KR20030036365A - A heat treatment process of seat and valve for automatic transmission - Google Patents

Abstract

PURPOSE: A method for heat treating valve and seat for automatic transmission is provided to improve productivity through heat treatment process appropriate for stainless steel parts and manufacture superior products through stabilization of quality. CONSTITUTION: The method for heat treating valve and seat for automatic transmission comprises degreasing process of uniformly heat treating the product, wherein the product is degreased using TCE (trichloroethylene) after aligning the product using an exclusive jig to remove oil stuck to the surface of a mechanically processed product; preheating process of preheating the degreased product in a preheating furnace having a temperature of 300 to 350 deg.C for one hour; nitriding process of nitriding the preheated product in a nitriding furnace having a temperature of 570 deg.C for 40 minutes to one hour; cooling process of air cooling the nitrided product to a temperature of 150 deg.C or less in air and water cooling the air cooled product in an alkali washing vat; washing process of air shooting the cooled product in hot water having a temperature of 40 deg.C or more using shot balls having a size of 0.2 to 0.5 mm; drying process of drying the air shot product in an electric furnace having a temperature of 150 to 180 deg.C for one or more hours; and sanding process of sanding the dried product using glass having a size corresponding to a sieve size of 100 to 170 mesh.

Description

A heat treatment process of seat and valve for automatic transmission

The present invention relates to a method for manufacturing weak quality heat treatment of valves and seats of stainless steel, and more particularly, to a method for manufacturing heat treatment of valves and seats used in an automatic transmission of a vehicle.

Looking at the process of the heat treatment method of the valve and seat in general;

First, it consists of the preheating process, the preheating process, the nitriding process, the cooling process, the washing process, the drying process, and the sanding process.

However, in the conventional heat treatment methods, preheating is performed at 250 ° C to 400 ° C, and nitriding is performed at 570 ° C for 1 to 3 hours. In the cooling process, the surface hardness of the product is in the process of air cooling at 200 ~ 350 ℃, rinsing with hot water and drying process to remove moisture from the electric furnace at 100 ~ 150 ℃. In the last sanding process, the edges of the product are broken and a large amount of defective products are generated, resulting in a decrease in productivity and quality problems of the product. It also became.

Accordingly, an object of the present invention for solving the above problems is to provide a product having excellent wear resistance through a heat treatment process suitable for the parts of SUS steel.

The present invention for achieving the above object,

First, a degreasing process is necessary for uniform heat treatment of the product.

The degreasing process is a process for removing grease on the surface of a machined product, using a dedicated jig to align the product and degreasing it using T.C.E.

After a preheating process for 1 hour in a preheating furnace at 350 ° C., a nitriding process for 40 minutes to 1 hour in a 570 ° C. nitriding furnace,

Cooling process to cool water in air and alkali washing tank under 200 ℃ in air, washing process to short-circuit with 0.2 ~ 0.5m / m shot ball in hot water, and electric furnace of 150 ~ 180 ℃ A heat treatment process consisting of a drying process of more than 1 hour and a sanding process of sanding using 100 to 170 mesh of glass was implemented.

1 is an overall process diagram according to a preferred embodiment of the present invention.

Hereinafter, the detailed description of the preferred embodiment of the present invention will be described in detail according to the implementation process.

First, the concept of the heat treatment process to be proposed in the present invention is to propose to provide a product having excellent wear resistance by preventing all the parts of the product is heat-treated uniformly peeling phenomenon.

First step: deodorization and degreasing

First, a degreasing process is required for uniform heat treatment of the product.

The degreasing process is a process for removing grease on the surface of a machined product, using a dedicated jig to align the product and degreasing it using T.C.E. The dedicated jig used in the degreasing process is important because the product is small in size and aligned by maintaining a constant interval.

Second Process: Preheating Process

And preheating process for 1-1.5 hours is carried out in the preheating furnace of 300-350 degreeC which is most suitable for nitriding operation.

Third Process: Nitriding Process

Afterwards, nitriding is carried out using air for 40 minutes to 1 hour in a nitriding furnace at 570 ° C. In this process, CNO: 28 to 32% and CN: 2.5% or less to stabilize the nitride layer and prevent delamination. , CO3: 22.5% or less, the component layer of 10-20μ and Hv: 900-1200 can be obtained.

4th process: cooling process

After the nitriding operation as described above, the temperature is maintained at 200 ° C. or lower in the air for stabilization of the dimension in the prevention of peeling phenomenon, and then subjected to a cooling step of stirring and cooling with air in an alkali washing bath to prevent oxidation.

5th process: washing process

The product undergoes the cooling process is subjected to an air shortening process using a short ball of 0.2 ~ 0.5m / m in hot water in order to finely clean the corners and the like difficult to clean the product.

6th process: drying process

In order to remove moisture of the product which passed the washing process, it is sufficiently dried in an electric furnace of 150-180 ° C. for at least 1 hour.

7th step: Sanding process

The product sufficiently dried by the drying is a sanding operation which is a final surface treatment process.

In the sanding operation, glass sanding using glass of 100 to 170 mesh is applied for surface gloss and surface roughness of the product, and the glass sanding operation is performed in a closed space due to the characteristics of the glass fiber material. In order to prevent the safety of the product and the separation of the product, a cylindrical jig is embedded in an enclosed space and sanded by an air sprayer.

As described above, the present invention improves the quality of the product and maintains the production cost by maintaining the wear resistance and the appropriate surface hardness as a stable nitride layer through the heat treatment process, which has not been solved by the surface heat treatment method developed so far. It is an invention that presents a novel technology in the heat treatment manufacturing method of the valve and seat of stainless steel, such as to reduce the competitiveness.

Claims (3)

In the method of manufacturing heat treatment for valves and seats for automatic transmissions, which consist of a single working process, preheating process, nitriding process, cooling process, washing process, drying process, and sanding process, nitriding is carried out for 40 minutes to 1 hour in a 570 ° C nitriding furnace. Work to manage the chemical composition at CNO: 28 to 32%, CN: 2.5% or less, and CO3: 22.5% or less, so that the compound layer forms 10 to 20 mu and Hv: 900 to 1200. Heat treatment manufacturing method of transmission valve and seat. The method according to claim 1, wherein the nitrided product is cooled to 200 ° C. or lower in air and cooled by using an air in an alkali washing tank, and a short ball and air of 0.2 to 0.5 m / m in hot water are used. Heat treatment of valves and seats for automatic transmissions, characterized in that the cleaning process is carried out by washing with water, the drying process is sufficiently dried in an electric furnace at 150 to 180 ° C. for at least 1 hour, and the surface roughness is maintained by using a glass of 100 to 170 mesh. Manufacturing method. The method of claim 1, wherein the step of the automatic transmission sheet is inserted into the oil holes formed in the same parts in each part to maintain a constant spacing, and to maintain a constant spacing in a constant space, continuous repeating Method for producing heat treatment valves and seats for automatic transmission, characterized in that by using a special jig of the clothesline structure consisting of a single.