Enterprise Name: CHENGDA MODEL SET
Contact person: Business Department
Mobile phone: 198-5734-5006
Address: 39 Success Road, Jiashan Economic Development Zone, Zhejiang Province
Websit : en.chengda-mould.com
Cold forging is a process of forming products at room temperature to meet specific specifications, and then applying to products or specific product components. This process is called cold forging process. According to incomplete statistics, the history of forging development in foreign countries has been nearly 5000 years, and China has been from steel smelting to forging for nearly thousands of years. More and more diversified cold extrusion technology is applied in contemporary times.
The difference between cold forging and cold extrusion has been introduced in the previous chapter. First of all, they are different in terms of names and processes. Because of the differences in technology and materials, the application fields are also different.
The rapid development of automobile industry has provided the driving force for the development of cold forging technology. According to incomplete statistics, the weight of cold and warm precision forgings in each car reaches 45-50 kg. The rear axle drives the half axle, the cross axle in the universal joint, the straight bevel gear, spline, hub nut, the claw pole of automobile alternator, the constant speed universal joint parts of front drive car and synchronizer teeth. Rings and so on are typical cold forgings for automobiles. Fig. 1-1 is a precise forging part of Japanese car which was newly put into production every five years from 1960 to 1995, summarized by Professor Hideo Ito of Japan. In 1965, the precision forgings per vehicle were only about 6 kg, which had increased to 45 kg by 1995. Since the 1960s, the main production of small axisymmetric products (such as hub bolts) and larger forgings (such as steam pump rotors) began in the 1970s. In the 1980s, CVJ parts were important products. Since 1990, precision gears have become the main target products.
Modern cold forging technology began at the end of the 18th century, but it was not until the 1930s that the German invented the surface lubrication method of forming phosphate film on the workpiece surface that cold forging technology gradually became practical. In 1967, the International Cold Forging Group (ICFG) was founded and held its first plenary meeting in London, England, in 1968. ICFG holds a plenary meeting every year and publishes a large number of industry technical documents or standards, which plays an important role in promoting international academic exchanges and production of cold forging technology. At present, ICFG mainly works in the following areas:
(1) Tool life and tool quality of die manufacturer: Mainly study die material, surface treatment, friction and fatigue related to die life and die quality.
(2) Process simulation: The application of numerical simulation software, the reliability of input data, the progress of commercial software and the limitations of existing models are mainly studied.
(3) Properties of cold forged products: Mainly studies the residual stress, work hardening, dimensional accuracy, deformation, metallographic structure, machinability and lightweight design of cold forgings.
(4) Incremental bulk forming: This paper mainly studies numerical modeling, material testing, physical simulation, die wear, innovative applications related to incremental bulk forming.
China's cold forging technology started in the late 1950s, and in 1962 in Shanghai Jiaotong University successfully developed the first ferrous metal cold extrusion parts (shuttle sleeve). 1965-1975 was the first climax of industrial application of cold forging technology in China. It was mainly used in bicycle, sewing machine, truck and electronic industry. Special mechanical cold forging press was introduced from abroad. 1600-3000 kN mechanical cold forging press, 6300 kN hydraulic extruder and 2500 kN bidirectional automatic extruder were developed. At the same time, in terms of theoretical innovation, the theory of allowable deformation degree of cold extrusion of ferrous metals was put forward, which laid a foundation for the development of cold forging process in China. Figures 1-2 to 1-4 show that from 1960s to 1970s, some ferrous metals (including pure iron, carbon steel, low-alloy steel, stainless steel, high-speed steel, heat-resistant steel), copper and brass cold extruded parts, aluminum and aluminum alloy cold extruded parts) were completed in China.
Because the quantity of some products did not reach the economic batch, the cold forging technology in China failed to develop continuously in the late 1970s and turned into a low ebb. Since 1990s, with the rapid growth of car and motorcycle production in China, the cold forging market has been enlarged. Multi-station forming, warm (hot) cold composite forming, occlusive forging, back pressure forging, shunt forging and numerical simulation of cold and warm forging have been applied. However, there is still a big gap between China's cold forging technology and developed countries, and the development of cold forging technology has been strengthened. Promotion and application is an urgent task.
High-speed forging technology is especially suitable for mass production of spare parts because of its high production efficiency. High-speed cold forging machine has been widely used in foreign precision forging enterprises. For example, Coldmatic series cold upsetting forging machine of HATEBUR company in Switzerland adopts multi-station horizontal forging. The automatic feeding and high-speed shearing blanking system of manipulator clamp between workstations ensures the surface quality and precision of blank, and the workpiece of arbitrary shape and length can be well controlled by a single adjustable manipulator. The advantages of clamping and transferring to the next station at the right time are discussed. Precision blanking can be realized on Coldmatic AKP 4-6S equipment and the forming of pinion parts as shown in Fig. 1-14 can be completed through six working stations: 1. Precision blanking; 2. Forward extrusion of small diameter parts without material section shaping; 3. Forward extrusion of key groove parts; 4. End upsetting; _Reverse extrusion of small teeth parts (without turning parts); _shoulder diameter of concave die side. Reduce; _Final finishing of the small teeth. The production efficiency of this part can reach 160 pieces per minute.