The importance of tempering heat treatment for automobile forgings

With the development of modern industry, the automobile industry has become an important part of the national economy. The manufacturing level and technology of the automobile machinery parts have become one of the main bottlenecks restricting the development of the domestic automobile industry. As one of the main ways of automobile machinery parts manufacturing, automobile forgings is also one of the important parts of modern automobile technology. The study on the tempering process of automobile forgings can greatly improve the mechanical properties and service life of automobile forgings, and further promote the development of automobile industry.

 

In order to promote the development of automobile forgings industry, this paper aims to explore the tempering technology of automobile forgings, systematically expounding the basic principle of tempering and processing technology of automobile forgings.

 

Two, automobile forging quality control technology

 

Conditioning treatment means that in the process of heating, insulation and cooling of metal materials, the porosity of steel decreases, the hardness increases, and the strength, toughness, plasticity and other properties of materials are enhanced. Automobile forgings can meet the requirements of service life, mechanical properties and material cost of automobile body parts after conditioning treatment.

 

(1) Performance and defects of automobile forgings

 

1, the performance of automobile forging

 

Automobile forgings are one of the representatives of high quality and high performance materials. Steel forgings play an important role in automobile manufacturing. After forging, quenching, tempering and other processes of automobile forging manufacturing has high strength, high toughness, high plasticity and other superior performance, and in the automobile structure of small size, light weight, low density, can greatly reduce the weight of the automobile body, improve the quality of the automobile.

 

2. Defects of automobile forgings

 

However, in the process of automobile forging, it is difficult to avoid the appearance of some manufacturing defects due to the limitations of various technological parameters and production environment. These manufacturing defects may have a significant impact on the performance and service life of automobile forging.

 

(2) tempering principle of automobile forgings

 

Tempering is a commonly used process in steel processing. Its basic principle is that steel is first quenched and then tempered. The specific process is: by heating the steel, so that the grain expansion, in the holding time to reach, rapid cooling to make the steel to reach the state of supersaturation, the formation of martensitic structure. Then through tempering treatment to weaken the brittleness of steel, improve the toughness and plasticity of steel.

 

(3) Type of tempering process for automobile forgings

 

The tempering process of automobile forgings can be divided into gas furnace and electric furnace. With the rapid development of metallurgical industry, modern advanced technology and equipment can enable steel to reach more advanced performance levels. One of the most important equipment is the electric furnace.

 

(IV) tempering process of automobile forgings

 

The conditioning process of automobile forging mainly includes the following steps:

 

1. Preparation before heat treatment of automobile forgings

 

Before conditioning treatment, in addition to determining the parts that need to be conditioned treatment, it is necessary to make relevant preparations for the parts, such as parts cleaning, calibration and so on.

 

2. Heating of automobile forging parts

 

The heating process of automobile forging must be controlled in a certain temperature range, and the specific temperature range should be determined according to the actual situation. In the process of heating, the surface of the parts should be basically consistent with the temperature of the heating furnace to avoid thermal deformation and uneven temperature of the automobile forging.

 

3. Thermal insulation of automobile forgings

 

In the heating process of automobile forging, it is necessary to carry out thermal insulation treatment, the general time is 15-30 minutes. It should be noted that the insulation time of parts must be controlled within a certain range to avoid too long insulation time leading to grain increase, thus affecting the performance of parts.

 

4, automobile forging cooling treatment

 

Automobile forgings should be cooled after heat preservation treatment, which is generally treated by oil bubble quenching. During the treatment process, the cooling rate needs to be controlled to ensure the best quenching effect.

 

5, automobile forging tempering treatment

 

After quenching treatment of automobile forgings, the steel will show some brittleness and high hardness. Therefore, it is necessary to temper the automobile forging. Tempering temperature should be determined according to the actual situation, temperature control in the process of tempering is very important.

 

6, automobile forging ground treatment

 

After finishing the tempering treatment, it is also necessary to carry out ground treatment on the automobile forgings. Ground treatment refers to polishing and chrome plating on the surface of the parts to enhance the corrosion resistance and beauty of the automobile forgings.

 

(5) tempering process parameters of automobile forgings

 

The quenching and tempering process parameters of automobile forgings mainly include quenching and tempering temperature, tempering temperature, holding time, cooling speed, etc. These parameters have a very important impact on the performance of automobile forgings. Tempering temperature and tempering temperature are generally adjusted according to the organizational structure of the material, and the working temperature is generally between 500-650℃. Generally 15-30min is the best holding time, too long or too short will have adverse effects on finished materials. The cooling speed should be set according to the quenching hardness of the material.

 

(VI) Quality control process of automobile forgings

 

The quality control process of automobile forgings needs to ensure the accuracy of control parameters such as heating temperature, holding time, treatment time and temperature uniformity. At the same time, it is necessary to take effective measures to control the macro and micro organization of automobile forging, so as to ensure the quality and performance of parts.

 

(7) The phenomenon and countermeasures of poor quality control technology of automobile forging

 

In the process of conditioning automobile forging, due to various reasons, there are also easy to appear some undesirable phenomena, such as: surface cracks, deformation, intergranular corrosion, etc. In order to solve these problems, it is necessary to take corresponding countermeasures in time to ensure the normal use of automobile forging.