Cold drawing finishing device and process

Abstract

The present invention discloses a cold drawing finishing device and process, which comprises a die base, an outer die is fixedly installed inside the die base; and an inner die is fixedly installed on a pull rod, and the pull rod is fixedly connected to a fixed core rod; the inner die and the outer die are used in pairs, and the distance between the inner die and the outer die is ≥10mm. This finishing device can perform cold drawing finishing again on products with excessive dimensional accuracy produced during the cold drawing production process to achieve the required dimensional accuracy, and then transform them into qualified products, thereby achieving the purpose of saving resources and effectively reducing costs.

Description

Technical Field

[0001] The invention belongs to the field of cold-drawn tube finishing devices, and in particular relates to a cold-drawn finishing device and process. Background Art

[0002] Due to the high hardness of high-strength quenched and tempered tubes, the base hardness is usually greater than 250HB. During the cold drawing process using inner and outer dies to reduce the wall, the inner hole size accuracy generally cannot meet the requirements. At the same time, the cold drawing die loss of high-strength tubes is large.

[0003] At present, according to preliminary statistics, in the field of cold drawing of high-strength quenched and tempered precision steel tubes, defective products due to excessive tolerance of inner hole size accuracy account for about 5%. For a cold drawing enterprise with an annual output of about 30,000 tons, about 1,500 tons of products have excessive tolerance of accuracy every year. Summary of the invention

[0004] The purpose of the present invention is to provide a cold drawing finishing device and process, which can perform cold drawing finishing on products with dimensional accuracy exceeding the tolerance produced in the cold drawing production process again to achieve the required dimensional accuracy and then transform them into qualified products, thereby achieving the purpose of saving resources and effectively reducing costs.

[0005] In order to realize the above technical features, the object of the present invention is achieved as follows: a cold drawing finishing device, which includes a die base, and an outer die is fixedly installed inside the die base;

[0006] It also includes an inner mold, which is fixedly mounted on a pull rod, and the pull rod is fixedly connected to a fixed core rod;

[0007] The inner mold and the outer mold are used in pairs, and the distance between the inner mold and the outer mold is ≥10mm.

[0008] The pull rod includes a pull rod head, and the pull rod head is fixedly connected to the mounting sleeve of the fixed core rod head. The other end of the pull rod head is a spacer sleeve shaft section, and the spacer sleeve shaft section is mounted on the spacer sleeve shaft section. The other end of the spacer sleeve shaft section is an inner mold shaft section, and the inner mold shaft section is mounted on the inner mold shaft section. The inner mold is mounted on the inner mold shaft section, and the other end of the inner mold shaft section is a threaded shaft section, and a locking nut for limiting the inner mold end head is installed on the threaded shaft section.

[0009] The end of the threaded shaft section is provided with a hexagonal head.

[0010] The inner diameter of the outer die is 1-4 mm smaller than the outer diameter of the tube blank.

[0011] The outer diameter of the inner mold is 0-2 mm larger than the required inner diameter of the finished product.

[0012] When the inner die and the outer die are selected in a matching manner, it is ensured that the cold drawing deformation of the tube blank is greater than the elastic deformation of the tube blank.

[0013] The cold drawing finishing device is used to carry out the cold drawing process of the unqualified products, including the following steps:

[0014] Step 1: Fix and install the fixed core rod, and pass the tube blank through the fixed core rod;

[0015] Step 2: Connect the pull rod to the mounting sleeve of the fixed core rod head through the pull rod head;

[0016] Step 3: According to the spacing requirements between the inner mold and the outer mold, select a spacer of appropriate length to position the inner mold, and fix the inner mold on the tie rod through a locking nut;

[0017] Step 4: initially pass the end of the tube through the inner die and the outer die, and fix the end of the tube with the pull head through a clamp, start the pull head, and pull the tube;

[0018] Step 5: During the drawing process, the tube blank is drawn in the direction of the outer die and the inner die in turn, so that the tube blank is first reduced in diameter and then expanded to achieve the finishing of the inner diameter of the tube.

[0019] The present invention has the following beneficial effects:

[0020] 1. By adopting the finishing device and process of the present invention, the products with excessive dimensional accuracy produced by cold drawing can all be converted into qualified products after cold drawing again, ensuring that the dimensional accuracy of high-strength tube drawing meets the requirements, thereby saving resources and achieving the purpose of waste recycling.

[0021] 2. During the finishing process, the relative position of the inner mold and the outer mold is very important. The distance should be ≥10mm to prevent the inner mold and the outer mold from being too close to each other, which will cause the tube wall to be reduced and fail to achieve the finishing effect.

[0022] 3. The pull rod of the above structure can be used to position and install the inner mold, thereby ensuring the spacing requirement between the inner mold and the outer mold during specific use, and finally ensuring that the inner diameter of the product after finishing meets the design accuracy requirements of the product.

[0023] 4. The hexagonal head makes it easy to fasten the entire pull rod to the fixed core rod when it is docked, and then it is easy to turn and tighten it with a wrench.

[0024] 5. The cold drawing deformation of the tube billet is greater than the elastic deformation of the tube billet. By adopting the deformation control of the above structure, the finishing effect and quality are guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0026] Figure 1 It is a main sectional view of the present invention.

[0027] In the figure: tube blank 1, locking nut 2, inner die 3, spacer sleeve 4, outer die 5, die base 6, tie rod 7, fixed core rod 8, hexagonal head 9, threaded shaft section 10, inner die shaft section 11, spacer sleeve shaft section 12, tie rod head 13, mounting sleeve 14. DETAILED DESCRIPTION

[0028] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0029] Embodiment 1:

[0030] like Figure 1 As shown, a cold drawing finishing device comprises a die base 6, an outer die 5 is fixedly installed inside the die base 6; and an inner die 3 is fixedly installed on a tie rod 7, and the tie rod 7 is fixedly connected to a fixed core rod 8; the inner die 3 and the outer die 5 are used in pairs, and the distance between the inner die 3 and the outer die 5 is ≥10mm. By adopting the cold drawing finishing device of the above structure, the products with dimensional accuracy exceeding the tolerance produced in the cold drawing production process can be cold drawn and finished again to achieve the required dimensional accuracy, and then transformed into qualified products, which achieves the purpose of saving resources and effectively reduces costs.

[0031] During the finishing process, the relative position of the inner mold and the outer mold is very important. The distance should be ≥10mm to prevent the inner mold and the outer mold from being too close to each other, which will cause the tube wall to be reduced and fail to achieve the finishing effect.

[0032] Furthermore, the tie rod 7 includes a tie rod head 13, which is fixedly connected to the mounting sleeve 14 of the head of the fixed core rod 8, and the other end of the tie rod head 13 is a spacer shaft section 12, on which a spacer 4 is mounted, and the other end of the spacer shaft section 12 is an inner mold shaft section 11, on which an inner mold 3 is mounted, and the inner mold 3 is mounted on the inner mold shaft section 11, and the other end of the inner mold shaft section 11 is a threaded shaft section 10, on which a locking nut 2 for limiting the end of the inner mold 3 is mounted. By adopting the tie rod 7 of the above structure, the inner mold 3 can be positioned and installed, thereby ensuring the spacing requirements between the inner mold 3 and the outer mold 5 during specific use, and finally ensuring that the inner diameter of the product after finishing meets the design accuracy requirements of the product.

[0033] Furthermore, the end of the threaded shaft section 10 is provided with a hexagonal head 9. The hexagonal head 9 facilitates the entire pull rod 7 to be tightly connected with the fixed core rod 8 when docking, and then facilitates the rotation and tightening thereof by a wrench.

[0034] Furthermore, the inner diameter of the outer die 5 is 1-4 mm smaller than the outer diameter of the tube blank 1. The above-mentioned dimensional relationship ensures that the tube blank 1 can be reduced in diameter first during the finishing process. Moreover, the above-mentioned dimensions are data obtained through repeated test verification. It is ensured that the best finishing effect can be achieved within this range.

[0035] Furthermore, the outer diameter of the inner mold 3 is 0-2 mm larger than the required inner diameter of the finished product. The above-mentioned dimensional relationship can ensure that the inner hole of the tube blank 1 is finely trimmed to achieve the required size. Moreover, the above-mentioned size is the data obtained by repeated test verification.

[0036] Furthermore, when the inner die 3 and the outer die 5 are selected in a matching manner, it is ensured that the cold drawing deformation of the tube blank 1 is greater than the elastic deformation of the tube blank 1. By adopting the deformation control of the above structure, the finishing effect and quality are guaranteed.

[0037] Embodiment 2:

[0038] The cold drawing finishing device is used to carry out the cold drawing process of the unqualified products, including the following steps:

[0039] Step 1: Fix and install the fixed core rod 8, and pass the tube blank 1 through the fixed core rod 8;

[0040] Step 2: The pull rod 7 is fixedly connected to the mounting sleeve 14 at the head of the fixed core rod 8 through the pull rod head 13;

[0041] Step 3: According to the spacing requirement between the inner mold 3 and the outer mold 5, select a spacer 4 of appropriate length to position the inner mold 3, and fix the inner mold 3 on the pull rod 7 through the locking nut 2;

[0042] Step 4: initially pass the end of the tube blank 1 through the inner die 3 and the outer die 5, and fix the end of the tube blank 1 to the pull head through a clamp, start the pull head, and pull the tube blank 1;

[0043] Step 5: During the drawing process, the tube blank 1 is drawn in the direction of the outer die 5 and the inner die 3 in sequence, so that the tube blank 1 is firstly reduced in diameter and then expanded to achieve the finishing of the inner diameter of the tube.

[0044] Embodiment 3:

[0045] In this embodiment, the size of the tube blank 1 used is 220 / 198.5, the inner hole ovality is 0.6mm, the outer die is 218, and the inner die is 199. After cold drawing by the above device, the inner hole ovality is 0.3mm, which meets the requirements;

[0046] Embodiment 4:

[0047] In this embodiment, the size of the tube blank 1 used is 230 / 198.5. After tempering, the deformation is large, the inner hole ovality is 1mm, and the requirement is <0.5mm. The outer die is 228 and the inner die is 199. After cold drawing by the upper follow-up device, the inner hole ovality is 0.4mm, which meets the requirement.

Claims

1. A cold drawing finishing device, characterized in that: It comprises a mold base (6), an outer mold (5) being fixedly mounted inside the mold base (6); It also includes an inner mold (3), wherein the inner mold (3) is fixedly mounted on a pull rod (7), and the pull rod (7) is fixedly connected to a fixed core rod (8); The inner mold (3) and the outer mold (5) are used in pairs, and the distance between the inner mold (3) and the outer mold (5) is ≥10 mm; The pull rod (7) comprises a pull rod head (13), the pull rod head (13) is fixedly connected to a mounting sleeve (14) of the head of the fixed core rod (8), the other end of the pull rod head (13) is a spacer sleeve shaft section (12), the spacer sleeve shaft section (12) is sleeved with a spacer sleeve (4), the other end of the spacer sleeve shaft section (12) is an inner mold shaft section (11), the inner mold shaft section (11) is sleeved with an inner mold (3), the inner mold (3) is sleeved on the inner mold shaft section (11), the other end of the inner mold shaft section (11) is a threaded shaft section (10), the threaded shaft section (10) is mounted with a locking nut (2) for limiting the end of the inner mold (3); The inner diameter of the outer die (5) is 1 to 4 mm smaller than the outer diameter of the tube blank (1); During the drawing process, the tube blank (1) is drawn in the direction of the outer die (5) and the inner die (3) in sequence, so that the tube blank (1) is firstly reduced in diameter and then expanded to achieve the precision adjustment of the inner diameter of the tube.

2. A cold drawing finishing device according to claim 1, characterized in that: The end of the threaded shaft section (10) is provided with a hexagonal head (9).

3. A cold drawing finishing device according to claim 1, characterized in that: The outer diameter of the inner mold (3) is 0-2 mm larger than the required inner diameter of the finished product.

4. A cold drawing finishing device according to claim 1, characterized in that: When the inner die (3) and the outer die (5) are selected in a matching manner, it is ensured that the cold drawing deformation of the tube blank (1) is greater than the elastic deformation of the tube blank (1).

5. The cold drawing finishing device according to any one of claims 1 to 4 is used to carry out the cold drawing process of unqualified products, characterized in that The following steps are involved: Step 1: fix and install the fixed core rod (8), and pass the tube blank (1) through the fixed core rod (8); Step 2: The pull rod (7) is fixedly connected to the mounting sleeve (14) at the head of the fixed core rod (8) via the pull rod head (13); Step 3: According to the spacing requirement between the inner mold (3) and the outer mold (5), a spacer (4) of appropriate length is selected to position the inner mold (3), and the inner mold (3) is fixed to the pull rod (7) by means of a locking nut (2); Step 4: initially passing the end of the tube blank (1) through the inner die (3) and the outer die (5), and fixing the end of the tube blank (1) to the pull head through a clamp, starting the pull head, and pulling the tube blank (1); Step 5: During the drawing process, the tube blank (1) is drawn in the direction of the outer die (5) and the inner die (3) in sequence, so that the tube blank (1) is firstly reduced in diameter and then expanded to achieve the precision adjustment of the inner diameter of the tube.

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