SU839628A1 - Tool for tube cold rolling - Google Patents

Description

The invention relates to the processing of metals by pressure and can be used in pilcher cold rolling of pipes. A technological tool for piligrim cold rolling of tubes is known, consisting of a mandrel and rolls with zones of reduction, reduction and calibration, while forming a ridge and mandrel in a reduction zone is outlined by convex bends, and in a reduction zone forming a ridge - a linear cone, mandrel moline l. The disadvantage of this tool is that during the rolling process, increased contact stresses are created on the straight section of the mandrel (due to the linear-cone ridge profile), as a result of which it is difficult to move the pipe along the mandrel during deformation and the reloading of the pipe is complicated. often resulting in defect formation on the inner surface of the pipe. In a pinch, where the pipe is usually already formed, and the metal is sufficiently hardened, these hyperbolic profiles lead to excessive compression and normal contact voltages / resulting in sticking of the metal to the tool, the quality of the pipe surface deteriorates and other technological indicators. A technological tool for cold piligrim tube rolling is also known, including rolls with a variable cross-section stream having a calibrating zone, adjacent to it a crimping zone with a parabolic tongue, convex facing outward, a reduction zone with a parabolic bulge facing, outward, ridge profile and mandrel parabolic concave forming in the area corresponding to the roll section of the crimp zone 2. The disadvantage of this tool is that by increasing the overall level of unevenness in the ratio of deformation along the wall and the pipe diameter in the crimping zone, conditions of increased deformations in diameter are created without the wall being crimped and for a number of cases of particularly ductile pipes with a thick one. longitudinal cracks and folds appear on the inner surface of the pipes in the zone of reduction.

The purpose of the invention is to improve the quality of the inner surface of low-plastic pipes with a thick wall.

The goal is achieved by the fact that a tool for cold rolling of tubes containing rolls with a brook of variable cross section having a calibrating zone, an adjacent section of a crimping zone with a parabolic ridge facing outwards, a reducing zone with outwardly parabolic, facing outwards, a ridge profile, and a mandrel with a parabolic concave formation in the area corresponding to the part of the roll of the crimping zone with a parabolic ridge, a creek a stream at the beginning of the compression zone is formed of a concave parabolo and the corresponding section of the generator of the mandrel is a convex parabola and is connected to the section corresponding to the roll reduction zone by a cylindrical shape.

The drawing shows the sweep pattern of the deformation zone with the use of the proposed tool.

The tool for cold rolling of tubes includes rolls 1 and mandrel 2. Rolls are made with a stream of variable (decreasing) cross section and having a reducing length 3 with a parabolic, reversed outward bulge, a ridge profile, calibrating zone 4 with a cylindrical ridge profile and a crimping area.

The crimping area is composed of a starting section 5, the crest of which is formed by a concave parabola and an area 6 adjacent to the calibrating area with a parabolic crest facing convex outward.

The mandrel is made up along the length of the sections corresponding to the roll zones, which form a stream in its zones of reduction and calibration, which are similar to the profile and crest, and have a cylindrical shape in the section corresponding to the roll reduction zone. The forming mandrel is composed of a parabolic concave section at a length corresponding to the roll section of the swathing area of the roll, a parabolic roll that is convex at the length of section 3, a cylindrical section corresponding to the reducing roll area 3, and a cidandric section corresponding to the calibrating area of the roll 4.

The technological tool during operation provides in the reduction zone 3 a reduction of the workpiece 7 across the diameter of a variable nature so that at the beginning of the zone the intensity of reductions is maximum and by the time the inner surface of the pipe meets the cylindrical part of the mandrel 2 (at the end of the reduction zone; - minimal.

On the convex portion 5 of the roll, compression begins in the diameter and wall thickness of the pipe with a gradual increase in the deformations and a subsequent decrease in the length of the section 6 of the crimping zone in which the main part of the deformation of the pipe’s cross section occurs. In Kshibischa zone 4 finishes pipe in diameter and wall thickness.

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The proposed roll stream profile allows a reduction in the net reduction zone. In this case, the higher the degree of the parabola, the smaller the number of cycles in the zone of pure reduction (without compression on the wall).

The proposed profile of the technological tool can be effective when rolling pipes from any steel and alloys, under various thermal conditions and technological lubricants, but it can be especially effective with significant deformations in diameter, when rolling pipes from low-plastic materials, as well as thick-walled pipes. The proposed tool provides an improvement in the quality of the pipes by reducing defects of the type of gray hair on the inner surface, improving the accuracy of the geometric dimensions, including reducing the small-period curvature.

Claims (2)

Invention Formula A tool for cold rolling of tubes containing rolls with a variable cross-section stream having a calibrating zone, an adjacent section of the crimping zone with a parabolic ridge, convexity facing outwards, a reducing zone with a parabolic, turned convexity outwardly with a ridge profile, and a mandrel with a parabolic concave forming a section corresponding to a roll section of a crimping zone with a parabolic ridge, characterized in that, in order to improve the quality of the inner surface of low-plastic pipes with thick At the beginning of the zone, the crest of the stream formed by a concave parabola, and the corresponding section of the forming mandrel is a convex parabola and is connected to the section corresponding to the roll reduction zone, which is cylindrical. Sources of information taken into account in the examination 1, USSR Author's Certificate 255893, CL. B 21 B 21/00, 1967. 2. The patent of Germany 1777043, CL. 7a, 21-02, 1968.