Introduction to automobile forging parts

  As the basis of the automobile industry, there are many kinds of automobile parts, including casting parts, forging parts, stamping parts, injection parts, etc., from the production process, among which the automobile forgings manufactured by forging process are generally used to withstand the impact or alternating stress of the working environment, playing an important role in the automobile driving.

(1) Basic concept of forging

Forging refers to the process of making billet or ingot produce partial or total plastic deformation under the action of pressure equipment and tool (die), so as to obtain parts (or blank) of certain geometric size and shape and improve its performance.

Forging essence is the use of metal plastic deformation to change the shape and performance of metal blank and become qualified forgings processing process, its fundamental purpose is to use external load (impact load or static load) through the forging equipment to produce plastic deformation of metal blank, so as to obtain the required shape and size of the forgings, at the same time make the mechanical properties and internal organization of the forging meet certain technical requirements.

Metal materials after forging processing, shape, size stability is good, uniform organization, reasonable fiber structure, with outstanding comprehensive mechanical properties. The main bearing structure or secondary bearing structure parts of mechanical equipment are generally forged. Forgings are also widely used in various fields of national economy and national defense industry.

The main raw materials of forging are metal bar, ingot and so on. In the process of smelting, pouring and crystallization of these raw materials, defects such as pores, shrinkage pores and dendritic crystals will inevitably occur, so it is difficult for the casting process to produce parts (such as hub bearings, transmission spindles, gear rings, connecting rods, balls, etc.) that can withstand impact or alternating stress in the working environment. The microstructure and properties of metal bar or ingot can be improved effectively after forging. The plastic deformation and recrystallization of the metal make the coarse grain finer and obtain the dense metal structure, so as to improve the mechanical properties of the forging. In the mold design, if the correct control of the force direction and fiber structure direction of the parts, but also can improve the impact resistance of the forging.

(2) Forging process classification

According to the size and shape of the forging, the use of tooling structure and forging equipment, forging is mainly divided into free forging and die forging. Free forging refers to the forging process that uses simple universal tools or directly exerts external force on the blank between the upper and lower anvil of forging equipment to deform the blank and obtain the required geometry and internal quality. Free forging mainly produces small forging parts, and adopts forging equipment such as forging hammer and hydraulic press to process the blank. Die forging refers to the metal blank in a certain shape of the forging die bore compression deformation to obtain forging, die forging is generally used to produce small weight, large batch parts.

According to the temperature of the billet during processing, it can be divided into hot forging, warm forging and cold forging. Hot forging refers to the use of external forces at recrystallization temperature, resulting in deformation and plasticity of the material. Warm forging is the forging of metal at a suitable temperature below the recrystallization temperature. Cold forging refers to the pressure working of metal materials at room temperature. The application range of the three forming processes is different. Among them, hot forging is mainly used in hub and gear blank, steering knuckle, ball tie rod, high pressure common rail, crankshaft, connecting rod and so on. The forging process adopted by the company belongs to hot die forging process.

(3) Main characteristics of forging process

In the process of parts processing, forging technology has the advantages of high production efficiency, strong comprehensive performance of forging, so it is widely used in the key and core parts of automobile, equipment manufacturing and other fields. The forging process mainly has the following characteristics:

① Processing equipment professional

The forging production line has the characteristics of large investment and long construction cycle. According to the characteristics of forging materials, forging processing equipment must have high performance. Therefore, forging enterprises usually need to invest a lot of money to purchase professional design software, high precision CNC forging equipment, high uniformity heating equipment, high performance heat treatment equipment, CNC machining equipment and complete sets of physical and chemical testing equipment. To meet the requirements of different production processes and downstream customers.

② The processing technology is complex

The main function of forgings is to bear external force or transfer torque in the work, usually requires special process treatment to meet its required performance. The main production process of forging products includes blanking, heating, forging, heat treatment, machining, physical and chemical testing and other links. The processing process involves metallurgy, metal processing, heat treatment and mechanical design and manufacturing technology and other multi-disciplinary and multi-field technology, and the technology integration is high. In addition, forging products have the characteristics of typical varieties, specifications, customization, the structure of different products is different, the need for enterprises to have a large number of professional technical workers, accurate control of various technical parameters in the production process, in order to ensure product quality.

(4) Development overview of automobile forging parts

As a pillar industry of many countries, automobile industry has a large scale of parts industry, which is the key application field of forging process, especially hot die forging process. The main forgings produced by die forging process are automobile forgings. The output of automobile forgings accounts for more than 60% of the output of die forging each year. In recent years, the output of automobile forgings has maintained a stable development trend.

After many years of development, our country has established a relatively complete industrial chain system of automobile forging parts, and the gap between technical level and strong forging industry gradually narges. Along with the transformation of each industry of our national economy to the high quality development stage, mainly presents the following development trend:

① Forging raw materials from ordinary steel to non-ferrous metal development

The in-depth development of automobile lightweight and new energy vehicles has further expanded the application of new materials forgings, especially light alloy forging technology, and promoted the development and use of nonferrous metal forging, such as aluminum alloy, magnesium alloy and other nonferrous metal forging parts.

② The localization trend of key forgings is accelerating

Great progress has been made in scale and development of Chinese automobile forging parts, and important progress has been made in key parts, and the trend of domestic production is accelerating. Our country has developed the core parts of high pressure common rail system, such as high pressure common rail tube, plunger sleeve, oil nozzle, gasoline high pressure common rail system stainless steel oil rail series forging parts, success in the domestication.

(3) Gradually adopt automatic, digital and intelligent production

According to the statistics of China Forging Association, with the adoption of automation equipment, the overall quality of front-line operators has been greatly improved. The automatic production line makes the production line layout of forging enterprises more reasonable, close to the actual production demand, the labor environment and production conditions have been greatly improved.

Based on their own transformation and upgrading needs, with the support of relevant ministries and local governments, Chinese enterprises have carried out automation, digital, network upgrading of original factories and workshops, or established new digital workshops and smart factories. At present, the global manufacturing industry is undergoing a new round of reshuffle. For Chinese manufacturing industry, it will certainly promote the digital transformation of enterprises, in order to enhance enterprise risk resistance ability.

(4) The vigorous development of new energy vehicles promotes the innovation of forging technology

The rapid development of new energy vehicles shows a trend of accelerating popularity. Although new energy vehicles in the power system and internal combustion engine cars are completely different, but the vehicle driving requirements still need to meet the general requirements of the car, safety, performance and other aspects have not relaxed requirements. Therefore, new energy vehicles still have strong demand for forging auto parts with excellent performance. In order to balance automobile safety, performance and driving range, new energy vehicles have new demand for lightweight metal forgings, hollow steel forgings and other forgings that have good comprehensive mechanical properties and relatively light weight. It promotes the technological innovation of hollow steel forgings and non-ferrous metal forgings such as aluminum alloy and magnesium alloy.