A bevel drawing anvil and a drawing method for improving the uniformity of a drawing process

Abstract

The present application mainly relates to a bevel elongation anvil for improving the deformation uniformity of an elongation process and an elongation method thereof. The anvil comprises an upper anvil and a lower anvil arranged in axial symmetry and opposite to each other. A contact surface in contact with a blank is arranged on the side of the upper anvil and the lower anvil close to the blank. Symmetrical bevel transition structures with the same structure are arranged at the two ends of the contact surface. There is a bevel angle between the bevel of the bevel transition structure and the plane of the contact surface. The elongation method for improving the deformation uniformity of the elongation process by using the bevel elongation anvil comprises the following steps: step 1: using the bevel elongation anvil to perform first-stage elongation processing on the blank to complete 30%-40% of the total deformation amount of the reduction; and step 2: using the bevel elongation anvil to perform second-stage elongation processing on the blank to continue to complete the deformation of the remaining part of the reduction amount of the total deformation amount of the reduction. The elongation anvil with the bevel transition structure and the semi-pre-pressing method are used to reduce the difficult deformation area, which can significantly reduce the size of the accumulated deformation bulge of the effective use area of the blank.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of plastic forming of metal materials, and particularly relates to a bevel elongation anvil for improving deformation uniformity of an elongation process and an elongation method thereof. BACKGROUND

[0002] In a forging process, free forging has the characteristics of high universality and low cost, and is widely used in blanking of a blank. At present, enterprises widely adopt traditional asymmetric, single-sided and one-way free forging elongation with a narrow anvil on top and a wide anvil on bottom. In each pass of the elongation process, the blank only undergoes single-sided cumulative deformation. After the blank is turned over, although the same reduction is used for elongation, the difference in height size before each pass of elongation will cause a difference in deformation between the upper and lower surfaces of the blank. The cumulative deformation of the multi-pass elongation process will make the overall deformation of the blank uneven, resulting in a difference in mechanical properties such as strength and toughness of the blank at different positions and detection failure. In addition, the traditional elongation process also uses an upper and lower flat anvil structure without a bevel, which will generate a large difficult-to-deform area during the elongation of the blank and increase the cumulative deformation bulging size, as shown in FIG. 1, thereby reducing the deformation uniformity of the effective use area of the blank. Figure 4 SUMMARY

[0003] In view of the deficiencies of the prior art, the present application provides a bevel elongation anvil for improving deformation uniformity of an elongation process and an elongation method thereof, which can effectively control the overall deformation unevenness caused by uneven deformation of the upper and lower surfaces of the blank after elongation.

[0004] The bevel elongation anvil for improving deformation uniformity of an elongation process provided by the present application comprises an upper anvil and a lower anvil arranged in axial symmetry and opposite to each other. The upper anvil and the lower anvil have the same structure, and the longitudinal central axes of the upper anvil and the lower anvil coincide. A contact surface in contact with the blank is arranged on the side of the upper anvil close to the blank. Symmetrically arranged at the two ends of the contact surface are bevel transition structures with the same structure. The bevel of the bevel transition structure is arranged in the moving direction of the blank. The edge of the bevel close to the blank is connected with the contact surface. The other edge of the bevel is away from the plane where the contact surface is located, so that there is a bevel included angle between the bevel and the plane where the contact surface is located.

[0005] Preferably, the height of the bevel is greater than one half of the value of the elongation reduction, and the width of the contact surface in the moving direction of the blank is greater than the value of the elongation feed.

[0006] Preferably, the bevel included angle is in the range of 20° to 50°, the height of the bevel is in the range of 20mm to 100mm, and the width of the contact surface in the moving direction of the blank is in the range of 100mm to 300mm. ​

[0007] A method for improving the deformation uniformity of elongation process by using a bevel elongation anvil, comprising the following steps:

[0008] Step 1: using a bevel elongation anvil to perform first-stage elongation processing on the blank, and the blank is deformed by the first-stage reduction amount; the value of the first-stage reduction amount is between 30% and 40% of the total reduction deformation value of the blank after the first-stage elongation processing and the second-stage elongation processing.

[0009] Step 2: using a bevel elongation anvil to perform second-stage elongation processing on the blank, and the blank is deformed by the remaining part of the total reduction deformation value.

[0010] Preferably, step 1 comprises the following steps:

[0011] Step 11: placing the heated blank in the middle region between the upper anvil and the lower anvil, and the central axis of the blank coincides with the longitudinal central axis of the upper anvil;

[0012] Step 12: controlling the press to drive the upper anvil to move downward to 50% of the first set single reduction amount, and completing the semi-pre-pressing; the value of the first-stage reduction amount is an even multiple of the value of the first set single reduction amount.

[0013] Step 13: controlling the blank to feed to the first feeding end by a set feeding amount, and the value of the set feeding amount is smaller than the width of the contact surface along the moving direction of the blank, and controlling the press to drive the upper anvil to move downward to the first set single reduction amount at the same time, until the blank completes the elongation in the direction of the first feeding end.

[0014] Step 14: controlling the blank to feed to the second feeding end according to the elongation method of step 13 to perform the same elongation operation, until the blank completes the elongation in the direction of the second feeding end; the direction of the second feeding end is opposite to the direction of the first feeding end.

[0015] Step 15: changing the feeding sequence of the blank to the two feeding ends, and re-performing the elongation processing operation on the blank according to the elongation processing method of steps 11 to 14.

[0016] Step 16: repeating the cyclic elongation processing operation on the blank according to the elongation processing method of steps 11 to 15, until the value of the cumulative reduction deformation of the blank reaches the value of the first-stage reduction amount.

[0017] Preferably, step 2 comprises the following steps:

[0018] Step 21: placing the end part of the blank at one end in the middle region between the upper anvil and the lower anvil.

[0019] Step 22: controlling the press to drive the upper anvil to move downward to the second set single reduction amount, and completing the single reduction deformation.

[0020] Step 23: control the blank to feed to the other end of the blank in the direction of the set feed amount, control the press to drive the upper anvil to move downward to the second set single stroke amount, until the blank completes the first pass of the elongation processing operation;

[0021] Step 24: change the feeding direction of the blank, and perform elongation processing operation on the blank according to the elongation processing method of steps 21 to 23;

[0022] Step 25: repeat the reciprocating elongation processing operation on the blank according to the elongation processing method of steps 21 to 24, until the remaining part of the total deformation amount of the stroke is deformed.

[0023] The present application provides a bevel type elongation anvil and a symmetrical elongation method thereof, which reduces the difficult deformation area by using an elongation anvil with a bevel transition structure and a semi-pressing method, and also significantly reduces the cumulative deformation bulge size of the effective use area of the blank, as shown in Figure 5 Thus, the overall deformation unevenness caused by the uneven deformation of the upper and lower surfaces can be effectively controlled. In the elongation process, the first stage is elongated from the middle to both ends, and the first pass is semi-pressing, which increases the deformation amount of the difficult deformation area and reduces the double bulge at both ends; the second stage is bidirectional cyclic feeding elongation from both ends, which improves the elongation efficiency. This method can reduce the temperature loss caused by blank turning and unidirectional feeding, reduce the forming process fire times and improve the production efficiency, realize the free forging elongation forming of the overall deformation uniformization of the blank. Compared with the traditional method, the component of the feeding direction will be larger, which promotes the deformation of the blank in the feeding direction, thereby improving the unidirectional strain in the feeding direction, and further improving the unidirectional deformation uniformity, which can achieve better elongation effect in the elongation processing technology of long axis and long plate. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a schematic diagram of the bevel type elongation anvil structure of the embodiment of the present application;

[0025] Figure 2 It is a schematic diagram of the first stage forming process of the symmetrical elongation of the embodiment of the present application;

[0026] Figure 3 It is a schematic diagram of the second stage forming process of the symmetrical elongation of the embodiment of the present application;

[0027] Figure 4 It is a metal flow line diagram of the blank in the center layer section in the thickness direction using the traditional elongation forming;

[0028] Figure 5 It is a metal flow line diagram of the blank in the center layer section in the thickness direction using the bevel type elongation anvil structure and the symmetrical elongation method of the embodiment of the present application;

[0029] Figure 1 Fig. 1 is a schematic view of the inclined surface elongation anvil, wherein 1 is an upper anvil, 2 is a blank, 3 is a lower anvil, 4 is a contact surface, 5 is an inclined surface, H is the height of the inclined surface, W is the width of the contact surface along the moving direction of the blank, and a is the angle of the inclined surface. DETAILED DESCRIPTION

[0030] The present application provides an inclined surface elongation anvil for improving the deformation uniformity of the elongation process, which comprises an upper anvil 1 and a lower anvil 3 arranged in axial symmetry and opposite to each other, wherein the upper anvil 1 and the lower anvil 3 have the same structure, and the longitudinal central axis of the upper anvil 1 coincides with that of the lower anvil 3; the upper anvil 1 is provided with a contact surface 4 on the side close to the blank 2, which is in contact with the blank 2; the two ends of the contact surface 4 are symmetrically provided with inclined surface transition structures with the same structure; the inclined surface 5 of the inclined surface transition structure is arranged in the inclined direction along the moving direction of the blank 2; the edge of the inclined surface 5 close to the blank 2 is connected with the contact surface 4; the other edge of the inclined surface 5 is away from the plane where the contact surface 4 is located, so that there is an angle a between the inclined surface 5 and the plane where the contact surface 4 is located; the length of the upper anvil 1 and the lower anvil 3 is less than the length of the working table of the press, and the symmetric elongation forming load must be less than the nominal pressure of the press; the value range of the height H of the inclined surface is greater than one half of the value of the elongation reduction, and is between 20 mm and 100 mm; the value range of the width W of the contact surface along the moving direction of the blank is greater than the value of the elongation feed, and is between 100 mm and 300 mm; and the value range of the angle a of the inclined surface is between 20° and 50°.

[0031] The present application will be further described below in conjunction with the drawings and examples. It should be understood that the specific embodiments presented herein are only used to explain the present application but not to limit the present application.

[0032] Examples

[0033] As Figure 1As shown, the embodiment relates to a bevel elongation anvil including a bevel transition structure, including an upper anvil 1 and a lower anvil 3 with the same structure, and the working area length of the upper anvil 1 and the lower anvil 3 is 2500 mm, wherein the width W of the contact surface of the upper anvil 1 and the lower anvil 3 along the moving direction of the blank is 210 mm, the bevel height H is 80 mm, and the bevel angle α is 30°. In this embodiment, the value of the bevel angle α, the value of the bevel height H and the value of the width W of the contact surface along the moving direction of the blank of the bevel elongation anvil are determined according to the thickness of the blank 2 and the number of heading before the blank 2 is elongated. If the number of heading before the blank 2 is elongated is small, the blank 2 is thin, a small angle value can be combined with a large width value and a small height value; if the number of heading before the blank 2 is elongated is large, the blank 2 is thick, a large angle value can be combined with a small width value and a large height value. Among them, the value of the bevel height H and the value of the width W of the contact surface along the moving direction of the blank of the bevel elongation anvil are determined after the set feed value and the first set single reduction amount are determined according to the condition of the blank 2, which is generally slightly larger than the value of the set feed value and the value of the first set single reduction amount. In order to effectively reduce the elongation processing cost, the value of the bevel height H and the value of the width W of the contact surface along the moving direction of the blank of a set of bevel elongation anvil can be designed to be larger in actual operation, and the value of the bevel angle α is also set to be close to the middle value of the value range, so that the elongation anvil can be used for elongation processing operation of various blanks 2, and the universality is higher.

[0034] As shown in Figure 2 and Figure 3 The embodiment relates to a bevel elongation method for improving the deformation uniformity of the elongation process by using a bevel elongation anvil including a bevel transition structure, including the following steps:

[0035] Step 1: using a bevel elongation anvil to perform first-stage elongation processing on an aluminum alloy blank 2, so that the aluminum alloy blank 2 completes the deformation of the first-stage reduction amount; the value of the first-stage reduction amount is between 30% and 40% of the total reduction deformation value of the blank 2 after the first-stage elongation processing and the second-stage elongation processing. In this embodiment, the total elongation reduction deformation is set to 430 mm, and the first-stage reduction amount is 160 mm. The specific elongation process of the first stage includes the following steps:

[0036] Step 11: placing the heated blank 2 in the middle area of the upper anvil 1 and the lower anvil 3, and the central axis of the blank 2 coincides with the longitudinal central axis of the upper anvil 1;

[0037] Step 12: control the press to drive the upper anvil 1 to move downward to 50% of the first set single stroke amount, i.e. 40mm, to complete the semi-pre-pressing. The value of the first stage stroke amount is an even multiple of the value of the first set single stroke amount, and in this embodiment, the first stage stroke amount 160mm is 2 times the first set single stroke amount 80mm;

[0038] Step 13: control the blank 2 to feed to the first feeding end by the set feeding amount 170mm, and control the press to drive the upper anvil 1 to move downward to the first set single stroke amount 80mm at the same time, until the blank 2 completes the elongation in the first feeding end direction;

[0039] Step 14: control the blank 2 to feed to the second feeding end according to the elongation method in step 13 to perform the same elongation operation, until the blank 2 completes the elongation in the second feeding end direction, which is the opposite direction of the first feeding end direction. In this step, there are two methods when performing the elongation operation from the feeding end that has completed the elongation operation to the opposite direction feeding end: the first method is to directly perform the elongation operation from the feeding end that has completed the elongation operation to the opposite direction feeding end until the blank 2 completes the elongation operation of the first set single stroke amount once; the second method is to perform the elongation operation from the central axis of the blank 2 to the opposite direction feeding end until the blank 2 completes the elongation operation of the first set single stroke amount once. The two methods are determined according to the difficulty of adjusting the position of the blank 2 during the actual elongation operation, but only one method can be used fixedly in the complete elongation operation of the same blank 2, and the two methods cannot be mixed for operation.

[0040] Step 15: change the feeding sequence of the blank 2 to the two feeding ends, and perform the elongation operation on the blank 2 according to the elongation operation method in steps 11 to 14 again, and finally the cumulative stroke deformation value of the blank 2 reaches the value of the first stage stroke amount 160mm.

[0041] Step 2: perform the second stage elongation operation on the aluminum alloy blank 2 by using the inclined elongation anvil, and continue to elongate the aluminum alloy blank 2 to complete the remaining elongation stroke 270mm of the total stroke deformation. The second stage specific elongation process includes the following steps:

[0042] Step 21: place the end part of the aluminum alloy blank 2 in the middle area between the upper anvil 1 and the lower anvil 3;

[0043] Step 22: control the press to drive the upper anvil 1 to move downward to the second set single stroke amount 80mm to complete the stroke deformation, and in this embodiment, the value of the second set single stroke amount is determined according to the comprehensive data of the uniformity required during the deformation of the aluminum alloy blank 2 and the process efficiency in this embodiment;

[0044] Step 23: Control the aluminum alloy billet 2 to feed towards the other end of the billet 2 at the set feed amount of 170mm, and control the press to drive the upper anvil 1 downward to the second set single pressing amount of 80mm, until the billet 2 completes one round of drawing operation.

[0045] Step 24: Change the feed direction of aluminum alloy billet 2 and perform the drawing operation on billet 2 according to the drawing operation method in steps 21 to 23.

[0046] Step 25: Repeat the elongation process of steps 21 to 24 to perform a reciprocating elongation process on the aluminum alloy billet 2 until the remaining part of the total deformation is completed.

[0047] like Figure 4 As shown, if the blank 2 formed by the traditional drawing method is used, a large bulge will form in the middle effective use area, with a size of about 47mm. In addition, the difference in the cumulative deformation of the upper and lower parts leads to the overall uneven deformation of the effective use area.

[0048] like Figure 5 As shown, the billet 2 formed by the drawing method of the present invention, which uses a drawing anvil with a slope transition structure to improve the deformation uniformity of free forging drawing process, has a small bulge in the middle effective use area, with a size of about 8 mm. This indicates that the problem of deformation non-uniformity caused by non-uniform deformation rate has been effectively improved.

[0049] The symmetrical drawing method described in this invention allows for the design and use of different reduction and feed rates based on the initial size of the billet and the forging dimensions, achieving uniform free forging of billets of different sizes. The contact surface width and bevel height of the inclined drawing anvil described in this invention can be increased within a limited range according to the actual reduction requirements during forming, and the contact surface width can be increased according to the feed requirements, thus more flexibly adapting to the free forging drawing process.

[0050] The above embodiments are merely illustrative examples to clearly illustrate the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method of improving the uniformity of deformation in a stretch process using a bevel stretch-die to lift the stretch process, characterized by, The inclined elongation anvil comprises an upper anvil and a lower anvil arranged in axial symmetry, the upper anvil and the lower anvil have the same structure, and the longitudinal central axis of the upper anvil coincides with that of the lower anvil; the upper anvil is provided with a contact surface in contact with the blank on the side close to the blank, and the two ends of the contact surface are symmetrically provided with inclined transition structures with the same structure, the inclined direction of the inclined surface is arranged along the moving direction of the blank, the edge of the inclined surface close to the blank is connected with the contact surface, and the other edge of the inclined surface is away from the plane where the contact surface is located, so that there is an inclined angle between the inclined surface and the plane where the contact surface is located; the height of the inclined surface is greater than half of the elongation reduction amount, the width of the contact surface along the moving direction of the blank is greater than the elongation feed amount; the value of the inclined angle is between 20° and 50°, the value of the height of the inclined surface is between 20mm and 100mm, and the value of the width of the contact surface along the moving direction of the blank is between 100mm and 300mm; The elongation method using the inclined elongation anvil to improve the deformation uniformity of the elongation process comprises the following steps: Step 1: using the inclined elongation anvil to perform first-stage elongation processing on the blank, and completing the deformation of the first-stage reduction amount of the elongated blank; the value of the first-stage reduction amount is between 30% and 40% of the total reduction deformation value of the blank after the first-stage elongation processing and the second-stage elongation processing; Step 1: elongating from the middle to the two ends, comprising the following steps: Step 11: placing the heated blank in the middle area of the upper anvil and the lower anvil, and the central axis of the blank coincides with the longitudinal central axis of the upper anvil; Step 12: controlling the press to drive the upper anvil to move downward to 50% of the first set single reduction amount, and completing the semi-pre-pressing; the value of the first-stage reduction amount is an even multiple of the value of the first set single reduction amount; Step 13: controlling the blank to feed to the first feeding end at a set feed amount, the value of the set feed amount is less than the width of the contact surface along the moving direction of the blank, and controlling the press to drive the upper anvil to move downward to the first set single reduction amount at the same time, until the blank completes the elongation in the first feeding end direction; Step 14: controlling the blank to feed to the second feeding end according to the elongation method of step 13 to perform the same elongation operation, until the blank completes the elongation in the second feeding end direction; the second feeding end direction is the opposite direction of the first feeding end direction; Step 15: changing the feeding sequence of the blank to the two feeding ends, and re-performing the elongation processing operation on the blank according to the elongation processing method of steps 11 to 14; Step 16: repeatedly performing the cyclic elongation processing operation on the blank according to the elongation processing method of steps 11 to 15, until the value of the cumulative reduction deformation of the blank reaches the value of the first-stage reduction amount; Step 2: using the inclined elongation anvil to perform second-stage elongation processing on the blank, and continuing to elongate the blank to complete the deformation of the remaining part of the total reduction deformation amount.

2. A method of elongating according to claim 1, wherein the method is characterized by, Step 2: comprising the following steps: Step 21: placing the end part of the blank in the middle area of the upper anvil and the lower anvil; Step 22: control the press to drive the upper anvil to move downward to a second set single reduction amount, complete a single reduction deformation; Step 23: control the blank to feed to the other end of the blank according to the set feeding amount, and control the press to drive the upper anvil to move downward to the second set single reduction amount at the same time, until the blank completes a drawing operation in one pass; Step 24: change the feeding direction of the blank, and perform the drawing operation on the blank according to the drawing method of steps 21 to 23; Step 25: repeat the drawing operation on the blank according to the drawing method of steps 21 to 24 in a reciprocating cycle until the remaining part of the total reduction amount is deformed.

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