JP2000158077A - Screw forging method, and thread rolling tool therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a screw equivalent to a chemically-polished screw at a low cost with the same number of processes as that of the regular screw by forging the screw simultaneously roll-thread rolling using a chemically- polished thread rolling tool. SOLUTION: Projecting threads are approximately parallel to each other in a form rolling surface of a thread rolling tool, and preferably chemically polished in manufacturing a thread rolling die. The thread rolling die is preferably and chemically polished by stainless steel chemical abrasive glossy material. After a head part is formed in a rolling process, threads are formed using the thread rolling die, and at the same time, the surface of the screw is forged by the thread rolling die, and the surface is heat treated, oil during the machining is incinerated, and the oil on the screw surface is chemically removed by the pickling, burrs and chips are removed in the barrel treatment, and cleaned with water for finishing. The cost is reduced since the chemical polishing treatment need no large equipment such as the buffing or electrolytic polishing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw forging method and a thread rolling tool according to the method.

[0002]

2. Description of the Related Art Generally, a method of rolling a screw will be described with reference to FIG. 2 as an example. A head (having a diameter larger than the diameter of a leg) is cut into a material (not shown) cut to a predetermined size in a forging step 1. Then, in a rolling process 2, a thread is rolled on the leg. Thereafter, the surface is subjected to a heat treatment in a heat treatment step 3 to incinerate an oil component at the time of forming, and furthermore, an oil component on the screw surface is chemically removed in an acid pickling step 4, and then the forging step or the Eliminates burrs, chips, etc. generated when the material is cut. Then, as the finishing of the material, the screw material is washed with water in a finishing processing step 6. In general, when improving the smoothness of the screw surface and further forging the screw, after finishing the finishing step 6, in the surface treatment step 7, the screw is manufactured through a surface treatment such as a chemical polishing treatment. Was something.

[0003]

However, even with the above-mentioned conventional method of thread rolling, there are the following problems. After the normal screw manufacturing process as described above, the chemical polishing treatment performed to further improve the smoothness of the screw surface not only occupies a large part of the cost of screw manufacturing, but also requires skill and equipment, so it is low. It was difficult to manufacture screws and mass-produce screws at a cost. In particular, in the manufacture of HDD-related screws, the chemical polishing treatment performed at the time of manufacture occupies much of the screw manufacturing cost.

[0004] The present invention has been made in view of the above-described problems in the prior art, and has the same number of steps as a normal screw.
An object of the present invention is to provide a low-cost screw equivalent to a screw subjected to a chemical polishing treatment.

[0005]

The first invention of the present application for solving the above-mentioned problems is characterized in that a screw is forged at the same time as the screw is rolled by using a screw rolling tool subjected to a chemical polishing treatment. And

Therefore, according to the screw forging method of the first invention of the present application, forging can be performed simultaneously with the screw rolling by using a screw rolling tool which has been subjected to chemical polishing in advance.
There is an advantage to improve the smoothness of the thread surface to be rolled,
There is an advantage that a surface treatment step after thread rolling can be omitted. The forging in this case means to make the screw surface smooth at the time of thread rolling. Further, since the thread rolling tool has been subjected to chemical polishing in advance,
Since the smoothness of the surface of the thread rolling tool is improved and friction between the materials can be reduced, there is an advantage that the life of the thread rolling tool can be extended.

A second invention of the present application is the screw forging method according to the first invention of the present application, wherein the chemical polishing treatment is performed on at least a rolled surface.

[0008] Therefore, according to the screw forging method of the second invention of the present application, since the chemical polishing treatment is performed on at least the roll-formed surface, the roll forming surface of the screw-rolled tool can be rolled. There is an advantage that the abrasion due to repetition can be reduced and the surface of the screw rolled by the previously rolled surface can be made smooth.

In a third aspect of the present invention, in the screw forging method according to the first or the second aspect of the present invention, the thread rolling tool includes a convex thread formed substantially parallel to the thread. By having a rolling surface provided, by being relatively rolled in a state where the workpiece is pressed against the rolling surface,
A rolling die for performing rolling on the outer peripheral surface of the workpiece, and a chemical polishing treatment is performed at the time of manufacturing the rolling die. Rolling and forging of a screw are performed using the rolling die. It is characterized by the following.

[0010] Therefore, according to the screw forging method of the third invention of the present application, since the chemical polishing treatment is performed at the time of manufacturing the rolling dies, the smoothness of the surface of the rolling dies is improved,
From reducing the friction between the rolling die and the material,
The life of the rolling die can be extended, and the surface of the screw to be rolled can be formed smoothly, so that after the screw is rolled, a surface treatment step for smoothing the surface of the screw is omitted. There are advantages that can be.

According to a fourth aspect of the present invention, there is provided a method for forging a screw according to any one of the first to third aspects of the present invention, wherein a chemical polishing treatment performed on a rolling die is performed by stainless steel chemical polishing. Characterized by chemical polishing treatment with an agent

Therefore, according to the screw forging method of the fourth invention of the present application, the chemical polishing treatment to be performed on the rolling die is a chemical polishing treatment using a stainless steel chemical polishing brightener, so that any shape can be chemically polished. Processing, after polishing, can improve the smoothness of the rolling die surface,
There is an advantage that corrosion resistance can be improved.
In addition, chemical polishing using a stainless steel chemical polishing brightener is not a polishing that requires skill like buff polishing or electrolytic polishing, and has the advantage of being able to reduce costs because it does not require large-scale equipment. Further, the chemical polishing treatment using a stainless steel chemical polishing brightener is superior in the gloss as compared with the surface treatment by electrolytic polishing.
The chemical polishing treatment using a stainless steel chemical polishing brightener includes a chemical polishing treatment by the Nepros method.

According to a fifth aspect of the present invention, there is provided the screw forging method according to any one of the first to fourth aspects of the present invention, wherein a chemical polishing treatment with a stainless steel chemical polishing brightener is performed. In using the rolled die thus formed for rolling a screw, for example, after first forming a head in a pressing process,
At the same time as forming a screw thread using the rolling die in the rolling process, forging the surface of the screw with the rolling die and then performing heat treatment, pickling, barrel processing, and washing the material with water as a finish. It has a manufacturing process.

Therefore, according to the screw forging method of the fifth invention of the present application, when a rolled die that has been subjected to a chemical polishing treatment with a stainless steel chemical polishing brightener is used for rolling a screw, for example, firstly in a pressing process. After forming the head, at the same time as forming the screw thread using the rolling dies in the rolling process, forging the surface of the screw with the rolling dies, then heat treatment, pickling, barrel processing, and finish The feature is that it has a normal screw manufacturing process of washing the material with water, so the same number of processes as normal screw rolling can produce the same product as a chemically polished screw, which has the advantage of reducing costs. is there.

The sixth invention of the present application is a thread rolling tool obtained by performing a chemical polishing treatment with a stainless steel chemical polishing brightener.

Therefore, according to the thread rolling tool of the sixth and seventh aspects of the present invention, the thread rolling tool can be obtained by performing a chemical polishing treatment with a stainless steel chemical polishing brightener, so that the Has the advantages of improving the smoothness of the die, reducing friction with the material, improving corrosion resistance, and extending the life of the die. Further, by using the thread rolling tool at the time of thread rolling, there is an advantage that the smoothness of the surface of the thread to be rolled can be improved. In addition, since chemical polishing using a stainless steel chemical polishing brightener is not a chemical polishing process requiring skill like buff polishing or electrolytic polishing, there is an advantage that production and mass production are easy. still,
As a chemical polishing treatment using a stainless steel chemical polishing brightener, there is known a chemical polishing treatment by a so-called Nepros method.

According to an eighth aspect of the present invention, there is provided the thread rolling tool according to the sixth or seventh aspect of the present invention, wherein the chemical polishing using the stainless steel chemical polishing brightener is at least performed by rolling. It is characterized by being applied to a surface.

Therefore, according to the thread rolling tool of the eighth aspect of the present invention, since the rolling die is formed on at least the rolled surface by chemical polishing using a stainless steel chemical polishing brightener, the screw rolling tool is formed. There is an advantage that the smoothness of the screw surface can be improved during fabrication. Further, there is an advantage that the life of the rolled surface of the thread rolling tool is extended.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A screw forging method and a thread rolling tool according to an embodiment of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a view showing a method of forging a screw and a process of a thread rolling tool according to the embodiment of the present invention. The screw forging method of the present invention is a method of rolling a screw using a screw rolling tool (not shown) that has been subjected to a chemical polishing treatment with a stainless steel chemical polishing brightener. In the present embodiment, the thread rolling tool is a rolling die as an example. In FIG. 1, a head (having a diameter larger than the diameter of a leg) is formed by forging in a material (not shown) cut to a predetermined size in a forging step 1, and then a thread is formed on the leg in a rolling step 2. Make it. At this time, in the rolling step 2, the rolling process is performed using the rolling die that has been subjected to the chemical polishing treatment with a stainless steel chemical polishing brightener to form a screw thread and at the same time the surface of the screw is rolled into the rolling die. And forge. After that, the surface is subjected to a heat treatment in a heat treatment step 3 to incinerate oil at the time of forming processing, and further, an oil component on a screw surface is chemically removed in an acid pickling step 4, and then the forging step or the above in a barrel treatment step 5. Burr generated when the material is cut,
Remove chips and the like. Then, as the finishing of the material, the screw material is washed with water in a finishing processing step 6 and then commercialized. In some cases, the finishing step 6
After passing through, the surface of the screw is made cosmetic by applying cosmetics to give the screw an aesthetic appearance, but the description is omitted in the present embodiment.

The above-mentioned stainless steel chemical polishing brightener will be described with reference to FIG. FIG. 2 is a process chart showing the steps of chemical polishing using a stainless steel chemical polishing brightener. The stainless steel chemical polishing brightener described here does not contain hydrofluoric acid and has an extremely high acid concentration of 3% or less. The chemical polishing treatment using a stainless steel chemical polishing brightener can be classified into four steps: a pretreatment step 8, a polishing treatment step 9 (polishing operation using an abrasive), a neutralization treatment step 10, and a finishing treatment step 11. Are roughly divided into The pretreatment step 8 includes a degreasing treatment step 12
To remove the oil, then remove the scale in a scale removing process 13 and activate the metal surface in an activation process 14. If there is no scale after the degreasing step 12, the scale removing step 13 can be omitted. Next, in the polishing treatment step 9, a stainless steel chemical polishing brightener, which is a polishing liquid, is prepared (not shown), and includes an actual polishing work step (not shown). In the polishing operation, the material was gently put in while the solution of the stainless steel chemical polishing brightener was boiled, and after sufficiently contacting the solution with the stainless steel chemical polishing brightener, the material was taken out after 3 to 7 minutes. It is to be washed. Then, in the neutralization treatment step 10 of the next step, the polishing liquid that could not be completely removed by washing only with water is neutralized with a neutralizing agent, and a passivation treatment is performed in the finishing step of the next step to perform oxidation. A film is formed to maintain gloss after polishing and improve corrosion resistance. After the above steps, the material is washed with water, washed with hot water and dried, and this is subjected to a chemical polishing treatment with a stainless steel chemical polishing brightener. Also, there is a so-called nepros as a stainless steel chemical polishing brightener, and a chemical polishing treatment called a nepros method in which chemical polishing is performed using the nepros is known.

The above-described screw manufacturing process is an example, and no matter what kind of screw manufacturing process is performed, the screw is rolled using the above-mentioned rolling die that has been chemically polished with a stainless steel chemical polishing brightener. When the manufacturing is performed, the smoothness of the screw surface is improved, and the chemical polishing treatment step for improving the smoothness of the screw surface after the manufacturing in the finishing step can be omitted. In other words, since forging is possible at the same time as screw rolling, the use of a screw rolling tool that has been chemically polished with a stainless steel chemical polishing brightener allows chemical polishing to be performed in the same number of steps as normal screws. It is possible to manufacture a product equivalent to the screw that has been performed.

[Brief description of the drawings]

FIG. 1 is a process diagram of a screw forging method according to an embodiment of the present invention.

FIG. 2 is a process diagram of a chemical polishing treatment using a stainless steel chemical polishing brightener according to the embodiment of the present invention.

FIG. 3 is a process diagram of a conventional screw forging method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Forging process 2 Rolling process 3 Heat treatment process 4 Pickling process 5 Barrel process process 6 Finishing process 7 Surface treating process 8 Pretreatment process 9 Polishing process 10 Neutralizing process 11 Finishing process 12 Degreasing process 13 Scale removal Processing Step 14 Activation Processing Step

Claims (7)

[Claims] 1. A method for forging a screw, comprising forging the screw simultaneously with the rolling of the screw using a screw rolling tool subjected to a chemical polishing treatment. 2. The screw forging method according to claim 1, wherein the chemical polishing treatment is performed on at least a rolled surface. 3. The thread rolling tool according to claim 1, wherein the thread rolling tool has a roll-formed surface on which convex threads are provided substantially in parallel, and the workpiece is relatively pressed against the roll-formed surface. A rolling die that is rolled to perform rolling on the outer peripheral surface of the workpiece, and a chemical polishing treatment is performed at the time of manufacturing the rolling die, and a screw is formed using the rolling die. 3. The method according to claim 1, wherein rolling and forging are performed. 4. The screw forging method according to claim 1, wherein the chemical polishing performed on the rolling die is a chemical polishing using a stainless steel chemical polishing brightener. . 5. When the rolling die subjected to the chemical polishing treatment with a stainless steel chemical polishing brightener is used for rolling a screw, for example, first, a head is formed in a pressing process, and then the rolling process is performed in the rolling process. At the same time as forming a screw thread using a forming die, forging the surface of the screw with the rolling die, then performing a heat treatment, pickling, barrel processing, and having a normal screw manufacturing process of washing the material with water as a finish. The method for forging a screw according to claim 1, wherein the screw is forged. 6. A thread rolling tool obtained by subjecting a stainless steel chemical polishing brightener to a chemical polishing treatment. 7. The thread rolling tool according to claim 6, wherein a chemical polishing treatment with the stainless steel chemical polishing brightener is performed on at least a rolled surface.