RU2655527C1 - Method of obtaining round profiles - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention refers to treatment of metals by pressure and can be used during the production of circular profiles by means of multi-pass radial forging. Initial blank with the square cross-section is subjected to cobbing simultaneously with two mutually perpendicular pairs of backups. Mentioned pairs are disposed with the displacement of their working surfaces relative to each other along the forging axis by the amount greater than the length of the working surface of the backup. There is the cutout groove with lateral surfaces, which are inclined to each other at an obtuse angle, on the working surface of the backups. Cogging of the initial workpiece is performed diagonally in order to manufacture the octagonal blank. Then, the resulting octagonal blank is cogged and rotated around the forging axis prior to each cogging until the circular profile is obtained.

EFFECT: as a result, the energy consumption is reduced, the technological capabilities are increased, the resistance of the backups is improved and the increased quality of the round profiles is obtained.

1 cl, 6 dwg

Description

The invention relates to the processing of metals by pressure, and in particular to methods for producing round profiles using radial forging.

A known method of producing round profiles from a square billet radial forging [Forging on radial crimping machines / Century A. Tyurin, V.A. Lazorkin, I.A. Pospelov et al. - M.: Mechanical Engineering, 1990. - S. 26, 206-208]. In this method, round profiles are obtained by multi-pass radial forging by two mutually perpendicular pairs of strikers having a working surface with a flat brook. First carry out the compression on the diagonal of the square billet without turning it. Then radial forging is carried out with rotation of the workpiece before each crimping to obtain a round profile.

The disadvantages of this method are:

1. Rapid wear of the working surface of the strikers in its middle part due to the need for “knocked down" the edges of a square billet before forming a round profile. In this case, the average worn part of the working surface of the strikers then forms the resulting round profile, reducing its quality. The wear of the working surface of the strikers is due to the fact that the edges of the square, having an angle between the faces equal to 90 °, quickly cool down and therefore have a higher resistance to plastic deformation than the rest of the workpiece. The rapid wear of the working surface of the strikers is an indicator of their low resistance.

2. Spontaneous rotation of a square billet (stall) when forged on a diagonal into a round profile in strikers having a working surface with a flat stream [I.Ya. Tarnovsky. Shaping during plastic processing of metals (forging and rolling). M .; Metallurgizdat, 1954. - S. 516], leading to a decrease in the quality of the obtained round profiles.

3. High non-uniformity of deformation during forging of a square billet on a diagonal in strikers having a working surface with a flat stream, which leads to significant transverse deformation of the metal (broadening). This requires additional energy consumption for deformation during the formation of a round profile. High non-uniformity of deformation also leads to the appearance in the axial zone of the workpiece of maximum longitudinal tensile stresses, which are the cause of the discontinuity of the metal of the workpiece, especially special steels [Forging on radial crimping machines / B.A. Tyurin, V.A. Lazorkin, I.A. Pospelov et al. - M.: Mechanical Engineering, 1990. - S. 98].

4. When forming a round profile, the contact of the workpiece with the working surface of the striker is carried out on its limited width, which reduces the displaceable metal volume in one stroke of the strikers, i.e. "Exhaust" ability of the method. This increases the energy consumption for shaping.

5. The possibility of crimping the corners (ribs) of a square billet without turning it to obtain an octagonal profile with a face not exceeding the minimum diameter of the resulting round profile. This is due to the fact that the working surfaces of all four strikers are in the same plane without their displacement. In this case, based on geometric conditions, the ratio between the side of the original square billet used and the diameter of the resulting round profile cannot exceed √2, which is a criterion for the limited technological capabilities of the method.

6. Limited technological capabilities of the method for the minimum diameter of the finished profiles. The minimum diameter of the finished profiles cannot be commensurate with the progress of the strikers, because ready-made profiles with a maximum clearance between the strikers during forging can fall into the side connectors between the strikers. Because of this, a “bite” of the round profile occurs on the side edges of the strikers, leading to a decrease in the quality of the finished profiles and emergency situations.

 Thus, the main disadvantages of this method are the high energy consumption for shaping, low durability of the strikers, low quality of the obtained round profiles and limited technological capabilities.

Closest to the proposed solution in terms of technical nature and the achieved effect is the method adopted for prototype production of round profiles with multi-pass radial forging simultaneously by two mutually perpendicular pairs of strikers, when the working surfaces are displaced from mutually perpendicular strikers relative to each other along the forging axis by an amount exceeding the length the working surface of the striker [Forging on radial crimping machines. / B.A. Tyurin, V.A. Lazorkin, I.A. Pospelov et al. - M.: Mechanical Engineering, 1990. - S. 27]. This method can be used to obtain round profiles from a square billet.

This method has no restrictions on the size of the initial blanks and the resulting profiles, i.e. It has no drawbacks associated with limited technological capabilities in obtaining round profiles according to p. 5 and 6 of the above analogue. At the same time, he remains inherent disadvantages under paragraphs 1, 2, 3, 4 of the above analogue.

Thus, the main disadvantages of the method adopted as a prototype are the high energy consumption for metal forming, the limited durability of the strikers and the low quality of the obtained round profiles.

The objective of the invention is to reduce energy consumption, expanding technological capabilities for the assortment of the obtained profiles, increasing the durability of the strikers and the quality of the obtained round profiles.

The problem is achieved in that in the inventive method for producing round profiles with multi-pass radial forging, including crimping the original workpiece with a square cross section at the same time by two mutually perpendicular pairs of the strikers made with a working surface, while said pair of strikers with an offset of their working surfaces relative to each other along the forging axis by an amount exceeding the length of the working surface of the striker, according to the invention, strippers having a working surface are used Using a notched brook with lateral surfaces inclined to each other at an obtuse angle, they compress the original workpiece with a square cross-section along the diagonal of the aforementioned section to obtain an octagonal workpiece, after which they compress the resulting octagonal workpiece with its rotation around the forging axis before each compression to obtain round profile.

According to the invention, in the particular case, strikers are used whose lateral surfaces of the notch stream are inclined to each other at an angle of 135 °.

Compression of the initial workpiece with a square cross-section diagonally by strikers having a notched stream with side surfaces inclined to each other at an obtuse angle γ on the working surface allows you to get the wrong octagonal profile with adjacent inner angles equal to γ and 270 ° -γ. The sum of the inner adjacent corners of such an octagonal profile is 270 °.

When compressing the initial workpiece with a square cross-section at the same time by two mutually perpendicular pairs of strikers having a notched stream with side surfaces inclined to each other at an angle of 135 ° on the working surface, it is possible to obtain a regular octagonal profile with the same internal angles of 135 °.

Compression of the original workpiece with a square cross-section diagonally by the indicated dies provides:

- a stable position of the square billet without its rotation (stall) around the axis of the forging during compression;

- a high coefficient of yield due to lateral support of the metal, which reduces the broadening of the metal of the workpiece and provides a deformation scheme for comprehensive compression of the metal [V.I. Kraynov. Technology of forging and die forging processes: lecture notes - Chelyabinsk: SUSU Publishing House, 2007, p. 68];

- the lack of high non-uniformity of deformation, eliminating the appearance of tensile stresses in the axial zone of the workpiece and violation of the continuity of the metal of the workpiece;

- contact of the edges of the square billet with the tops of the cut-out streams of the working surface of the strikers with a gradual transition to their lateral surfaces.

The main effect of the application of such technological operations is to reduce the energy consumption for shaping the workpiece, improve the quality of the resulting octagonal profiles, which are workpieces for the subsequent production of round profiles, reduce wear on the working surface of the strikers. Reducing the wear of the working surface of the strikers at the stage of forming an octagonal profile from a square billet provides an increase in the quality of finished round profiles.

A turn before each subsequent compression of the octagonal profile formed at the preliminary stage allows to obtain a round profile. The use for forming a circular profile of strikers having a notched stream on the working surface with side surfaces inclined to each other at an obtuse angle γ provides a deformation scheme for comprehensive compression of the metal, in which the side surfaces of the notched streams are formed, which did not participate in the deformation of acute square angles blanks. In this case, the lateral surfaces of the cut brooks of each striker forms two centers of deformation with the workpiece. This at the same time positively affects the quality of the finished round profiles and intensifies the process of metal forming, reduces its broadening and, as a result, reduces the energy consumption for forming the workpiece.

The use of strikers having a notched stream on the working surface with side surfaces inclined to each other at an angle of 135 ° has a positive effect on the formation of a round profile. This is due to the fact that the regular octagonal profile obtained by such strikers has the same distance between opposite ribs, which provides the same conditions for the deformation of the edges of the octagonal profile when receiving a round profile from it.

In addition, the use of the well-known technical solution — displacement of the working surfaces of mutually perpendicular strikers relative to each other along the forging axis by an amount exceeding the length of the striker working surface, for a new purpose, namely to obtain round profiles, provides the following effect:

- removes restrictions on the ratio of the size of the cross section of the original square billet and the resulting round profiles;

- removes restrictions on the minimum size of the cross section of the obtained round profiles, because with almost any applied stroke of the strikers during forging, round profiles cannot fall into the side connectors between the strikers.

Due to this, the technological capabilities of the method for producing round profiles from a square billet are expanded.

It follows that the use of the proposed method ensures the production of a wide range of initial square blanks of high-quality round profiles of virtually unlimited assortment while ensuring high durability of the tool (strikers) and limited energy consumption.

Thus, the application of the proposed method provides a reduction in energy consumption, expansion of technological capabilities, increasing the durability of the strikers and the quality of the obtained round profiles.

The proposed method of radial forging of round profiles is illustrated in the drawings, in which the side surfaces of the notched stream are inclined to each other at an angle of 135 °. With this angle of inclination of the side surfaces of the notched stream, the formation of a square octagonal profile from the square blank at the first stage of implementation of the proposed method is ensured.

In FIG. Figure 1 shows a section along two-way strikers of one pair and a view of a two-way striker of another pair having a notched stream on the working surface and the clamping jaws of the manipulators during compression of the square initial billet to the diagonal to obtain the correct octagonal profile.

In FIG. 2 shows a view of the square initial blank and the strikers in the direction of supply of the blank during compression of the square initial blank to the diagonal to obtain a “large” regular octagonal profile.

In FIG. Figure 3 shows a section through two-way strikers of one pair and a view of a two-way striker of another pair having a notched stream on the working surface and the clamping jaws of the manipulators during compression of the octagonal workpiece with its rotation before each compression around the forging axis to obtain a round profile.

In FIG. 4 shows a view of the octagonal workpiece and the strikers in the direction of supply of the workpiece during compression of the octagonal workpiece with its rotation before each compression around the axis of the forging to obtain a "large" round profile.

In FIG. 5 shows a view of the octagonal and round billets, the strikers in the direction of feeding the billet during compression of the octagonal or round billets to obtain a “fine” regular octagonal profile.

In FIG. 6 shows a view of the octagonal and round billets, the strikers in the direction of supply of the billet during compression of the octagonal or round billets with their rotation before each compression around the axis of the forging to obtain a "small" round profile.

Obtaining round profiles by multi-pass radial forging is carried out by two mutually perpendicular pairs of double-entry strikers, in which each striker has two working surfaces, allowing deformation both during forward and backward movement of the workpiece (Fig. 1-6). Two pairs of strikers 1, 2, 3 and 4 have a notched stream on the working surface with side surfaces inclined to each other at an angle of 135 °. The working surfaces of mutually perpendicular strikers are displaced along the forging axis by an amount S exceeding the length of the working surface of the striker L (Fig. 1). The workpiece is held along the forging axis, fed into the strikers and rotated around the forged axis by two manipulators A and B (the clamping jaws of the manipulators are shown in the figures for simplicity).

Obtaining round profiles with multi-pass radial forging is carried out in several passes. The number of passes is determined by the ratio of the cross-sectional dimensions of the original square billet and the finished round profile. In this example, in order to reduce the number of illustrations, we consider obtaining round profiles in two and four passes. In this case, intermediate octagonal profiles were obtained in one and two passes.

The initial preform 5 has a square cross section (Fig. 1, 2). Before the first pass, the square billet 5 is clamped by the jaws of manipulator A, fed by this manipulator into the strikers 1-4 with two opposite ribs directed to the tops of the cut-out streams of the working surfaces of the strikers 1-4 (on the diagonal), and compression begins with two pairs of strikers 1-4. Due to the reciprocating movement (shown by vertical arrows), the pair of strikers 1-4 carry out the compression of the square initial workpiece along its diagonals. In the process of the first pass, the workpiece 5 from the manipulator A is transferred to the manipulator B, which downloads the implementation of this passage (Fig. 1) to obtain an octagonal profile with internal angles equal to 135 °.

In the second pass (Fig. 3), using the manipulator B, before each crimping, a rotation is made around the forging axis of the regular octagonal profile formed in the first pass to obtain a round profile (Fig. 4). In the process of the second pass, the workpiece 5 from the manipulator B is transferred to the manipulator A, which downloads the implementation of this passage with the receipt of a round profile.

Obtaining a round profile of a smaller cross-section, depending on the required deformation conditions, can be carried out according to the following three technological schemes.

According to the first scheme, the correct octagonal profile obtained in the first pass is subjected, similarly to the first pass, to further deformation in strikers 1-4 with the required reduction in the gap between them to obtain a regular octagonal profile with a smaller cross section (Fig. 5). Then, similarly to the second pass, the obtained regular octagonal profile is compressed in strikers 1-4 with its rotation before each compression around the forging axis to obtain a round profile (Fig. 6).

According to the second scheme, the round profile obtained in the second pass is subjected, similarly to the second pass, to further deformation in the strikers 1-4 with the required reduction of the gap between them to obtain a round profile of a smaller cross section (Fig. 6).

According to the third scheme, the round profile obtained in the second pass is subjected, similarly to the first pass, to deformation in strikers 1-4 with the required reduction in the gap between them to obtain a regular octagonal profile with a smaller cross section (Fig. 5). Then, similarly to the second pass, a round profile of a smaller cross section is obtained (Fig. 6).

Thus, the application of the proposed method provides for obtaining from a square initial blank a wide range of round profiles of the desired cross section.

The proposed method was tested during hot forging of round profiles ∅70, 60 and 50 mm from a square billet of 80 mm on a radial forging machine SKK-14 of the Austrian company GFM, installed at one of the enterprises in Chelyabinsk. In this case, two mutually perpendicular pairs of strikers were used, which had a notched stream on the working surface with side surfaces inclined to each other at an angle of 135 °. The strikers had calibrating sections parallel to the forging axis, and crimping sections inclined at an angle of 12 ° to the forging axis. The supply of the workpiece in one stroke of the strikers was 8 mm. The number of strokes of the strikers per minute is 800. The displacement of the working surfaces of the pairs of strikers along the forging axis was S = 64 mm. The length of the working surface of the striker L = 58 mm.

Obtaining round profiles ∅70, 60 and 50 mm was carried out according to the following technological scheme. First, without turning the workpiece, the correct octagonal profiles with internal angles of 135 ° were obtained. The correct octagonal profile 70 is obtained in four passes. The correct octagonal profile 60 is obtained in five passes. The correct octagonal profile 50 is obtained in six passes. Then, with the rotation of the obtained regular octagonal profiles around the forging axis, before each compression by an angle of 17.5 ° in one pass, round profiles of ∅70, 60 and 50 mm, respectively, were obtained.

The experimental work confirmed the effectiveness of the proposed method, namely, obtaining high-quality round profiles ∅70, 60 and 50 mm from a square initial blank of 80 mm.

Claims (2)

1. A method of producing round profiles with multi-pass radial forging, comprising crimping the initial workpiece with a square cross section at the same time with two mutually perpendicular pairs of strikers made with a working surface, said pairs of strikers having an offset of their working surfaces relative to each other along the forging axis by an amount exceeding the length of the working surface of the striker, characterized in that the strikers having a cut stream with side surfaces on the working surface are inclined facing each other at an obtuse angle, they compress the initial billet with a square cross-section diagonally of the aforementioned section to produce an octagonal billet, after which the resulting octahedral billet is crimped with its rotation around the forging axis before each crimping to obtain a round profile. 2. The method according to p. 1, characterized in that they use strikers whose side surfaces of the notch stream are inclined to each other at an angle of 135 °.

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