - with r₃=R₃ fourth finishing gage of system can be implemented with ability of dimensions changing by means of rearrangement in overall axial plane three rollers which are components of gauge.

EFFECT: invention provides receiving of thin-walled tube of square cross-section from round stock tube for minimum pass number.

2 cl, 1 ex, 2 dwg