JPH0972326A - Manufacture of screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To completely remove oil content from raw material by carrying out heat treatment on the surface of the raw material for a screw formed of a head part and a leg part, and executing pickling and barrel treatment for removing adhering carbide, burr and chip to carry out a passivation process for forming an oxide film on the surface of the raw material, and washing it. SOLUTION: A head part is formed in a forging process 1, and a screw thread is formed in a leg part in a thread rolling process 2. Heat is applied to a raw material in a heat treatment process 3 to burn oil content given in the case of forming process. In order to remove the carbide of oil content produced in the heat treatment process 3, the raw material is immersed in acid solution in a pickling process 4. Burrs and chips caused in the forging process 1 and the thread rolling process 2 are removed in a barrel process 5, and in order to oxidize the raw material surface in a passivation process 6 to improve anticorrosion ability, the raw material is immersed in the oxidizing agent solution composed of nitric acid, diluted nitric acid, chromic acid, etc. The raw material is washed in a finishing process 7. The oil content is thoroughly removed by finishing the above treatment. Thus resin material can be completely prevented from causing a breakage and a crack in it by the penetrating of the oil content.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing screws used for these parts in the electronic device industry such as computer devices, information communication devices, and optical disks which have been recently developed.

[0002]

2. Description of the Related Art In the industrial field of such electronic communication equipment, storage media such as optical disks and magnetic disks are often used, and these storage media are usually used for preventing scratches or for carrying. For the sake of simplicity, it is housed in a resin housing case, and the storage medium in this case operates during use. And this case is usually assembled by screwing a screw into a resin, and the screw is often used.

However, this screw is manufactured by the conventional manufacturing method, and is manufactured by the process shown in FIG. Stainless steel is used as the material of the screw because the screw used for these purposes is used where the screw used for these purposes does not like oil, moisture, rust and the like. Then, this stainless steel wire rod is cut into a predetermined size in advance to manufacture a raw material, and a head having a diameter larger than that of the leg portion is formed at one end of the raw material in the forging process 101. Next, a thread is thread-formed on this leg portion in a rolling step 102, and the form as a screw is completed in these forging and rolling steps.

When the form of the screw is completed in this way, the screw material (not shown) is moved to the barrel processing step 103, and burrs generated in the previous step and cutting chips attached to the screw material are removed. To be removed. After that, in the next finishing process 104, plating or makeup is applied as required, and subsequently the screw as a product is packaged.

[0005]

As described above, in the general screw manufacturing method, a large amount of lubrication is usually used to prevent seizure between the punch or the rolling die and the material in the forging and rolling processes. Oil is used, and these oils are removed by the time it is shipped as a product.However, when used in the industrial field such as recent electronic communication equipment, it is not a problem before. The remaining oil subtly affects the product. If you use this screw to assemble a storage case for optical disks, magnetic disks, etc. due to the oil that is slightly attached to one of them,
This oil gradually penetrates into the resin material, and the resin material often breaks or cracks at the screw part that assembles the storage case.

Further, since a computer device or the like using such a disk is extremely reluctant to dust, the presence of this oil easily causes the dust to adhere to the computer device, which also causes a malfunction of the computer device. Further, in a hard disk of a computer device, when silicon gas is generated, this storage medium is adversely affected. Therefore, the silicon-based lubricating oil used in the screw manufacturing cannot be used in the screw manufacturing for these products. There are problems such as not being.

An object of the present invention is to solve the above problems and to change the forging and rolling forming process without
It is to obtain a method for completely removing oil from a molded screw material.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a stainless steel screw in which a head having a diameter larger than that of a leg is press-formed on a material having a predetermined size, and a thread is thread-formed on the leg. The surface of the screw material consisting of the threaded portion and the leg portion in which the screw thread is formed in the heat treatment step 3, and subsequently in the pickling treatment step 4 and the barrel treatment step 5, the carbide adhered to the screw material and the To remove burrs and chips generated during processing, acid pickling and barreling are performed, and then passivation step 6 in the next step forms an oxide film on the surface of the screw material to form a metal surface. This can be achieved by providing a method for manufacturing a screw, in which a stabilizing passivation treatment is performed, and then, in a finishing treatment step 7, the screw material is washed with water.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In FIG. 1, a screw material in which a head having a diameter larger than the leg diameter is press formed on a material (not shown) cut to a predetermined size, and a thread is rolled on the leg. (Not shown) is transferred to the heat treatment step 3 arranged as the next step. In this heat treatment step 3, heat is applied to the screw material,
Incinerates oil during molding. Then, in order to remove the carbides of the incinerated oil component, in step 4 of the pickling treatment, the material is dipped in an acidic solution and pickled. As a result, the surface of the screw material becomes beautiful, but this screw material is further transferred to the barrel processing step 5 in the next step to remove deposits such as burrs and cutting chips generated in the molding step.

After this, the stainless steel screw material is transferred to the passivation treatment step 6 to perform surface treatment. As a result, an oxide film is formed on the surface of the screw material made of stainless steel, the corrosion resistance of the screw material becomes very good, the corrosion reaction of the screw material is prevented, and it becomes stable. Then, after the above processing is finished, the screw material is washed with water in the finishing treatment step 7 to obtain a screw as a product from which oil is completely removed.

[0011]

Embodiments of the present invention will be described in detail below with reference to FIG. In the figure, reference numeral 1 is a forging process for forming a head having a diameter larger than that of a leg on one end of a material (not shown) that has been cut into a predetermined size. Following this forging process 1, a rolling process 2 for forming a thread on the leg is arranged.
The screw material (not shown) formed in the forging process 1 and the rolling process 2 is transferred to the heat treatment process 3 arranged as the next process. After the heat treatment step 3, the heat treatment step 3 is performed.
There is a pickling step 4 for removing the carbide of the oil component generated in step 2, in which the screw material is immersed in an acidic solution.

Next to the pickling step 4, there is arranged a barrel processing step 5 for removing burrs and chips generated during the forming in the forging step 1 and the rolling step 2. Next, a passivation treatment step 6 of immersing the screw material in an oxidizer solution such as nitric acid, dilute nitric acid, or chromic acid for performing a passivation treatment for oxidizing the surface of the screw material to improve the corrosion resistance of the screw material is provided. Has been. After this passivation treatment step 6, a finishing treatment step 7 is arranged, and in this step, the screw material is washed with water.

For this reason, a head having a diameter larger than the leg diameter is press-formed with respect to the material cut into a predetermined size, and subsequently, the screw material having the thread thread rolled on the leg is transferred to the heat treatment step 3. . In this heat treatment step 3, heat is applied to the screw material to incinerate the oil content during the molding process. Then, the incinerated charcoal of the oil component is removed by performing pickling treatment in an acidic solution. This makes the surface of the screw material beautiful. Further, this screw material is transferred to the barrel processing step 5 to remove deposits such as burrs and cutting chips generated in the molding step.

After this, the stainless steel screw material is transferred to passivation treatment step 6 and subjected to a surface treatment, and an oxide film is formed on the surface of the stainless steel screw material, resulting in very good corrosion resistance. In this state, the corrosion reaction of the screw material is prevented, and a stable state is achieved. In this way, after the above processing is completed, the screw material is washed with water to obtain a screw as a product from which oil has been completely removed.

[0015]

As is apparent from the embodiments described above, according to the present invention, the surface of the screw material is heat-treated in the heat treatment step 3, and subsequently the thread material is attached to the screw material in the pickling treatment step 4 and the barrel treatment step 5. To remove burrs, burrs, chips, etc. generated during the processing of the above-mentioned carbide and the above-mentioned material, and then perform a passivation treatment step 6 to form an oxide film on the surface of the screw material to form a metal film. Since this is a screw manufacturing method that prevents surface corrosion reaction and is washed with water in the next finishing step 7, when this screw is used in the industrial field of recent electronic communication equipment, etc., the oil content attached to the screw is Even if this screw is used for a storage case for optical disks, magnetic disks, etc., oil will not penetrate into the resin material and the resin material will break at the screw part that assembles the storage case. Bi becomes nothing that enters. Also,
Even if a large amount of lubricating oil is used to prevent seizure when forming the material by punching or rolling die, the oil is completely removed from the screw, so no special forming tool is required and the processing cost is reduced. To be done. Further, even when used for assembling a computer device or the like that uses a storage medium such as an optical disk or a magnetic disk, since the screw has no oil content, dust is unlikely to adhere to the screw and the breakdown of the computer device is reduced. Moreover,
Even if silicon-based lubricating oil is used for forging and rolling,
Silicon gas is not generated from the screw during use of the hard disk or the like of the computer device, and a peculiar effect such as not adversely affecting the storage medium is obtained.

[Brief description of drawings]

FIG. 1 is a process chart showing an embodiment of the present invention.

FIG. 2 is a process chart showing a conventional example of the present invention.

[Explanation of symbols]

 1 Pressing process 2 Rolling process 3 Heat treatment process 4 Pickling treatment process 5 Barrel treatment process 6 Passivation treatment process 7 Finishing treatment process

Claims (1)

[Claims] 1. A stainless steel screw in which a head having a diameter larger than that of a leg portion is press-formed on a material having a predetermined size, and a thread is thread-formed on the leg portion. The surface of the screw material consisting of and is subjected to a heat treatment in the heat treatment step 3, and subsequently, in the pickling treatment step 4 and the barrel treatment step 5, the carbide adhered to the screw material and the burrs, chips, etc. generated during the processing of the material are removed. A pickling treatment and a barrel treatment are performed to remove the impurities, and then a passivation treatment step 6 of the next step is performed.
A method for producing a screw, wherein an oxide film is formed on the surface of the screw material to passivate it to stabilize the metal surface, and the screw material is washed with water in the next finishing treatment step 7.