A composite process for cold heading of 10.9 grade non-adjustable steel headed bolts

Abstract

The invention discloses a composite process method for cold forging of 10.9-grade non-adjustable steel headed bolts, which comprises the following steps: blank preparation, cold forging forming one, cold forging forming two, and subsequent treatment. The advantages of the invention over the prior art are that the invention realizes the production of high-quality bolts through fine steps, and the process method not only improves production efficiency, but also ensures the reliability and durability of the final product.

Description

Technical Field

[0001] The invention relates to the technical field of composite processes, in particular to a composite process method for cold heading of 10.9-grade non-adjustable steel headed bolts. Background Art

[0002] Bolts are a common fastener, widely used in machinery, construction, automobiles, aerospace and other fields. The material of the bolt can vary depending on the application. Commonly used ones include carbon steel, alloy steel, stainless steel, etc. Choosing the right material is crucial to ensure the performance of the bolt. For large or high-strength bolts, hot forging is usually used, that is, forging the metal into the required shape at high temperature. For smaller bolts, cold forging may be used, and they are pressed into shape by a mold at room temperature.

[0003] In the manufacturing process of high-strength bolts, traditional forming processes often rely on heat treatment to achieve the required mechanical properties. However, this method may cause the material hardness to increase while the plasticity decreases, making the bolts prone to cracks or other defects during the forming process. In addition, the traditional cold heading forming process imposes a large deformation ratio on the material during the one-time forming process, which is easy to damage the toughness of the material, resulting in a low yield rate, and the lack of precision in head forming and thread processing affects the final quality and performance of the bolts. For high-strength non-quenched and tempered steel such as grade 10.9, if the conventional cold heading process is used, the risk of fracture during the forming process is easily increased due to the hardening of the material. Therefore, the existing bolt forming process still faces many challenges in improving material utilization, ensuring the quality of finished products, and improving production efficiency.

[0004] The reason why 10.9 grade non-adjustable steel bolts cannot be produced at present is that if a blank with a higher hardness is selected, it will be difficult to form, especially bolts with heads cannot be formed, while if a material with a lower hardness is selected, it will not reach the specified strength grade after cold heading deformation. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the above technical defects and provide a composite process method for cold heading of 10.9 grade non-adjustable steel headed bolts which not only improves production efficiency but also improves the reliability and durability of the final product.

[0006] In order to solve the above problems, the technical solution of the present invention is: a composite process method for cold heading of 10.9 grade non-adjustable steel headed bolts, the process method comprising the following steps:

[0007] Step 1: Blank selection: Select the 10.9 grade non-adjustable steel material that meets the requirements, ensure that the material has high plasticity and low hardness, and calculate and prepare the blank of appropriate length according to the specifications and dimensions of the bolt;

[0008] Step 2: Cold heading forming 1: Reduce the damage to the material toughness by reducing the single shrinkage deformation ratio; by adding an integral shrink rod in front of the cold heading machine, the material enters the cold heading stage before the dislocation hardening of the material has fully formed the hardening effect, avoiding the risk of cold heading cracking due to excessive hardness of the material;

[0009] Step 3: Cold heading forming 2: Place the blank in the mold of the cold heading machine. Through the relative up and down movement of the mold, the blank undergoes plastic deformation in the mold cavity. During the cold heading process, the height of the blank gradually decreases and the cross-section gradually increases, forming the initial shape of the bolt.

[0010] Furthermore, based on the 10.9 grade non-adjustable steel material described in steps 1 to 4, bolts of M6 to M10 are selected.

[0011] The advantages of the present invention compared with the prior art are:

[0012] (1) The composite process method of the present invention ensures the adaptability and consistency of the blank in subsequent processing by selecting 10.9 grade non-adjustable steel material with high plasticity and low hardness and accurately calculating the blank size. The cold heading forming step enables the blank to form the initial shape of the bolt in the mold cavity, reducing the difficulty of subsequent processing. The extrusion forming step further optimizes the accuracy of the bolt head and thread, improves the mechanical properties of the product, and can eliminate the high temperature tempering process, reduce energy consumption and reduce carbon emissions.

[0013] (2) In the second step of cold heading, the composite process method of the present invention effectively protects the toughness of the material and avoids cracking caused by hardening of the material during the cold heading process by reducing the single surface shrinkage deformation ratio and adding an overall rod shrinkage process before the cold heading machine.

[0014] (3) The composite process method of the present invention adds an integral rod shrinkage before cold forging, and uses the cold work hardening formation period to complete the cold forging. At the same time, because there is a certain temperature rise during the integral rod shrinkage, a forming effect similar to warm forging is obtained. DETAILED DESCRIPTION

[0015] The specific embodiments of the present invention are further described below.

[0016] In order to make the contents of the present invention more clearly understood, the technical solutions in the embodiments of the present invention are described clearly and completely.

[0017] A composite process for cold heading of 10.9 grade non-adjustable steel headed bolts, the process comprising the following steps:

[0018] Step 1: Billet selection

[0019] Material selection: Choose non-quenched and tempered steel materials that meet the 10.9 grade strength requirements. This type of steel usually has good comprehensive mechanical properties and is suitable for manufacturing high-strength bolts.

[0020] Material properties: Ensure that the selected material has high plasticity and low hardness to facilitate subsequent cold heading.

[0021] Calculation of blank length: Calculate the length of the blank according to the bolt specifications to be manufactured (such as M6, M8, M10). The length calculation should take into account the finished product size and the material loss during the cold heading process.

[0022] Blank preparation: Cut the blank into appropriate length according to the calculation results and prepare to proceed to the next step.

[0023] Step 2: Cold heading forming

[0024] Placing the blank: Place the prepared blank into the die of the cold heading machine.

[0025] Die setting: Adjust the position of the die to ensure that the blank is evenly stressed during cold forging.

[0026] Cold heading operation: Start the cold heading machine to make the die move up and down relative to each other, forcing the blank to undergo plastic deformation in the die cavity. In this process, the height of the blank will decrease, while the cross-sectional area will increase, thus forming the basic shape of the bolt.

[0027] Step 4: Cold heading forming 2

[0028] Reduce the deformation ratio: adjust the parameters of the cold heading machine to reduce the single shrinkage deformation ratio to reduce the damage to the material toughness.

[0029] Integral rod shrinking: Add an integral rod shrinking process before the cold heading machine to avoid the problem of cold heading cracking due to premature hardening of the material.

[0030] Step 5: Subsequent processing

[0031] Cleaning: Clean the bolts with an appropriate cleaning agent to remove surface residue.

[0032] Heat treatment: The bolts shall be heat treated as needed, such as quenching, tempering, etc., to improve their hardness and toughness.

[0033] Surface treatment: Surface treatment such as galvanizing, nickel plating, phosphating, etc. is performed to enhance the corrosion resistance of the bolts.

[0034] It should be noted that throughout the manufacturing process, temperature and pressure must be strictly controlled to ensure the quality and performance of the final product. After each step, the product should be tested as necessary to ensure that it meets the design requirements and relevant standards. Equipment needs to be maintained regularly to ensure that the machine runs well and reduce failure rates.

[0035] In specific use: First, select non-quenched and tempered steel that meets the 10.9 grade standard as the blank material to ensure that the material has good plasticity and low hardness, and calculate the appropriate blank length according to the size of the M6 ​​to M10 specification bolts to be manufactured for preparation; then, put the prepared blank into the mold of the cold heading machine, and through the pressure of the relative movement of the mold up and down, the blank is plastically deformed in the mold cavity, the blank height is reduced and the cross-section is increased, thereby obtaining the basic shape of the bolt; then, on this basis, continue to use the extrusion die to form the head of the bolt and process the threaded part. During the extrusion process, the metal is deformed under the action of the die. The material flows and finally forms the required specific shape and size. After that, the parameters of the cold heading machine are adjusted to reduce the single shrinkage deformation ratio, reduce the damage to the material toughness, and add an overall rod shrinking process before the cold heading machine, so that the material enters the cold heading stage before it is completely hardened, so as to avoid the problem of cracks during cold heading due to the material being too hard. Finally, the formed bolts are deburred, cleaned and other post-processing processes to improve the surface finish and overall quality of the product, and the bolts are heat treated and surface treated according to actual needs, which can eliminate the high-temperature quenching and tempering process, reduce energy consumption and reduce carbon emissions, so as to improve the mechanical properties and corrosion resistance of the bolts. The entire process ensures that the final bolts produced meet the requirements of high strength and high precision by finely controlling the parameters of each step.

[0036] The present invention and its implementation methods are described above, and such description is not restrictive, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design structures and embodiments similar to the technical solution without creativity, which should all fall within the protection scope of the present invention.

Claims

1. A composite process for cold heading of 10.9 grade non-adjustable steel headed bolts, characterized in that: The process comprises the following steps: Step 1: Blank selection: Select the 10.9 grade non-adjustable steel material that meets the requirements, ensure that the material has high plasticity and low hardness, and calculate and prepare the blank of appropriate length according to the specifications and dimensions of the bolt; Step 2: Cold heading forming 1: Reduce the damage to the material toughness by reducing the single shrinkage deformation ratio; by adding an integral shrink rod in front of the cold heading machine, the material enters the cold heading stage before the dislocation hardening of the material has fully formed the hardening effect, avoiding the risk of cold heading cracking due to excessive hardness of the material; Step 3: Cold heading forming 2: Place the blank in the mold of the cold heading machine. Through the relative up and down movement of the mold, the blank undergoes plastic deformation in the mold cavity. During the cold heading process, the height of the blank gradually decreases and the cross-section gradually increases, forming the initial shape of the bolt.

2. According to claim 1, a composite process for cold heading of 10.9 grade non-adjustable steel headed bolts, characterized in that: Based on the 10.9 grade non-adjustable steel material described in steps 1 to 4, M6 to M10 bolts are selected.