SU1222352A1 - Horn-shape core - Google Patents

Description

The invention relates to mechanical engineering, in particular, to the design of a tool for bending pipes with simultaneous dispensing, namely to horn-like cores for the production of bends from tubular blanks.

The purpose of the invention is to improve the quality of products, i.e., to create a horn-like core with equal strength along its length while further reducing its mass.

Fig, 1 shows a horn-like core, open, its form; in fig. 2 is a section A-A in FIG. one; in fig. 3 is a section BB in FIG. one.

Corn-shaped core contains a guide 1, forming 2 and calibrating 3 areas. On the border of the transition of the guide section 1 to the forming 2, a continuous section zone 4 is located symmetrically with respect to the said border. The remaining forming section and the entire calibrating 3 are made with an internal cavity 5.

In order to have the same voltage in any section of the forming section of the core equal to the voltage in the dangerous section, it is necessary to reduce the cross-sectional area of this section from its beginning to the end. Studies of the stress state of the core with a cavity, starting from the beginning of the forming section of the core, show that to create an equal-strength horn, it is necessary that

the cross section was continuous, and the wall thickness of the forming section evenly decreased from –y at the beginning of the section to zero at its end. From design considerations and from the experience of casting hollow blanks, the wall thickness of the sizing section is assumed to be do / 8. Consequently, it is found that for an equally strong, horn-like core, it is necessary to have a continuous initial section and an equal strength

a wall whose thickness is uniformly reduced from do / 2 at the beginning of the section to do / 8 at its end. From the technological conditions of the casting process, as well as to create a safety margin for the dangerous section, in the transition zone of the forming section to the guide there should be a continuous section area not less than the diameter of the section of the guide section symmetrically relative to the boundary.

Compared to the known core, the equal-strength, cornhorn core 10 allows thick-walled carbon steel taps with relative wall thickness, I and stainless and alloyed steels to be pulled. At the same time, when drawing branches with a relative wall thickness of S / DH 0.1, the life of the core offered is significantly increased compared with the known 2-10 times, depending on the conditions of drawing and the material of the pipe (workpiece). All this entails the expansion of the technological capabilities of an equal strength horn-shaped core.

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fig.Z

Claims (2)

HORN-shaped CORE for manufacturing bends, having successively arranged guide, forming and calibrating sections with an internal hole, the wall thickness of the forming section being uniformly reduced in the direction of the calibrating section, characterized in that, in order to improve the quality of the products and reduce the metal consumption, it is provided with a continuous section sections located between the guide and the forming sections, the wall thickness of the calibrating section is constant and equal to the wall thickness of the mold the stripping portion at the boundary of its transition to the calibrating one, and the wall thickness of the shaping portion S is determined by the formula do ι ___ 3do__ 2 '8 (d ₀ —D) do) where d is the diameter of the cross section of the forming section; do — diameter of the section guide _{on the} plot; D is the diameter of the cross section of the calibrating section. SU „„ 1222352 FIG. 1