RU2087229C1 - Tool for shaping hollow axially symmetrical articles - Google Patents

Abstract

FIELD: plastic metal working, namely cold forming with use of elastic medium pressure, particularly production of superthin-wall members of pipeline system. SUBSTANCE: tool is placed in tubular blank 9 in such a way that necked parts 8 of metallic sleeves 6 of end portions 5 of tool are arranged on transition portions of blank joined to its part to be expanded; central portion 7 of elastic cylindrical part 4 is arranged on portion of blank to be maximally expanded, and then said blank is placed in impression of die of forming apparatus. Inner pressure of elastic medium is created at axially upsetting blank. Said pressure is distributed differentially along inner surface of blank depending upon expanding degree. EFFECT: possibility of making superthin-wall complex-structure articles with lowered number of rejects. 1 dwg

Description

 The invention relates to the processing of metals by pressure, in particular to cold stamping using the pressure of an elastic medium, and can be used to obtain extra-thin-walled elements of pipeline systems.

 A device for hydraulic stamping of hollow axisymmetric cylindrical parts containing a matrix, axial compression punches and a retaining liner made of elastic material with a cylindrical axial hole for accommodating the deformable part of the workpiece (A.S. USSR N 1348025, B 21 C 37/29, 1987).

 In the known device, due to the elastic insert providing pressure to the outer surface of the deformable part of the workpiece, the workpiece is distributed with an uneven back pressure that is the smallest in the center of the liner and the greatest at the transition point of the workpiece into the part being distributed. This avoids saddling in the center of the part being distributed.

 However, the creation of the highest pressure of the backing of the outer surface of the workpiece at the transition to the distributable part simultaneously complicates the flow of the workpiece material in the process of its axial upsetting and may lead to a loss of stability. This, in particular, does not allow the use of the known device in the manufacture of especially thin-walled products.

 In addition, the uneven back pressure and the geometric parameters of the elastic retaining liner lead to a non-stamping of the product to a given shape.

 A known tool for sheet stamping, containing an elastic cylindrical part and metal bushings (and.with. 845975, B 21 D 22/10, 1979, prototype), designed for the shaping of axisymmetric products.

 The use of metal bushings in a known tool allows you to limit the deformation of the elastic cylindrical part in a given range and get the necessary diagram of movements. As a result, the workpiece takes the desired shape without using a matrix.

 In this case, in the process of deformation of the workpiece at the transition to the distributable part, there is no support of its outer surface and a pressure differential of the elastic medium occurs on the inner surface. This leads to the appearance of additional tensile stresses and, as a consequence, to the loss of stability of the material (thinning, rupture).

 Thus, the known tool design cannot be used in the manufacture of complex axisymmetric products from especially thin-walled blanks.

 The design of the inventive tool allows you to reduce the differential pressure of the elastic medium in the areas of transition of the workpiece into the distributed part. Thus, to expand the range of manufactured products, getting particularly thin-walled, complex configuration of the part with the diameters of the parts being distributed, corresponding to (1.2-1.5) the diameter of the workpiece.

 The specified technical result is achieved by the fact that in the known tool for shaping hollow axisymmetric products containing an elastic cylindrical part and metal bushings, the latter are made tapering, installed on both ends of the elastic cylindrical part, covering it with its wide ends, made with the possibility of distribution during shaping from the side tapering parts, covered in turn by the material of the elastic part.

 In the claimed design of the tool, the execution of the sleeves tapering and with the possibility of distribution during compression of the elastic part allows the component of the generated internal pressure to be spent on the deformation of the tapering parts of the bushings. As a result, the internal pressure on the surface of the workpiece opposite to these parts decreases, and as they are distributed, it gradually increases. Moreover, since at the point of narrowing, the bushings are covered by the elastic material of the cylinder, an effective internal support of the workpiece is simultaneously carried out and the deformation process proceeds stably.

 The drawing shows a tool for forming hollow axisymmetric parts, on the left before forming, on the right at the end.

 The products are formed in a stamping device, which includes a detachable die 1 and axial compression punches 2, 3. The tool contains an elastic cylindrical part 4, the end sections 5 of which are covered by the wide ends of the metal sleeves 6, made tapering to the central section 7 of the elastic part 4. In places narrowing 8 metal bushings 6 are covered by the material of the Central section 7 of the elastic cylindrical part 4.

 In the process of forming products, the tool works as follows.

 The tool is assembled and placed in the inner cavity of the tubular billet 9, placing places of narrowing 8 metal sleeves 6 in the areas of transition of the workpiece into the part being distributed. The workpiece 9 with the tool is installed in the creek of the matrix 1, punches 2, 3 are brought to the ends of the workpiece 9 and the workpiece is axially compressed, creating an internal pressure of the elastic medium of the cylindrical part 4.

 At the end sections 5 of the elastic cylindrical part 4, the pressure of the filler is transmitted to the inner surface of the metal sleeves 6, and the pressure on the corresponding sections of the pipe billet 9 is reduced. Moreover, in areas that are not involved in shaping, the internal pressure is reduced to a minimum. In the sections of the transition of the workpiece into the part being distributed, the internal pressure is partially spent on deforming the tapering sections 8 of the metal sleeves 6 and, as they are distributed, it increases, approaching at the end of the shaping, the internal pressure in the central section 7 of the elastic cylindrical part 4, corresponding to the pressure in the center of the part being distributed.

 Thus, in the process of forming the workpiece along the creek of the matrix, the internal pressure in it is distributed in sections differentially depending on the distribution size.

 This allows, in particular, to reduce the differential pressure of the elastic medium in the areas of the transition of the workpiece into the part being distributed and to avoid loss of stability of the material (rupture, thinning).

 The geometric parameters of the metal bushings are set depending on the geometric dimensions of the workpiece and the formed product.

 For example, when forming a cross-piece with a diameter of 80x80 from a tubular billet of titanium alloy OT4-0 with a length of 150 mm, a diameter of 80 mm and a wall thickness of 0.5 mm, metal bushings are made of AMG-2M alloy with a wall thickness of 1.0 mm 35 mm long with a tapering section length of 12 mm, a maximum diameter of 79 mm and a minimum diameter of 60 mm.

Claims (1)

 A tool for forming hollow axisymmetric products containing an elastic cylindrical part and metal sleeves, characterized in that the metal sleeves are made tapering, are installed at both ends of the elastic cylindrical part, covering it with their wide ends, are made with the possibility of distribution during shaping from the side of the tapering parts covered in turn, the material of the elastic part.