SU854537A1 - Tool for expanding hollow works - Google Patents

Description

(54) TOOL FOR DISTRIBUTING HOLLOWS

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This invention relates to the hot working of metals by pressure, in particular, to tools for the preparation of large-sized seamless pipes.

A known tool for dispensing hollow blanks, a tip with a working part, made in the form of a radius mating of the side surface with the tool face.

The deformation of the metal during the distribution of the workpiece with such a tool occurs within the deformation zone both to the sides and under the tool tip.

Since the distribution of a thick or colder wall requires greater force than deformation of a thinner or hotter wall that is more pliable, first of all, the thin or warmer wall is deformed, which increases the stiffness. In this case, the lateral displacement of the tip is not restrained by anything.

Also known is a tool that contains a tip with working and lead-in sections, made in the form of a centering, protrusion concentric with the working section 2.

However, the lead-in portion of this tool is for guidance only. To prevent lateral displacement during dispensing, it is required to produce uniform heating and good centering of the workpiece in the container, as well as careful centering of the holders and the piercing tool relative to the container.

10 in the absence of specialized equipment and with a half-closed or open dispensing with this tool, the wall thickness increases, since in the absence of hard backing of the container in the container and the hard direction of the piercing tool, the lead-in part may prevent its lateral displacement towards the more pliable wall.

20

The purpose of the invention is to improve the quality of the workpieces by reducing the lateral displacement of the tip. This goal is achieved by the fact that in the tool for dispensing hollow

25 blanks containing the tip with the working and lead-in parts, the lead-in part of the tip is made with a section protruding beyond the limits of the deformation zone by an amount proportional to

Claims (2)

30 of the original delimitation, but in general. the length of the lead-in part is defined by the relation LUN-- - m, 1 where L is the length of the lead-in part; h - the height of the deformation zone during distribution; S is the maximum wall thickness; Sf - wall thickness is minimal; m is the length of the working part. The technical solution is shown in the drawing, on. which is shown at the moment of distribution of the workpiece, the tip 1 with the working section 2 of length m and behind, the walking part 3, length L, extending beyond the limits of focusing h by the value of Е L + m-h. This overhang is an obstacle to lateral movement of the tip. In the plane of maximum differentiation, a tensile force P g h S acts on the thick wall, where Ce is the yield strength of the workpiece material at deformation temperature S is the thickness of the thick wall; a force P h S, acts on a thin wall within the deformation zone, where Sjj is the thickness of the thin wall; beyond the deformation zone in section B, a force P 3 IS g acts where 0 is tensile stress in the wall. From the condition of the workpiece equilibrium, it follows that 1 i ъ 0 To prevent deformation of the thin wall outside the deformation zone in section E, the stress it should be less than the yield stress Ted - cSc, whence P L. 3y. In Sa, consequently, tfg Е S.1 d h S - 6g4 h Sg from where E h. The total length of the lead-in part L is determined from the formula L b + h-m, whence L 7 h + + h - m, i.e. L h -t- - m. The length of the tool part determined by the derived formula for dispensing extends beyond the deformation zone and completely eliminates the increase in the initial difference in thickness and the flow of metal under the tip during dispensing. Example. For the free distribution of the hollow billet with the initial internal diameter d 500 mm to the diameter d 640 mm, the distribution tool is provided with a tip made with the following parameters. The length of the working section m is equal to the height of the deformation zone h, the value of which lies in the range (0.5-1.0) u-j - then m h (0.5-1.0) 640-500. 35-70 mm. From the experimental data, the ratio of the maximum wall thickness to the minimum in the original blanks is in the range f (1.5-3), the protruding lane of the lead-in part is determined by e h (), i.e. B7 (35-70) - (1.5 -3) l, whence E 20-140 mm. If the maximum value of E is 140 mm, then the entire length of the lead-in part when m is b b-2. + B- | -n | 4o + o - 1Amm The use of the tool allows to reduce the varicosity of pipes obtained from hollow billets with the use of distribution and the laboriousness of their subsequent machining, as well as to reduce the waste metal consumption by eliminating metal leakage under the tip. The invention The tool for dispensing hollow blanks, containing a tip with working and lead-in chucks, is due to the fact that, in order to improve the quality of the blanks by reducing the lateral displacement of the tip, the lead-in portion of the tip is made with a portion protruding beyond the hearth limits deformations by an amount proportional to the initial difference wall thickness, and the total length of the lead-in part is determined by the relation (,,) - m, where L is the length of the lead-in part, h is the height of the deformation zone in the workpiece; -1, respectively, the maximum and minimum wall thickness of the workpiece; m is the length of the working part. Sources of information taken into account in the examination 1. F. Danilov. et al. Hot rolling and pressing tubes. Metallurgists, 1972, p. 561, fig. 188. 2.Prozorov L.V. Pressing of steel and refractory alloys, Mashinostroenie, 1969, p. 117-119, ris.71,72.