RU2320440C1 - Method for shaping hollow parts with beveled branch pipes - Google Patents

Abstract

FIELD: plastic working of metals, namely manufacture of parts with beveled branches of hollow blanks.

SUBSTANCE: method comprises steps of flattening tube blank for imparting to it ellipse-like cross section whose small axis is equal to diameter of ready part; then forming on ends of flattened blank beveled portions parallel to generatrix of cylindrical surface of shaped beveled branch; shaping tube blank due to acting upon its lateral surface in direction parallel to said beveled portions.

EFFECT: enlarged manufacturing possibilities, improved quality of ready parts.

5 dwg, 1 ex

Description

The invention relates to the processing of metals by pressure, and in particular to methods of forming hollow parts from tube blanks with oblique elbows.

A known method of forming tees (Guiding technical material RTM 1.4.1999-90 "Production of a welded high-resource pipeline." - M .: NIAT. 1992. - S.104-105, analogue), in which for forming in the dies of finished products with minimal change the wall thickness is fed into the deformation zone the material of the tube billet in the volume corresponding to the volume of the formed branch of the tee, and all the feed material is concentrated in the bevels made in the end parts of the tube billet. Using the known method, thin-walled equal bore tees with one tap are manufactured.

The disadvantage of this method is the impossibility of obtaining high-quality especially thin-walled oblique tees due to breaks in the material on finished products, which are the result of excessive friction forces of the metal on the matrix wall when it moves from the ends of the workpiece through an extensive transition zone to the branch.

A device is known for hydraulic stamping of hollow parts with bends (description of the invention for autoswitch. SU No. 489548, IPC VC 37/29 from 04.24.74, published in bulletin No. 40 from 10.30.75, author Bogoyavlensky K .N., Seryakov E.I., Kobyshev A.N.), a prototype that describes a method for forming hollow parts with oblique elbows, including molding a tube stock by force acting on its side surface to obtain an oblique elbow with a cylindrical surface. In the known method, the metal in the bend is fed both by axial punches from the end parts of the tube stock along curved paths, and by forming inserts performing lateral plastic deformation of the lateral surface of the tube stock bends at the last forming stage. In this way, it is impossible to obtain oblique tees from thin-walled pipe billets, since the reshaping of the bends with an effect on their lateral surface is accompanied by a loss of stability of the material in the form of the formation of longitudinal corrugations along the bend.

Effect: expanding technological capabilities and improving the quality of the processed pipe billets by giving additional direction to the flow of material into the cavity of the oblique tap of the pipe billet.

The technical result is achieved due to the fact that in the known method of forming hollow parts with oblique elbows, including forming a tube stock by force acting on its side surface to obtain an oblique outlet with a cylindrical surface, prior to forming the oblique outlet, the tube stock is flattened to give it an elliptical transverse section, the smaller axis of which is equal to the diameter of the finished hollow part, after flattening at the ends of the pipe billet t bevels extending parallel to the generatrix of the cylindrical surface of the forming oblique discharge, and a force on the lateral surface of the tubular blank is performed in a direction parallel to said bevel.

The flattening of the tubular billet to give it an elliptical cross-section immediately before the operation of forming an oblique elbow facilitates the concentration of the excess volume of material in the zone of intense plastic forming. Therefore, there is no need to move the material from the peripheral sections of the pipe billet to the center of plastic deformation in the process of stamping hollow parts. When forming oblique tees, the major axis of the elliptical cross-section of the tube stock is oriented toward the cavity of the stamped elbow. Therefore, as a result of subsequent force action on the side surface of the tube billet, the material moves to the tee outlet along the shortest path with the smallest bend, and the ellipsoidal cross section becomes round with a diameter at the finished part equal to the smaller axis of the ellipsoid cross section of the tube billet.

The design at the ends of the pipe billet bevels contributes to the force acting on its lateral surface of the directivity of the flow of material into the zone of intense plastic forming. Moreover, an additional orientation to the flow of material is given by forces acting parallel to the obtained bevels. Thus, the bevel performs the function of a rigid supporting element located in the region of elastic deformations and helps to straighten (optimize) the trajectories of the plastic flow.

Due to this, using the proposed method not only improves the quality of known hollow parts, but also bends are stamped with a smaller radius of the transition zone and a smaller angle of inclination of the branch to the longitudinal axis of the workpiece, i.e. expanding technological capabilities by increasing the resource of plasticity of the material of the tee.

Figure 1 shows the flattening of the tube stock before shaping to give it an elliptical cross-section.

Figure 2 - diagram of the formation of bevels at the ends of the pipe billet.

Figure 3 - diagram of the force on the side surface of the pipe billet in the direction parallel to the bevels.

Figure 4 is a diagram of the formation of an oblique tap.

Figure 5 is a section along "aa", figure 4.

The method of forming hollow parts with oblique elbows 1 includes flattening the tube stock 2 to give it an elliptical cross-section 3, the smaller axis 4 of which is equal to the diameter D of the finished part 5; the design of the bevels 6 at the ends 7 of the tube stock 2 parallel to the generatrices of the cylindrical surface 8 of the formed oblique outlet 1; forming in the stream 9 of the stamp 10 by force on the side surface 11 of the pipe billet 2 in a direction parallel to the bevels 6.

An example of the method

Finished part 5 (equal bore oblique tee) with a diameter of D = 21 mm with a wall thickness of 0.5 mm and a height of the oblique bend is formed from a tube 2 with an outer diameter of 25 mm with a wall thickness of 0.5 mm and a length of 40 mm from corrosion-resistant steel 12X18H10T 1, equal to 10 mm, inclined to the longitudinal axis of the tube billet 2 by an angle α = 50 °. To do this, in a special device (not shown in the drawing) installed on the PYE-250 press, the tube billet 2 was flattened with a diameter of 25 mm to give it an elliptical cross-section 3, whose smaller axis 4 is 21 mm. At the ends 7 of the tube billet 2, bevels 6 were formed with an angle of inclination to its longitudinal axis α = 50 °. The tube billet 2 with bevels 6 was filled with Wood's alloy and, after hardening, was installed in stream 9 of stamp 10 so that the bevels 6 were parallel to the generatrix of the cylindrical surface 8 of the formed oblique elbow 1. The finished part 5 was formed into an oblique tee by applying force P = 145 kN on the side surface 11 of the tube stock 2 in a direction parallel to the bevels 6. The stamped equal bore oblique tee had a circular cross-sectional shape. The maximum thickening of the material in the area opposite to branch 1 was 8%, and there was no thinning at the top of branch 1. Thus, the equal bore oblique tee had the minimum thickness for parts of this class, the height of the branch, sufficient for the subsequent use of automatic welding, which indicates its high quality and the expansion of technological capabilities for producing such hollow parts.

Claims (1)

A method of forming hollow parts with oblique elbows, including forming a tube stock by force acting on its side surface to obtain an oblique outlet with a cylindrical surface, characterized in that the tube stock is flattened to give it an elliptical cross-section, the smaller axis of which is equal to the diameter of the finished hollow part , after flattening at the ends of the tube billet, bevels are arranged parallel to the mold forming a cylindrical surface of oblique discharge, and a force on the lateral surface of the tubular blank is performed in a direction parallel to said bevel.

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