Method for drawing a long round section bar from a die
By using a three-pass 90° rotation elongation method, the mating distance between the upper and lower anvils is equal in each pass, which solves the problem of low elongation efficiency of traditional anvils, improves elongation efficiency and forming quality, and reduces surface cracking.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA NAT ERZHONG GRP DEYANG WANHANG DIE FORGING CO LTD
- Filing Date
- 2023-02-10
- Publication Date
- 2026-05-12
AI Technical Summary
Traditional anvil drawing methods are inefficient, resulting in insufficient temperature during the later stages of billet deformation, poor material plasticity, and defects such as surface cracking.
A three-pass 90° rotation elongation method is adopted, with equal mating distances between the upper and lower anvils in each pass. The mating distance is determined through software simulation or on-site experiments. V-shaped or arc-shaped anvils are used for elongation to ensure that the mating distance in each pass is equal to the theoretical elongation circular cross-sectional area.
It improves drawing efficiency, ensures that the billet maintains a high temperature during the drawing process, improves the drawing and forming quality, and reduces the risk of surface cracking.
Smart Images
Figure CN116037832B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of drawing technology, and specifically to a method for drawing long round cross-section bars using an anvil. Background Technology
[0002] Lengthening is a free forging deformation method that reduces the cross-section of a billet and increases its length. It is widely used because it can change the shape of the billet, improve the distribution of inclusions, and forge internal pore defects in the material. Traditional anvil lengthening involves setting the distance between the upper and lower anvils, rotating the billet 90°, and then repeatedly adjusting it to a perfect circle at small angles of 30° / 45°. This method has a long length of time and low efficiency, resulting in insufficient temperature in the later stages of billet deformation, poor material plasticity, and defects such as severe surface cracking. Summary of the Invention
[0003] The technical problem to be solved by the present invention is to provide a method for drawing long circular cross-section bars using an anvil that can improve the efficiency of circular cross-section bars.
[0004] The technical solution adopted by this invention to solve its technical problem is: a method for drawing long cylindrical cross-section bars from an anvil, the method comprising:
[0005] The circular cross-section bar is placed between the upper and lower anvils and drawn in three passes, with each pass rotating 90° between passes, wherein the mating distance between the upper and lower anvils is equal in each pass, so as to obtain an equivalent drawn part with a cross-sectional area equal to the area of the theoretically drawn circular cross-section of the circular cross-section bar.
[0006] Furthermore, the mating distance between the upper and lower anvils in each pass is determined in the following way:
[0007] The software simulation determined the relationship curve between the mating distance between the upper and lower anvils and the diameter of the equivalent drawn circular cross-section, which is equal to the cross-sectional area of the formed equivalent drawn part, when the circular cross-section bar is drawn using the upper and lower anvils in three passes, with each pass rotating 90°, wherein the mating distance between the upper and lower anvils is equal in each pass.
[0008] Find the point on the relationship curve where the diameter of the equivalent elongated circular cross section is equal to the theoretical elongated circular cross section diameter of the circular cross section bar. The mating distance between the upper and lower anvils corresponding to this point is the mating distance between the upper and lower anvils in each elongation pass.
[0009] Furthermore, the relationship curve was obtained by simulation using deform software.
[0010] Furthermore, both the upper and lower anvils are V-shaped anvils.
[0011] The beneficial effects of the present invention are: the method of drawing long round cross-section bars with an anvil of the present invention reduces the number of drawing passes, and the matching distance between the upper anvil and the lower anvil in each pass is equal, which facilitates operation. Therefore, the drawing efficiency is higher, and it can better ensure that the billet is at a higher temperature during drawing, which is conducive to its drawing deformation and can improve the quality of drawing and forming. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of the process for drawing round cross-section bars according to the present invention;
[0013] Figure 2 It is a curve showing the relationship between the mating distance between the upper and lower anvils and the diameter of the equivalent elongated circular cross section;
[0014] Figure label:
[0015] Circular cross-section bar stock 1, upper anvil 2, lower anvil 3, equivalent drawing part 4, first intermediate blank 11, second intermediate blank 12. Detailed Implementation
[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0017] like Figure 1 As shown, the present invention discloses a method for drawing long cylindrical cross-section bars from an anvil, the method comprising:
[0018] The circular cross-section bar 1 is placed between the upper anvil 2 and the lower anvil 3, and is drawn in three passes, with each pass rotating 90°. The mating distance between the upper anvil 2 and the lower anvil 3 is equal in each pass, and the drawing is done in the manner of H, so as to obtain an equivalent drawing piece 4 with a cross-sectional area that is equivalent to the area of the theoretically drawn circular cross-section of the circular cross-section bar.
[0019] In this invention, the lengthening process in one pass refers to placing the bar stock between the upper anvil 2 and the lower anvil 3, without rotating the bar stock around its axis, and then using the upper anvil 2 and the lower anvil 3 to squeeze and lengthen the bar stock from one end to the other end.
[0020] Combination such as Figure 1 The method of the present invention will be described in detail below:
[0021] First, place the circular cross-section bar stock 1 between the upper anvil 2 and the lower anvil 3, with a mating distance of H between the upper anvil 2 and the lower anvil 3, without rotating the bar stock around its axis. Then, use the upper anvil 2 and the lower anvil 3 to extrude and draw the circular cross-section bar stock 1 from one end to the other end, extruding the circular cross-section bar stock 1 in one pass to obtain the first intermediate billet 11.
[0022] The first intermediate billet 11 is then rotated 90° around its axis and placed between the upper anvil 2 and the lower anvil 3. The mating distance between the upper anvil 2 and the lower anvil 3 remains H. Without rotating the bar stock (first intermediate billet 11) around its axis, the upper anvil 2 and the lower anvil 3 are used to extrude and stretch the bar stock (first intermediate billet 11) from one end to the other end to complete the second extrusion pass and obtain the second intermediate billet 12.
[0023] Finally, the second intermediate blank 12 is rotated 90° around its axis and placed between the upper anvil 2 and the lower anvil 3. The mating distance between the upper anvil 2 and the lower anvil 3 is still H. Without rotating the bar stock (second intermediate blank 12) around its axis, the upper anvil 2 and the lower anvil 3 are used to extrude and draw the bar stock (second intermediate blank 12) from one end to the other end, thus completing the third extrusion pass, so as to obtain an equivalent drawing part 4 with a cross-sectional area that is equivalent to the area of the theoretically drawn circular cross-section of the circular cross-section bar stock.
[0024] The conventional drawing method, which involves 90° rotation deformation followed by repeated small-angle trimming at 30° / 45° to achieve a perfect circle, slows down the length increase rate with each drawing pass, with the fastest growth rate in the first three passes. This is because in the later stages of drawing, the distance between the upper and lower anvils decreases, the deformation decreases, and the length increase along the length direction becomes smaller. While the existing method can make the cross-section of the formed drawn part closer to the theoretical circular cross-section, it results in a long drawing time and low efficiency. This invention uses a three-pass drawing method, with a 90° rotation between each pass. In each pass, the mating distance between the upper anvil 2 and the lower anvil 3 is equal, resulting in a drawn part 4 with a cross-sectional area equivalent to the theoretically drawn circular cross-section of a circular bar. This reduces the number of drawing passes, and the equal mating distance between the upper anvil 2 and the lower anvil 3 in each pass facilitates operation. Therefore, the drawing efficiency is higher, and it better ensures that the billet is at a higher temperature during drawing, which is beneficial for its drawing deformation and improves the quality of the drawn part. Since the cross-sectional area of the formed equivalent elongated part 4 is equal to the area of the theoretically elongated circular cross-section of the circular cross-section bar, this method has virtually no adverse effect on the subsequent die forging of the elongated part.
[0025] In some embodiments, the mating distance between the upper anvil 2 and the lower anvil 3 in each pass is also determined by field experiments.
[0026] In this invention, the mating distance between the upper anvil 2 and the lower anvil 3 in each pass is determined in the following manner:
[0027] The software simulation was used to determine the relationship curve between the engagement distance between the upper anvil 2 and the lower anvil 3 and the diameter of the equivalent drawn circular cross section, which is equal to the cross-sectional area of the formed equivalent drawn part 4, when the circular cross section bar 1 is drawn using the upper anvil 2 and the lower anvil 3 in three passes, with each pass rotating 90°, wherein the engagement distance between the upper anvil 2 and the lower anvil 3 is equal in each pass.
[0028] Find the point on the relationship curve where the diameter of the equivalent elongated circular cross section is equal to the theoretical elongated circular cross section diameter of the circular cross section bar 1. The matching distance between the upper anvil 2 and the lower anvil 3 corresponding to this point is the matching distance between the upper anvil 2 and the lower anvil 3 in each elongation pass.
[0029] Specifically, the Deform software can be used to simulate and obtain the relationship curve between the engagement distance between the upper anvil 2 and the lower anvil 3 and the diameter of the equivalent elongated circular cross-section, which is equal to the cross-sectional area of the formed equivalent elongated part 4, when the circular cross-section bar 1 is elongated by the upper anvil 2 and the lower anvil 3 in three passes, with each pass rotating 90°, wherein the engagement distance between the upper anvil 2 and the lower anvil 3 is equal in each pass.
[0030] In some embodiments, the mating distance between the upper anvil 2 and the lower anvil 3 in each pass is also determined by field experiments.
[0031] The upper anvil 2 and lower anvil 3 of the present invention can be V-shaped anvils or arc-shaped anvils, etc.
[0032] Example
[0033] The upper anvil 2 and the lower anvil 3 adopt V-shaped anvils with an opening angle of 120° and a top fillet radius of R165mm; the closed height is 155mm, that is, the minimum diameter of the drawn circle is φ155mm; to ensure a smooth transition of the billet, the edge of the "V" shaped anvil is beveled at 75×45°. The specifications of the round section bar 1 are: φ300×500mm, the material is TA15 titanium alloy, and the theoretical drawn section of the round section bar 1 is φ200mm.
[0034] Step 1: Using Deform software, establish models of the aforementioned circular cross-section bar stock, upper anvil, and lower anvil. Simulate the process using Deform software to obtain the relationship curve between the mating distance between upper anvil 2 and lower anvil 3 and the diameter of the equivalent drawn circular cross-section (where the cross-sectional area equals the cross-sectional area of the formed equivalent drawn part 4) when the circular cross-section bar stock is drawn using the upper and lower anvils in three passes, with each pass involving a 90° rotation. (See the diagram.) Figure 2 ;
[0035] Step two: Based on the relationship curve, find the point where the diameter of the equivalent drawn circular section is equal to the theoretical drawn circular section diameter of the circular section bar 1, i.e., the point where the diameter of the equivalent drawn circular section is equal to φ200mm. The mating distance between the upper anvil 2 and the lower anvil 3 corresponding to this point is the mating distance between the upper anvil 2 and the lower anvil 3 in each drawing pass. Figure 2 From this, it can be concluded that when the diameter of the equivalent elongated circle is equal to φ200mm, the mating distance between the upper anvil 2 and the lower anvil 3 at this point is 32mm.
[0036] Step 3: Place the circular cross-section bar between the upper and lower anvils and elongate it in three passes, rotating 90° between each pass, with a mating distance of 32mm between the upper and lower anvils in each pass, to obtain an equivalent elongated part 4 with a cross-sectional area equal to the theoretical elongated circular cross-sectional area of the circular cross-section bar 1.
Claims
1. A method for drawing long cylindrical cross-section bars from an anvil, characterized in that, The method includes: The circular cross-section bar (1) is placed between the upper anvil (2) and the lower anvil (3) and drawn in three passes, rotating 90° between each pass, wherein the mating distance between the upper anvil (2) and the lower anvil (3) is equal in each pass, so as to obtain an equivalent drawn part (4) with a cross-sectional area equal to the area of the theoretical drawn circular cross-section of the circular cross-section bar (1); the mating distance between the upper anvil (2) and the lower anvil (3) in each pass is determined in the following way: The software simulation was used to determine the relationship curve between the engagement distance between the upper anvil (2) and the lower anvil (3) and the diameter of the equivalent elongated circular cross section whose cross-sectional area is equal to the cross-sectional area of the formed equivalent elongated part (4) when the circular cross section bar (1) is elongated by the upper anvil (2) and the lower anvil (3) in three passes, with each pass rotating 90°, wherein the engagement distance between the upper anvil (2) and the lower anvil (3) in each pass is equal. Find the point on the relationship curve where the diameter of the equivalent elongated circular cross section is equal to the theoretical elongated circular cross section diameter of the circular cross section bar (1). The matching distance between the upper anvil (2) and the lower anvil (3) corresponding to this point is the matching distance between the upper anvil (2) and the lower anvil (3) in each elongation pass.
2. The method for drawing elongated cylindrical cross-section bars from an anvil as described in claim 1, characterized in that, The relationship curves were obtained through simulation using Deform software.
3. The method for drawing elongated cylindrical cross-section bars from an anvil as described in claim 1, characterized in that, Both the upper anvil (2) and the lower anvil (3) are V-shaped anvils.