RU2282517C2 - Blank radial forging method and four-striker forging apparatus for performing the same - Google Patents

Abstract

FIELD: plastic working of metals, possibly radial forging of ingots and blanks.

SUBSTANCE: method comprises steps of forging heated blank in one set of strikers mounted in simultaneously moving holders at deformation degree 30 - 90%. Forging process includes individual procedures of squeezing blank, feeding and tilting it. Individual squeezing procedures are realized by depth whose value is determined according to given relation. Method is performed in apparatus having strikers with working surface formed by several planes; holders of upper and lower strikers with inclined sliding faces relative to which inclined sliding faces of holders of lateral strikers are moved. Lateral strikers are coupled with holders of upper and lower strikers through eight guides with П-shaped cross section. Strikers have cross sections with working portions in the form of isosceles trapezium. Forming lock joint inner faces of П-shaped guides and embraced by them faces of holders of strikers are inclined by angle 0 - 170° relative to mounting plane of guide to striker holder.

EFFECT: improved efficiency and quality of forging, improved wear resistance of tools.

6 cl, 10 dwg, 1 ex, 3 tbl

Description

The invention relates to the field of metal forming, and in particular to methods for radial forging of ingots and billets on hydraulic forging presses or radial forging machines equipped with four-side forging devices, and designs of four-side forging devices.

The invention can be used in the engineering and metallurgical industries in the manufacture of forgings from various steels and alloys in forging shops with hydraulic forging presses or radial forging machines.

A known method of forging workpieces in a four-sided forging device, comprising compressing the workpiece with two pairs of dies in the radial direction with the application of the forces of normal compression and shear, feeding and tilting of the workpiece from the side of the dies. Forging by this method is carried out in three stages: the main, intermediate and final, while at the main stage of crimping is performed with the introduction of the side surfaces of the strikers into the body of the workpiece, and at the main and intermediate stages, the workpiece after each crimping is turned over at an angle of 15-45 °, this at the final stage, the workpiece is crimped with an angle of coverage of the strikers of 280-350 ° and tilting after each feed in the same direction as in the previous stages, and the feed of the workpiece is assigned from the ratio

where L is the width of the working surface of the strikers in the direction of the feed axis of the workpiece;

α is the pitch angle of the workpiece;

π is a constant value (UA 34978 C2, B 21 J 1/04, B 21 J 13/02, 07/15/2003).

This method provides high precision forgings with high surface quality.

However, the known method of forging blanks does not provide high productivity of the process, as well as the quality of the metal forgings, since due to poor deformation of the cast structure of the metal it is difficult to obtain its high quality over the entire cross section of the ingot.

A four-sided forging device is known, consisting of holders of the upper and lower strikers with inclined surfaces, kinematically using guides - links - two holders of side strikers connected to them with inclined surfaces corresponding to the inclined surfaces of the upper and lower holders and four strikers attached to the respective holders ( Japanese Application No. 58-12088, B 21 J 9/06, 9/02, 13/2, 07.03.83).

This device provides synchronous compression of the workpiece from four sides in the manufacture of forgings of round and square cross-section.

But at the same time, the design of its guide links does not provide high reliability and durability of the device, as well as high accuracy of the obtained forgings.

Closest to the proposed four-sided forging device is the device according to the patent of Ukraine No. 29183 (B 21 J 1/04, 10.16.2000), containing strikers, the working surface of each of which is formed by several planes, holders of the upper and lower strikers with inclined sliding planes and holders side strikers made with inclined glide planes corresponding to the aforementioned glide planes of the holders of the upper and lower strikers, mounted to move relative to the holders of the upper o and lower pins and the associated guide means mounted on the holders.

The well-known four-sided forging device provides forgings with high dimensional accuracy in cross section.

However, the known four-sided forging device does not provide high performance of the process, is characterized by increased wear of the sliding planes, as well as the possibility of jamming the holders of the side strikers in the guides.

The objective of the invention is to provide a method for radial forging of workpieces and a four-flange forging device for its implementation, providing an increase in the quality of metal forgings, productivity of the forging process and increase the resistance of sliding planes.

The technical result is achieved by the fact that, in contrast to the known method of radial forging of workpieces in a four-sided forging device, the strikers of which are mounted on holders that can synchronously move and are guided kinematically connected by mating inclined sliding planes, including single compression of the heated workpiece with the introduction of side surfaces strikers in the body of the workpiece, feed and tilting, in the proposed method, forging is carried out in one set of strikers with st enyu deformation 30-99%, with individual compression preform operate depth δ, defined by the following formula:

δ = (0.4-2.4) × h,

where h is the height of the working section of the striker.

The technical result is also achieved by the fact that the breeding of the strikers of the forging device before a single compression of the workpiece is carried out subject to the following ratio:

l _k / l≥0.20,

where l _k is the length of the contact pads of the mating inclined sliding planes of the holders of the strikers;

l is the length of the guides,

and single compression of the workpiece is carried out subject to the ratio

l _k / l≥0.33.

The achievement of the technical result is also facilitated by the fact that lubricants are periodically applied to the mating inclined sliding planes of the die holders during operation of the forging device.

To achieve the named technical result in a four-sided forging device containing strikers, the working surface of each of which is formed by several planes, holders of the upper and lower strikers with inclined planes of sliding and holders of side strikers made with inclined planes of glide corresponding to the mentioned planes of glide of the holders of the upper and lower strikers installed with the possibility of movement relative to the holders of the upper and lower strikers and associated with them The only new feature of guides mounted on the holders is that the holders of the side strikers are connected to the holders of the upper and lower strikers by means of eight guides of a U-shaped cross section, the inner planes of which are made covering the planes of the strikers holders with the formation of a locking joint, the strikers are made in cross section work areas in the form of an isosceles trapezoid facing the tops of the workpiece, while when the strikers are closed, these work areas form a contour s, which are interconnected by the following relation:

F ₁ / F ₂ = 1.8-10,

where F ₁ - the area of the contour, limited by the bases of the trapezoid with the closed position of the strikers;

F ₂ - the area of the contour bounded by the vertices of the trapezoid,

and the indicated inner planes of the U-shaped guides and the planes of the strikers holders covered by them are located at an angle α = 0-170 ° to the plane of fastening of the guide on the striker holder.

The achievement of the technical result is also facilitated by the fact that, depending on the design features of the device manufactured for pressing specific workpieces, simplifying its assembly and operation:

- the guides can be fixed on the holders of the upper and lower strikers, and the plane of fastening of each guide is perpendicular to the inclined planes of glide of the holders of the strikers;

- the guides can be fixed on the holders of the side strikers, and the plane of fastening of each guide is perpendicular to the inclined sliding planes of the holders of the strikers.

The inventive method of radial forging, four-sided forging device for its implementation are illustrated in figures 1-10.

Figure 1 presents a General view of the four-forging device in statics (when reducing strikers); figure 2 is a section aa of figure 1; figure 3 - section bb In figure 1 (option I); figure 4 - section bb In figure 1 (option II); figure 5 - section bb In figure 1 (option III); figure 6 is a section CC of figure 1; figure 7 presents a General view of the four-forging device in dynamics (during compression of the workpiece); on Fig - scheme of compression of the workpiece by four strikers with incomplete implementation of the lateral planes of the strikers in the body of the workpiece; figure 9 is a diagram of the compression of the workpiece by four strikers with the full implementation of the lateral planes of the strikers in the body of the workpiece; figure 10 - two stages of compression of the workpiece by four strikers with tilting of the latter at an angle β.

Four-forging device consists of the holder of the upper striker 1, the holder of the lower striker 2, the holders of the side strikers 3, 4, strikers 5-8, guides 9-12 (Fig. 1). The forging device is attached to the upper plate 13 mounted on the movable crosshead of the press, as well as to the lower plate 14 using grooves, for example, dovetail or with special clamps (not shown).

The holders 3, 4 of the side strikers 5, 7 have inclined sliding planes corresponding to the inclined sliding planes of the holders 1, 2 of the upper 6 and lower 8 strikers and are kinematically connected with them by means of guides of a U-shaped cross section 9-12, providing reciprocating movements of the holders side strikers 3, 4 (Figs. 1-5, 7). The strikers 5-8 have in cross-section the working sections "abcd", each in the form of an isosceles trapezoid, with the top "dc" facing the workpiece (shown by a dotted line in Figs. 7-10). The lateral planes "ad" and "cb" (Figs. 1, 8, 9) are actively involved in the formation of the cross section of the forgings (Figs. 8-10). In this case, the geometric dimensions of the trapezoid are selected based on the ratio

F ₁ / F ₂ = 1.8 ÷ 10,

where F ₁ is the contour area limited by the trapezoid bases;

F ₂ - the area of the contour bounded by the vertices of the trapezoid.

1, the area F _{1 is} denoted by the letters abba, and the area F ₂ by the letters dcc'd '.

When the ratio F ₁ / F ₂ <1.8, the required degree of deformation of the workpiece (ε = 30%) is not ensured in one set of dies with the introduction of the side surfaces of the dies in the body of the workpiece, and high productivity of the forging process is also not achieved.

When the ratio F ₁ / F ₂ > 10, the dimensions of the device significantly increase, which is not rational.

As shown in FIGS. 2-5, the inner surfaces (planes) of the guides of the U-shaped cross-section 9-12, as well as the surfaces (planes) of the holders of the strikers covered by them “locked” (with the possibility of relative longitudinal movement), are each angled α = 0 ÷ 170 ° to the plane of fastening of the guide on the striker holder.

This ensures a smooth, without distortion, sliding of the holders of the side strikers relative to the holders of the upper and lower strikers. Figure 5 shows the case of run guides with an angle α = 0 °.

At angles α> 0 ÷ 170 °, distortions of the holders of the side strikers, their jamming and breakage of the guides are possible.

There are two options for securing the U-shaped guides.

The first, known, option for attaching the guides is that the guide is fixedly mounted on the holder of the upper or lower strikers, and the inner surface of the guide is movably in contact with the surface covered by it, made on the holder of the side striker (Figs. 3, 4, 5) (Ukrainian patent No. 21986 A, B 21 J 13/02, 04/30/98). However, not in all cases, such a fastening of the guides provides the required high level of assembly of the device, and consequently, a long overhaul life.

In the claimed design of the four-sided forging device, a second option for securing the guides is possible, namely, the guide is mounted on the side striker holder, and its inner surface is movably in contact with the surface made on the holder of the upper or lower striker (Fig. 2). This allows more accurate assembly of the device, which increases the abrasion resistance of the inclined planes of the holders of the strikers, which leads to an increase in the overhaul life of the device.

The four-sided forging device is as follows.

When lifting the movable crosshead of the press with the top plate 13 up, the holder of the upper striker 1 with the striker 6 also moves up and at the same time, using guides 9-12, pushes the holders of the side strippers 3, 4 to the sides, opening the working space of the device (Fig. 7).

Then the workpiece (Fig. 7 shows a dashed cross section of the workpiece) using a manipulator is fed into the working area of the device. After that, the working stroke of the press is switched on, in which its movable crosshead moves the holder of the upper striker 1 together with the striker 6 towards the workpiece and, together with the striker 8, compresses it in a vertical plane. At the same time, using guides 9-12 and mating inclined planes, the holder of the upper striker 1 moves the holders 3, 4 of the side strikers 5, 7, which compress it in the radial and tangential directions, towards the workpiece. After completing the compression of the workpiece, the press beam with the upper plate 13 moves the holder of the upper striker 1 upward, revealing the device, and the compression cycle is repeated (Fig. 7).

The inventive method of radial forging of billets by four strikers in the claimed design of the four-billet forging device is as follows.

First, the forging complex — a radial forging machine or a hydraulic forging press with a four-sided forging device — is prepared for operation. To do this, before forging, four identical strikers 5-8 are installed in the working space of the RCM or forging device, placing them in pairs in two mutually perpendicular planes "nn" and "mm" (Fig. 8).

Heated to a forging temperature billet in the form of an ingot, cast or pre-deformed billet, is removed from the heating furnace and using the manipulator is fed into the working area of the forging unit, where it is crimped by strikers 5-8 with the introduction of the side surfaces of the strikers into the body of the billet (Fig. 8 -10). In this case, single compression of the workpiece is performed by the value

δ = (0.4-2.4) h

where h is the height of the working section of the striker.

When the workpiece is compressed less than 0.4 h, a high productivity of the process is not ensured, and a high quality of metal in the axial zone of the forging is not achieved. When the workpiece is compressed over 2.4 h, cakes on the forging surface are possible, since in this case the strikers will be introduced into the forging body not only by the side planes of the working sections, but also by the side planes of the base of the strikers. Figure 9 shows the compression pattern of the four strikers with the maximum possible implementation of the strikers in the body of the workpiece. In this case

δ / 2 = 1.2h or δ = 2.4h.

After each single compression, the workpiece is fed and tilted at an angle β with overlapping of the crimped sections until the entire surface is completely crimped (Fig. 10).

The inventive method of crimping a workpiece with four strikers with the introduction of the side surfaces of these strikers with a single squeezing δ = (0.4-2.4) · h allows forging a workpiece with a degree of deformation ε = 30-99% from one heating of the workpiece in one set of strikers and get the quality of the metal above known analogues.

The calculation of the degree of deformation is carried out according to the formula

where F ₀ , F ₁ - the cross-sectional area of the workpiece and finished forgings, respectively.

When forging a workpiece with a degree of deformation ε <30%, high metal quality is not ensured, and when forging with a degree of deformation ε> 99.0%, the workpiece cools below the temperature of plastic deformation, which leads to the need to stop the forging process.

In this case, the opening of the strikers before crimping the workpiece is performed subject to the ratio

l _k / l≥0.20,

where l _k is the length of the contact pads of the mating inclined sliding planes of the holders of the strikers;

l is the length of the guides (Fig.7).

With a ratio of l _k / l <0.20, the holders of the side strikers in the guides of the U-shaped cross-section may be skewed, jammed and the guides may break.

The operation of the device in the process of crimping the workpiece is made subject to the ratio

l _k / l≥0.33.

When the ratio l _k / l <0.33, the wear of the sliding planes of the die holders is significantly increased and, accordingly, the overhaul time of the device and, as a result, the production volumes of forgings during this period are reduced.

An example of the method

Before starting work, a four-flange forging device was prepared for operation by installing strikers with geometric dimensions on the holders, depending on the diameter of the forging. A lubricant layer based on molybdenum disulfite was applied to adjacent inclined sliding surfaces of the strikers and guides, which ensures the normal operation of the device for one shift (8 hours).

An ingot weighing 1 ton, 440 mm in diameter from R6M5FZ high-speed steel was heated in a gas chamber furnace to a temperature of 1150 ° C and forged on a hydraulic forging press with a force of 20 MN in a four-forging forging device of the claimed design forged with a diameter of 105 mm. Forging was carried out in one set of strikers for one ingot heating.

The degree of deformation was

Single ingot compression was performed with the value δ = 120-220 mm, which corresponded to the ratio

δ / h = 0.55-1.6,

where h is the height of the working section of the striker.

In the forging process, the lateral planes of the strikers were introduced into the body of the workpiece.

In the used four-side forging device, the following ratios were maintained:

F ₁ / F ₂ = 3.2,

and the angle α = 140 °.

The disclosure of the strikers of the four-sided forging device was carried out (before loading the workpiece), maintaining the ratio

l _k / l = 0.26-0.48,

and compression of the workpiece was carried out subject to the ratio

l _k / l = 0.38-0.43.

The productivity of the forging process was 2230 kg / h.

The quality of the metal was evaluated by a carbide inhomogeneity score for three zones of the forging cross section:

1st - 5 mm from the forging surface;

2nd - the middle of the radius of the cross section of the forging (1 / 2R);

3rd - axial zone of forging.

At the surface, carbide heterogeneity corresponded to 3 points, to 1 / 2R - 5 points, and in the axial - 6 points.

On the inclined planes of the slide holder holders strikers and deep scratches were absent.

For comparison, an ingot with a weight of 1 ton and a diameter of 440 mm was forged from R6M5FZ steel according to the prototype method in the well-known four-side forging device into forgings with a diameter of 105 mm.

The productivity of the forging process according to the prototype method was 1560 kg / h, and the quality of the metal, estimated by the carbide inhomogeneity score:

- at the forging surface - 4 points;

- at half the radius of the cross section - 7 points;

- in the axial zone of the forgings - 7-8 points.

On the inclined planes of the slide holders holders appeared deep scratches, risks.

The results of the experiments with other process and device parameters are presented in Table 1-3.

Analysis of the data given in table 1-3, shows that the quality of the metal forgings obtained by the claimed method in the claimed design of the four-flange forging device (estimated by the carbide inhomogeneity score) is higher than the quality of the metal forgings obtained by the prototype method. For a specific example of the manufacture of forgings from high-speed steel R6M5FZ, the decrease in carbide heterogeneity was 1-2 points.

The productivity of the forging process by the patented method increased by 8.3-57.7%, and the resistance of the sliding planes increased by 2.4 times. In this case, during operation of the patented device, its jamming and breakage of the guides were excluded.

Table 1 Experience number The degree of deformation, ε,% The ratio δ / h, unity Δ = b.s. (guest) - b.k.s. (experience), score Productivity, kg / h Note one 24 0.5 0 1570 2 thirty 0.7 0 1690 3 75 1.3 2 2340

Continuation of table 1 Experience number The degree of deformation, ε,% The ratio δ / h, unity Δ = b.s. (guest) - b.k.s. (experience), score Productivity, kg / h Note four 99 1.3 2 2460 5 99.3 1.3 - - The workpiece is not docked, because cooled down 6 65 0.4 0 1760 7 75 2,4 2 2390 8 75 2,5 Marriage, forging formed 9 prototype 0 1560 * Note: b.s. (GOST) - allowable carbide heterogeneity score according to GOST 19265-73; bc (experience) - carbide heterogeneity score obtained during this experiment. table 2 Experience number F ₁ / F ₂ , single <α, deg. Produces. process, kg / h Assessment of the operability and technological capabilities of the device one 5 90 2460 The device provides a process of forging blanks by the patented method without scoring on the sliding planes of the holders of the strikers 2 5 90 2300 - // - 3 5 90 2300 Scoring on the slip planes four 1.7 90 1500 Slow process performance 5 10 90 2220 Stable forging process without scoring on the sliding planes of the die holders 6 eleven 90 2310 Significantly increase the dimensions of the device 7 5 0 2250 Stable forging process, no scoring on sliding planes

Continuation of table 2 Experience number F ₁ / F ₂ , single <α, deg. Produces. process, kg / h Assessment of the operability and technological capabilities of the device 8 5 170 2320 Stable forging process, no scoring on sliding planes 9 5 175 - Jamming device 10 prototype - - 1560 Scoring on the sliding planes of the striker holders Table 3 Experience number l _k / l The volume of forgings forged between repairs of the sliding planes of the die holders, t Note one 0.19 - Jammed device and broken guides 2 0.25 1100 Significant wear on sliding surfaces 3 0.33 2500 Depreciation of the slip planes is negligible, minor repairs four 0.40 2500 - // - 5 prototype - 1050 Significant wear on sliding surfaces

Claims (6)

1. The method of radial forging of workpieces in a four-sided forging device, the strikers of which are mounted on holders with the possibility of synchronous movement and through guides kinematically connected by mating inclined sliding planes, including single compression of the heated workpiece with the introduction of the side surfaces of the strikers in the body of the workpiece, feed and turning , characterized in that the forging is carried out in one set of strikers with a degree of deformation of 30-99%, while the unit compresses the workpiece m depth δ defined by the formula δ = (0.4-2.4) h where h is the height of the working section of the striker. 2. The method according to claim 1, characterized in that the breeding of the strikers of the forging device before a single compression of the workpiece is made subject to the following ratio: l _to / l≥0.20, where l _to - the length of the contact pads of the mating inclined planes of sliding holders holders; l is the length of the guides, and single compression of the workpiece is carried out subject to the ratio l _to / l≥0.33. 3. The method according to claim 1 or 2, characterized in that grease is periodically applied to the mating inclined sliding planes of the die holders during operation of the forging device. 4. Four-sided forging device comprising strikers, the working surface of each of which is formed by several planes, holders of the upper and lower strikers with inclined planes of glide and holders of side strikers made with inclined planes of glide corresponding to the aforementioned planes of glide of holders of the upper and lower strikers, installed with the ability to move relative to the holders of the upper and lower strikers and associated with them by means of guides mounted on the holders, about characterized by the fact that the holders of the side strikers are connected to the holders of the upper and lower strikers by means of eight guides of a U-shaped cross section, the inner planes of which are made covering the planes of the holders of the strikers with the formation of a locking joint, the strikers are made in cross section with working sections in the form of an isosceles trapezoid facing vertices to the workpiece, while in the closed position of the strikers, the said working sections form contours, interconnected by the following relationship: F ₁ / F ₂ = 1.8-10, where F ₁ - the area of the contour, limited by the bases of the trapezoid with the closed position of the strikers; F ₂ - the area of the contour bounded by the vertices of the trapezoid, and the indicated inner planes of the U-shaped guides and the planes of the strikers holders covered by them are located at an angle α = 0-170 ° to the plane of fastening of the guide on the striker holder. 5. The device according to claim 4, characterized in that the guides are mounted on the holders of the upper and lower strikers, and the fastening plane of each guide is perpendicular to the inclined planes of sliding of the strikers holders. 6. The device according to claim 4, characterized in that the guides are fixed on the holders of the side strikers, and the plane of fastening of each guide is perpendicular to the inclined planes of sliding of the holders of the strikers.

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