Variable angle cross wedge rolling die

Abstract

The application discloses a variable-angle cross wedge rolling die, which comprises a wedge-in section, a widening section and a finishing section, the forming angle continuously changes from the wedge-in section to the widening section, and the widening angle continuously changes from the wedge-in section to the widening section. The variable-angle cross wedge rolling die provided by the application can change the forming angle and the widening angle simultaneously, the surface damage of a rolled piece rolled by the variable-angle cross wedge rolling die is effectively improved, and the possibility of the core cracking of the rolled piece is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of cross wedge rolling, and particularly relates to a variable-angle cross wedge rolling die. BACKGROUND

[0002] Cross wedge rolling is a new process for forming shaft parts, in which a rolled piece is placed between two rollers with wedge-shaped dies, the rollers rotate in the same direction, and the blank is formed into various stepped shaft parts under the action of the wedge faces of the rollers. Cross wedge rolling deformation includes radial compression and axial extension, and has the advantages of high production efficiency and low cost.

[0003] In the existing cross wedge rolling technology, the two main process parameters of the cross wedge rolling die are the forming angle alpha and the widening angle beta. Generally, the forming angle alpha and the widening angle beta of each single wedge are fixed values. The wedge-in section is naturally formed after the forming angle alpha and the widening angle beta are selected. However, the appearance of the wedge-in section and the formation of the Archimedes spiral of the roller-type cross wedge rolling completely depend on the matching of the two parameters, and the process parameters of the wedge cannot be changed and also need to consider the deformation of the wedge-in section and the widening section. The adjustment window of the control parameters for the forming quality, especially the core quality, is limited. SUMMARY

[0004] The purpose of the present application is to provide a variable-angle cross wedge rolling die, in which the forming angle and the widening angle are simultaneously variable, the surface damage of the rolled parts is effectively improved, and the possibility of core cracking is greatly reduced.

[0005] The technical solution adopted by the present application to solve the technical problems is:

[0006] A variable-angle cross wedge rolling die, the die comprising a wedge-in section, a widening section and a finishing section, the forming angle continuously changes along the wedge-in section to the widening section, and the widening angle continuously changes along the wedge-in section to the widening section.

[0007] Preferably, the structure for realizing the simultaneous continuous change of the forming angle and the widening angle is that the wedge-in section and the widening section have inclined side forming surfaces, the side forming surfaces continuously change along the width of the wedge-in section to the widening section, and the lower forming edge line of the side forming surface of the wedge-in section and the upper and lower two forming edge lines of the side forming surface of the widening section are curves.

[0008] Preferably, the forming angle gradually increases or gradually decreases along the wedge-in section to the widening section, and the widening angle gradually increases or gradually decreases along the wedge-in section to the widening section.

[0009] Preferably,

[0010] The structure that the forming angle gradually decreases along the wedge-in section to the widening section, and the widening angle gradually increases along the wedge-in section to the widening section is that the width of the side forming surface gradually increases along the wedge-in section to the widening section, and the lower forming edge line of the side forming surface of the wedge-in section and the upper and lower two forming edge lines of the side forming surface of the widening section are concave;

[0011] The structure that the forming angle gradually decreases along the wedge-in section to the widening section, and the widening angle gradually decreases along the wedge-in section to the widening section is that the width of the side forming surface gradually increases along the wedge-in section to the widening section, and the lower forming edge line of the side forming surface of the wedge-in section and the upper and lower two forming edge lines of the side forming surface of the widening section are convex;

[0012] The structure that the forming angle gradually increases along the wedge-in section to the widening section, and the widening angle gradually increases along the wedge-in section to the widening section is that the width of the side forming surface gradually decreases along the wedge-in section to the widening section, and the lower forming edge line of the side forming surface of the wedge-in section and the upper and lower two forming edge lines of the side forming surface of the widening section are concave;

[0013] The structure that the forming angle gradually increases along the wedge-in section to the widening section, and the widening angle gradually decreases along the wedge-in section to the widening section is that the width of the side forming surface gradually decreases along the wedge-in section to the widening section, and the lower forming edge line of the side forming surface of the wedge-in section and the upper and lower two forming edge lines of the side forming surface of the widening section are convex.

[0014] Preferably, the forming angle changes in the range of 20-45 degrees, and the widening angle changes in the range of 3-10 degrees.

[0015] Preferably, the upper and lower two edge lines of the side forming surface of the finishing section are straight lines and parallel.

[0016] Preferably, the lengths of the wedge-in section, the widening section and the finishing section are 85 mm, 225 mm and 55 mm respectively.

[0017] The beneficial effects of the present application are:

[0018] By using the wedge rolling die with variable forming angle and widening angle, according to the rotating condition and the core quality control requirement, the surface damage of the rolled piece can be improved, the possibility of core cracking of the rolled piece can be greatly reduced, and the process parameter selection window can be expanded; compared with the traditional roller, the variable widening angle (forming edge line concave) can save the die roller surface and reduce the cost. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is the planar development drawing of the rolling die of the present application, and the right side is a sectional view.

[0020] Figure 2 It is the planar development drawing of the rolling die of the embodiment 1 of the present application, and the right side is a sectional view.

[0021] Figure 3A planar development of a rolling die for the inventive example 2, right side is a cross-sectional view.

[0022] Figure 4 A planar development of a rolling die for the inventive example 3, right side is a cross-sectional view.

[0023] Figure 5 A planar development of a rolling die for the inventive example 4, right side is a cross-sectional view.

[0024] Figure 6 A planar development of a rolling die for the inventive example 4, right side is a cross-sectional view. DETAILED DESCRIPTION

[0025] The structure or technical terms used in the present application are further described below. These descriptions are only used to illustrate how the present application is implemented and cannot constitute any limitation on the present application.

[0026] As shown in Figures 1-5 A variable angle cross wedge rolling die, the die comprises a wedge-in section L1, a width-expanding section L2 and a finishing section L3, a forming angle a continuously changes along the wedge-in section L1 to the width-expanding section L2, and a width-expanding angle β continuously changes along the wedge-in section L1 to the width-expanding section L2. The change paths of the forming angle a and the width-expanding angle β start from the head end of the wedge-in section L1 and end at the tail end of the width-expanding section L2.

[0027] As a specific embodiment, the top surface of the wedge-in section L1 has a side forming surface, the top surface of the width-expanding section L2 is composed of a normal forming surface and side forming surfaces located on the left and right sides of the normal forming surface, the side forming surface of the wedge-in section L1 is smoothly connected with the side forming surface of the width-expanding section L2, the side forming surface is in an inclined shape, and the structure for realizing the continuous change of the forming angle and the width-expanding angle at the same time is that the side forming surface continuously changes along the width of the wedge-in section L1 to the width-expanding section L2, and the lower forming edge line of the side forming surface of the wedge-in section L1 and the upper and lower two forming edge lines of the side forming surface of the width-expanding section L2 are curves. The wedge-in section L1 only has a side forming surface 11, and the upper and lower two edge lines thereof are 111 and 112 respectively. The top surface of the width-expanding section L2 is composed of a normal forming surface 21 and side forming surfaces 22 located on the left and right sides of the normal forming surface 21, and the upper and lower two forming edge lines of the side forming surface 22 are 221 and 222 respectively. The width refers to the distance between the upper and lower two forming edge lines. The left and right side forming edge lines change at the same time and change identically.

[0028] As a specific example, the forming angle a gradually increases or gradually decreases along the wedge-in section L1 to the flare-out section L2, and the flare-out angle β gradually increases or gradually decreases along the wedge-in section L1 to the flare-out section L2. That is, when the forming angle a gradually increases along the wedge-in section L1 to the flare-out section L2, the flare-out angle β can be simultaneously increased or gradually decreased. Conversely, when the forming angle a gradually decreases along the wedge-in section L1 to the flare-out section L2, the flare-out angle β can be simultaneously decreased or gradually increased.

[0029] The relationship between the forming angle, the flare-out angle and the side forming surface is as follows:

[0030] In the structure of Example 1 in which the forming angle a gradually decreases along the wedge-in section L1 to the flare-out section L2, and the flare-out angle β gradually increases along the wedge-in section L1 to the flare-out section L2, the width of the side forming surface gradually increases along the wedge-in section L1 to the flare-out section L2, and the lower forming edge line of the side forming surface of the wedge-in section L1 and the upper and lower forming edge lines of the side forming surface of the flare-out section L2 are concave, as shown in FIG. 1. Figure 2 . Figure 2 The change of the forming angle a and the flare-out angle β along the wedge-in section L1 to the flare-out section L2 is shown in FIG. 2.

[0031] In the structure of Example 2 in which the forming angle a gradually decreases along the wedge-in section L1 to the flare-out section L2, and the flare-out angle β gradually decreases along the wedge-in section L1 to the flare-out section L2, the width of the side forming surface gradually increases along the wedge-in section L1 to the flare-out section L2, and the lower forming edge line of the side forming surface of the wedge-in section L1 and the upper and lower forming edge lines of the side forming surface of the flare-out section L2 are convex, as shown in FIG. 3. Figure 3 . Figure 3 The change of the forming angle a and the flare-out angle β along the wedge-in section L1 to the flare-out section L2 is shown in FIG. 4.

[0032] In the structure of Example 3 in which the forming angle a gradually increases along the wedge-in section L1 to the flare-out section L2, and the flare-out angle β gradually increases along the wedge-in section L1 to the flare-out section L2, the width of the side forming surface gradually decreases along the wedge-in section L1 to the flare-out section L2, and the lower forming edge line of the side forming surface of the wedge-in section L1 and the upper and lower forming edge lines of the side forming surface of the flare-out section L2 are concave, as shown in FIG. 5. Figure 4 . Figure 4 The change of the forming angle a and the flare-out angle β along the wedge-in section L1 to the flare-out section L2 is shown in FIG. 6.

[0033] In the structure of Example 4 in which the forming angle a gradually increases along the wedge-in section L1 to the flare-out section L2, and the flare-out angle β gradually decreases along the wedge-in section L1 to the flare-out section L2, the width of the side forming surface gradually decreases along the wedge-in section L1 to the flare-out section L2, and the lower forming edge line of the side forming surface of the wedge-in section L1 and the upper and lower forming edge lines of the side forming surface of the flare-out section L2 are convex, as shown in FIG. 7. Figure 5 . Figure 5The change of the forming angle a and the widening angle β along the direction from the wedge-in section L1 to the widening section L2 is shown.

[0034] As a specific embodiment, the forming angle a varies in the range of 20-45 degrees, and the widening angle β varies in the range of 3-10 degrees. The forming angle controls the size of the contact area between the tool and the workpiece. In these areas, a relatively small forming angle can increase the contact area, resulting in more localized plastic deformation, while the wedge exerts a small axial tension on the blank. An excessively large forming angle may cause material necking or breakage. A too small widening angle will result in a too small radial reduction, and an increase in the number of tension-compression cycles at the same location, which may result in greater core pressure. When the widening angle is too large, the spreading of the metal on the surface of the blank will be more difficult, resulting in a greater tension on the core of the blank and thus affecting the core quality.

[0035] As a specific embodiment, the top surface of the finishing section L3 is composed of a positive forming surface 31 and side forming surfaces 32 located on the left and right sides of the positive forming surface 31. The upper and lower edges 321, 332 of the side forming surfaces 32 are parallel and straight lines, and the forming angle a of the finishing section L3 is fixed.

[0036] As a specific embodiment, the lengths of the wedge-in section L1, the widening section L2, and the finishing section L3 are 85 mm, 225 mm, and 55 mm, respectively. The lengths of the sections of the die are not limited to the above and can be adjusted according to actual needs.

[0037] The traditional cross wedge rolling die includes a positive forming surface 41 and a side forming surface 42. The two forming edges 421, 422 of the side forming surface 42 are both parallel straight lines, as shown in Figure 6 The present application realizes variable a angle by changing the two forming edges of the side forming surface on the same side of the traditional die from the original parallel relationship to a non-planar relationship. The variable β angle is realized by changing the straight line widening of the left and right inclined planes of the side forming surface of the traditional die to curved widening (which can be convex or concave). By using the cross wedge rolling die with variable forming angle a and widening angle β, the surface damage of the rolled piece can be improved, and the possibility of cracking of the core of the rolled piece can be greatly reduced according to the rotation conditions and core quality control requirements. Compared with the traditional die, the variable β angle (the forming edge of the side forming surface is concave) saves the die roll surface and reduces the cost. The die can be applied to structures such as roller type and plate type.

[0038] The above only describes the preferred embodiments of the present application. It should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A variable angle cross wedge rolling die, the die comprising a wedge-in section, a spread section and a finishing section, characterized in that: the forming angle continuously changes along the wedge-in section to the spread section, while the spread angle continuously changes along the wedge-in section to the spread section; the structure for realizing the simultaneous continuous change of the forming angle and the spread angle is that the wedge-in section and the spread section have inclined side forming surfaces, the side forming surfaces continuously change along the width of the wedge-in section to the spread section, and the lower forming edge line of the side forming surface of the wedge-in section and the upper and lower two forming edge lines of the side forming surface of the spread section are curves; the forming angle gradually increases or gradually decreases along the wedge-in section to the spread section, and the spread angle gradually increases or gradually decreases along the wedge-in section to the spread section; the structure for making the forming angle gradually decrease along the wedge-in section to the spread section, while the spread angle gradually increase along the wedge-in section to the spread section is that the side forming surfaces gradually increase along the width of the wedge-in section to the spread section, and the lower forming edge line of the side forming surface of the wedge-in section and the upper and lower two forming edge lines of the side forming surface of the spread section are concave; the structure for making the forming angle gradually decrease along the wedge-in section to the spread section, while the spread angle gradually decrease along the wedge-in section to the spread section is that the side forming surfaces gradually increase along the width of the wedge-in section to the spread section, and the lower forming edge line of the side forming surface of the wedge-in section and the upper and lower two forming edge lines of the side forming surface of the spread section are convex; the structure for making the forming angle gradually increase along the wedge-in section to the spread section, while the spread angle gradually increase along the wedge-in section to the spread section is that the side forming surfaces gradually decrease along the width of the wedge-in section to the spread section, and the lower forming edge line of the side forming surface of the wedge-in section and the upper and lower two forming edge lines of the side forming surface of the spread section are concave; the structure for making the forming angle gradually increase along the wedge-in section to the spread section, while the spread angle gradually decrease along the wedge-in section to the spread section is that the side forming surfaces gradually decrease along the width of the wedge-in section to the spread section, and the lower forming edge line of the side forming surface of the wedge-in section and the upper and lower two forming edge lines of the side forming surface of the spread section are convex. The forming angle changes in the range of 20-45 degrees, and the spread angle changes in the range of 3-10 degrees. The upper and lower two edge lines of the side forming surface of the finishing section are straight lines and parallel. The lengths of the wedge-in section, the spread section and the finishing section are 85 mm, 225 mm and 55 mm respectively. ​ ​ ​ 2. A variable angle cross wedge rolling die as claimed in claim 1, characterized in that: ​ 3. A variable angle cross wedge rolling die as defined in claim 1 wherein: ​ 4. A variable angle cross wedge rolling die as defined in claim 1 wherein: ​

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