Method of producing thin-wall shells

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and may be used in producing thin-wall shells from maraging steel. Hollow shaped workpiece is made from bar section by extruding and cutting. Shaped workpiece consists of large and small cylinders jointed by adapter cone and features wall thickness varying in height. Large cylinder wall thickness is twice is lathe as that of adapter cone. That workpiece is subjected to extrusion and thermal treatment for stress relief to make thin-wall shell. Rotary extrusion is carried out in three stages with tolerable strain of thin-wall shell. At first stage, workpiece large cylinder is machined to wall thickness equal to or smaller than that of adapter cone. Then local rotary swaging of larger cylinder and final machining are performed.

EFFECT: reduced metal consumption, higher quality of final products.

3 cl, 6 dwg, 1 ex

 

The invention relates to the processing of metals by pressure and can be used in the manufacture of thin-walled shells for special purposes of the Maraging steel.

A known method of manufacturing a long thin-walled shells of Maraging steel, which includes a clipping of the original piece of sheet fabrication for several operations of cold punching hollow shaped workpiece with a constant wall thickness, consisting of small and large cylinders, paired transition cone, while the operations of cold punching accompany the operation of the intermediate heat treatment, cutting edge, rinsing, applying and removing grease, etc., rotary extrusion rotary hood with thinning) shell for two operations with the degree of deformation of the large cylinder 70% and 60%, respectively, an intermediate heat treatment operation between them, the local rotary compression large cylinder inward and final processing. The method adopted for the prototype (see RTM 3-1674-85, str-190).

The disadvantages of the prototype are:

1. A large number of operations of cold punching and associated operations in-process heat treatment for stress relieving, machining to correct irregularities of the open end face, rinsing, applying and removing grease, etc. when making you the Oka hollow fittings and as a consequence, a significant consumption of auxiliary materials with high labor;

2. High consumption of metal in the manufacture of hollow fittings because of the waste of the sheet for cutting out the original piece, the destruction of the workpieces in the process of multistage cold forging, multiple pruning process ends;

3. Low quality hollow fittings:

area, close to the open end, has an increased thickness, leading to an increase in the shell ovality;

- presence on the surfaces of the hollow fittings metallurgical defects and defects, acquired in the process of its production in the subsequent rotational extrusion of the shell, especially with the degree of deformation, which is approaching the limit, promotes the formation on its surface in captivity, peeling, cheshuichatoe;

4. The high cost of sheet metal.

The invention solves the problem of improving quality and reducing material costs in the manufacture of long thin-walled shells of Maraging steel.

The technical result obtained by carrying out the invention, is the reduction of metal consumption, improving geometric accuracy and quality of the surfaces of the shell, reducing waste hollow fittings in the marriage bit is the making.

This technical result is achieved in that in the method of manufacturing a long thin-walled shells of Maraging steel, which includes the segment of the original piece, the production of hollow shaped preform of large and small cylinders, paired transition cone, rotary extrusion of long thin-walled shell in several steps with intermediate heat treatment for stress relieving, local rotary compression large cylinder inward and final processing, it is new that shaped hollow billet is manufactured by extrusion of a segment of the rod and then cutting with variable wall thickness, height, and rotation of the squeezing produced in three operations with a valid degree deformation, while in the first operation handle large cylinder.

Hollow shaped workpiece is made with a wall thickness of the large cylinder of greater wall thickness of the transition cone approximately in 2 times.

Rotary extrusion of the large cylinder in the first operation to produce wall thickness equal to or smaller wall thickness of the transition cone shaped hollow billet.

Production of hollow shaped blank by extrusion of a segment of the rod allows the use of cheaper car - ol is current, to shorten the production cycle, reduce the range of technological equipment.

The use of hollow-shaped workpiece with variable wall thickness along its height with the wall thickness of the large cylinder of greater wall thickness of the transition cone about 2 times leads to a decrease of its height, and the subsequent rotational extrusion of thin-walled shell for three operations leads to an increase in the volume of plastic processing pressure instead of cutting and, as consequence, to decrease the consumption of metal.

The cutting of hollow fittings improving its quality, because it allows to eliminate surface defects formed in the previous operations, as well as to improve the geometric accuracy of the inner diameter and thickness variation, reduce out-of-roundness.

Manufacture of thin-walled shell for three operations rotary extrusion rotary extrusion on the first operation of the large cylinder to the wall thickness of the smallest wall thickness of the transition cone reduces the thickness variation of the large cylinder, and also to reduce the degree of deformation on the next operation, which is beneficial to the geometrical accuracy of the thin-walled shell and mechanical properties of the metal.

Based on the above we can conclude that the proposed image the group has a “novelty” and “inventive step”.

The invention is illustrated by drawings, where

- 1 shows a hollow shaped blank produced by hot extrusion, consisting of a large cylinder 1, the small cylinder 2 and the transition cone 3;

- figure 2 is a hollow shaped workpiece with variable wall thickness, height, obtained by cutting the extruded preform of the large cylinder 1 with an inner diameter D and wall thickness “a0”, small cylinder 2 with an internal diameter d and wall thickness “b0” and transition cone 3 with wall thickness “C0”while “a0≈2c0”;

- 3 - the shell after the first operation rotary extrusion, consisting of a large cylinder 1 wall thickness “a1”, small cylinder 2 and the transition cone 3 with wall thickness “C0”while “a1≤C0”;

- 4 - the shell after the second operation rotary extrusion, consisting of a large cylinder 1 with an inner diameter D and wall thickness “a2”, small cylinder with an inner diameter d and wall thickness “b2” and transition cone 3 with wall thickness “c2”;

- 5 - the shell after the third operation rotary extrusion, consisting of a large cylinder 1 with an inner diameter D and wall thickness “a”of the small cylinder 2 with internal di the meter “d” wall thickness “b” and the transition cone wall thickness “C”;

- 6 - the shell after the operation of the local rotary compression of the large cylinder 1 inside and end segments of allowances.

The proposed method for the manufacture of long thin-walled shells is as follows.

The original rod cut-to-length line segments with a volume equal to the volume of extruded fittings, heated dimensional segments to a temperature of extrusion, install the heated segment is stamped, extruded hollow shaped workpiece in the form of 1 large and 2 small cylinders, paired transition cone 3 with a variable wall thickness along the height (see figure 1), by cutting the inner and outer surfaces eliminate the defective layer and get geometrically exact shaped hollow billet with a variable wall thickness along the height with the thickness of the large cylinder 1 greater wall thickness of the transition cone 3 is approximately 2 times (see figure 2). Establish a hollow shaped blank on the mandrel and produce a rotational extrusion of the large cylinder 1 wrapper to wall thickness less than or equal to the wall thickness of the transition cone (see figure 3). The membrane is washed and produce heat treatment for stress relieving. Produce a second operation rotary extrusion of the sheath along the entire length (see figure 4), the membrane is washed and subjected to heat treatment. Produce a third of the operation of rotary extrusion and get a long thin-walled shell (see 5)install the shell on the mandrel for rotary compression and implement local compression of the large cylinder to the inside (see Fig.6). After compression cut end allowances, washed shell, a thermally process and produce the final cutting of the Seating surfaces.

An example of manufacturing of long thin-walled shell with a wall thickness of the large cylinder, a=0.5 mm and a total length L=870 mm

The original rod with a diameter of 60 mm cut-to-length line segments with a volume equal to the volume of extruded fittings, heated dimensional segments to a temperature of extrusion, install the heated segment is stamped, extruded hollow shaped workpiece height 105 mm in the form of 1 large and 2 small cylinders, paired transition cone 3 (see figure 1), by cutting the inner and outer surfaces eliminate the defective layer and get geometrically exact shaped hollow billet with a variable wall thickness along the height (see figure 2) with the diameter of the large cylinder D=70 mm and wall thickness and0=7 mm, with the diameter of the small cylinder d=45 mm and a wall thickness of b0=3.5 mm and the transition cone 3 with wall thickness from0=3.5mm Establish a hollow shaped blank on the mandrel and produce a rotational extrusion of the large cylinder shell to the wall thickness of a1=3,1÷3.5 mm (less than the or equal to the wall thickness of the transition cone shaped hollow billet) (see 3). The membrane is washed and produce heat treatment for stress relieving. Produce a second operation rotary extrusion of the sheath to the wall thickness of the large cylinder and2=1.1 mm, small cylinder b2=2.2 mm and the transition cone c2=2 mm (see figure 4), the membrane is washed and thermoablative. Produce a third operation rotary extrusion and get a long thin-walled shell with a wall thickness of the large cylinder, a=0.5 mm, wall thickness of the small cylinder b=0.8 mm and wall thickness of the transition cone C=0.8 mm (see figure 5), set the shell on the mandrel for rotary compression and implement local compression of the large cylinder inside. After compression cut end allowances in size L=870 mm (see Fig.6). Then washed the shell, a thermally process and produce the final cutting of the Seating surfaces.

1. A method of manufacturing thin-walled shells of Maraging steel, including the production of hollow shaped preform of large and small cylinders, paired transition cone, step rotary extrusion of hollow fittings thin-walled shell with an intermediate heat treatment for stress relieving, local rotary compression large cylinder of thin-walled shell inside and okonchatelno the processing, characterized in that the produced hollow shaped workpiece with a variable wall thickness along the height of the cut rod extrusion and subsequent cutting and rotary extrusion is produced in three operations with acceptable degree of deformation of thin-walled shell, the first of which handle a large hollow cylinder fittings.

2. The method according to claim 1, characterized in that the hollow shaped workpiece is made with a wall thickness of the large cylinder, exceeding the wall thickness of the transition cone approximately in 2 times.

3. The method according to claim 1, characterized in that the first operation rotary extrusion processing large cylinder shaped hollow billet to produce wall thickness equal to or smaller thickness of the walls of the transition cone.



 

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