Modern automobile production is a high-efficiency, environmentally-friendly, large-scale production of water. Induction heat treatment technology has many advantages such as high quality, high efficiency, energy saving, environmental protection, etc., meets the needs of modern automobile production, has been widely applied, and the technical level has been rapidly improved. International advanced induction hardening technology 1, the power supply Foreign IGBT, MOSFET and SIT all-solid-state transistor power supply technology is gradually matured, and has been commercialized and serialized. Currently, there are 1200kW, 50kHz; 50~100kHz, 30~600kW; 300kW, 80kHz; low frequency band has the trend of replacing thyristor power supply; Using a parallel oscillating circuit, the SIT uses a series resonant circuit with a power of up to 1000 kW, a frequency of 200 kHz, and 400 kW, 400 kHz. They are ideal replacements for tube-type high-frequency power supplies. When the output power is the same as that of the tube power supply, the power saving is 35% to 40%, the installation area is saved by 50%, and the cooling water is saved by 40% to 50%. With the advancement of technology, MOSFETs are expected to replace SIT in the field of high frequency induction hardening. 2, quenching machine Induction hardening machines are becoming more automated, CNC control is increasing, and machine tools for automatic sorting of parts and automatic identification of incoming parts are increasing. (1) Universal quenching machine The universal quenching machine is developed in the direction of flexibility. A quenching machine can inductively quench the different parts with different performance requirements. A crankshaft quenching machine developed by Germany, the flanged induction hardening flexible machining system is slightly adjusted to handle similar workpieces of different sizes; for shaft parts within a certain diameter range (such as 30mm) and lengths of 300 to 800 mm, For shaft parts with similar quenching requirements, the quenching machine can automatically program 14 programs to automatically identify the incoming parts; Robotron.Eiotherm recently introduced a twin-spindle vertical quenching machine for quenching and tempering the workpiece in a compact process unit. It can handle wheel axles, three-slot sleeves and other universal joint parts. It only takes 2~5min to convert workpieces. It can be programmed by computer. According to the workpiece number, the relevant process data can be adjusted within 2 minutes. The GH company numerical control quenching equipment introduced by FAW High versatility, automation, multi-stage variable power shifting on complex parts, easy programming and easy operation. Figure 1 shows the CNC hardening machine from GH. (2) Special hardening machine The special quenching machine is more specialized, using Mechanical Parts and lower parts, heating, quenching, tempering, straightening, and inspection are completely automatic. Advanced computer control technology can monitor and display the quenching process and process parameters, track all operating procedures, and if the fault is found or the process parameters deviate from the given value, the unqualified parts will be automatically corrected or automatically listed, and the control system will be suspended and alarmed. At the same time, the nature of the fault and the action to be corrected are displayed on the screen. More advanced control systems also accommodate fluctuations in the chemical composition of the material and automatically adjust the specific power or heating time to ensure the quality of the induction hardened parts. For example, the horizontal half-axis quenching machine of the Kawasaki Plant of Japan High Frequency Co., Ltd., the upper tail plant can simultaneously quench three half shafts, and the Gunma plant can simultaneously quench two half shafts. The machine tool is actually an induction heat treatment production line. The fluorescent flaw detection inspection requires one worker, and the rest are automatically carried out. (3) Application of robot A vertical universal quenching machine manufactured by Japan High Frequency Co., Ltd. is equipped with a robot. The robot scans a two-inch sensor in sequence to make a plastic plate discolor. Although the power supply is only 3 kW, it is also The application trend of robots in induction heat treatment can be seen. (4) Mechatronics The power supply, the quenching machine and the cooling system are combined into a complete set, which has the advantages of small footprint, high production efficiency, and easy installation and commissioning. The crankshaft fixed heating and quenching device recently introduced abroad is only 1/4 of the combined complete plant. 3, quenching process (1) Static crankshaft induction hardening The first two units using the new technology of static crankshaft induction hardening have been used in Ford's V6 and V8 crankshaft quenching and tempering processes, showing a good market prospect. Its characteristics are: short heating time, generally only 1.5 ~ 4s, traditional process is 7 ~ 12s; high electrical efficiency, low cost; allow a large gap between the inductor and the workpiece, easy to adjust; easy to operate, good repeatability Easy to maintain; small footprint, only about 20% of the original. (2) Low hardenability steel gear quenching At present, many automobile factories in Russia use low-hardenability steel for integral induction heating surface quenching. They have been widely used in automobiles, tractor rear axle gears, excavator gears, transmission cross shafts, rolling bearings for train cars, automobile leaf springs, railway coil springs. Etc., achieved greater economic benefits. (3) Dual frequency induction heating quenching Foreign dual-frequency quenching is mainly used for gears. In the 1990s, the United States used a 10 kHz intermediate frequency and a 150 kHz high-frequency power supply to first heat the gear in the intermediate frequency inductor, then quickly drop it into the high-frequency inductor to heat it, and finally fall into the oil to quench. In the 21st century, this process has made new progress. For example, GH Company adopts the power electronic switch frequency to make the heating of the gear tip and the heel of the gear more uniform, which better guarantees the quenching quality of the gear. Current Status of Induction Heat Treatment Technology Applied in China's Automobile Industry 1, the power supply Power supply is one of the key equipments for induction heating. With the development of induction heating technology, it has experienced three development stages of mechanical intermediate frequency generator set and vacuum tube type high frequency power supply, thyristor intermediate frequency power supply and full transistor power supply. In the late 1980s, in industrialized countries, thyristor intermediate frequency power supplies have completely replaced the intermediate frequency generator sets, and China has gradually replaced them since the mid-1990s. Compared with the mechanical IF generator set, the thyristor (SCR) IF power supply has the following advantages: small size, light weight, low material consumption, high electrical efficiency, almost no power consumption when the inverter stops, and the inverter efficiency can reach over 90%. No mechanical movement, low noise, reliable operation, easy load matching, can determine the frequency of the power supply according to the load situation; start and stop is convenient, the frequency can be automatically tracked to maintain the best operating state; product design is simple, manufacturing cycle is short; easy to install, No special foundation is required; maintenance is convenient. The common feature of China's thyristor intermediate frequency power supply is that the degree of digitization of the fully integrated control circuit is higher than 90%, and the startup success rate is almost 100%. In addition to the conventional water pressure shortage, fast melting, overcurrent, overvoltage and other protection functions. It also has protection functions such as current limiting and voltage limiting, and the thyristor power supply with complete functions is also equipped with optional functions such as inverter failure and water temperature monitoring. The frequency can be up to 8 kHz, and the rated power can be 1000 kW or so. If the process is further improved, it can be close to the world advanced level. With the advancement of technology and tracking the level of international induction heating technology in the 1980s, China developed the first 50kW/50kHz IGBT current-type super-audio induction heating power supply with high electrical efficiency in the mid-1990s (Figure 2). At present, the frequency can reach 0.4 to 50 kHz, the maximum power can reach 800 kW, and the power reaches 100 kW when the frequency reaches 100 kHz. In the same period of IGBT application, China has successfully developed a 20 kW/300 kHz MOSFET high-frequency power supply, which narrows the gap with the international advanced level. With the advent of high-power MOSFET devices, high-power transistor high-frequency power sources are expected to be used in induction hardening during the year. . 2, quenching process With the rapid development of the automobile industry, the types and varieties of parts that are induction hardened in China are increasing. At present, China's automotive parts induction hardening materials include: 45 #, 40Cr, 55MnVS, 40MnB, 42CrMo, 35#, ZG45, ductile iron, alloy cast iron and so on. The induction heating quenching medium includes: water, polyvinyl alcohol, polystyrene water-soluble quenching medium, UCON, Howeton 251 and the like. The heating method and application mainly include: static magnetic field static heating once quenching (pin shaft parts, camshaft); transverse magnetic field continuous heating quenching (damper rod, shifting fork shaft, torsion bar, etc.); transverse magnetic field continuous Heating quenching (starter shaft, air compressor shaft, etc.); longitudinal magnetic field as a whole heating quenching (half-axis, etc.); profiled inductor parts rotating heating quenching (ball head pin); induction contact heating quenching (steering rack); Primary and continuous heating quenching of inner bore (output flange, bell shell inner cavity); rotary heating quenching of stepped shaft parts (small red flag rear hub shaft, steering knuckle); primary and continuous heating quenching of plane parts (steel plate Spring lateral limit plate); one-time and continuous heating quenching of thin-walled complex parts (front hub, sliding shaft fork); primary heating quenching of complex shaped parts (bell-shaped shell variable section shaft); notch once quenching (shift fork) The complex return line workpiece is rotated once and heated and quenched (crankshaft). 3, quenching machine In order to adapt to the Mass Production of various varieties, in the automobile production application, the types of induction hardening machine tools introduced in China are gradually developed from traditional special equipment to general equipment with high degree of flexibility and special quenching automatic production line. In the general quenching machine, the horizontal CNC quenching machine developed by FAW Technology Center uses the AC servo motor to drive, the moving speed is stable and uniform, the positioning is accurate, and the repeating precision is high; the part rotation adopts frequency conversion speed regulation, which can adapt to various process requirements. Using energy and numerical control technology to inductively quench the different parts with different performance requirements, and even realize multi-stage variable power shifting on the same part, the programming is easy and operability. For special quenching machine tools, after two years of hard work, Erqi and Tianshu Electromechanical Technology Co., Ltd. have overcome difficulties, using power pulse distribution technology, tailstock free-top technology, thin quenching transformer technology, independent suspension technology, suspension balance technology, etc. The successful crankshaft automatic quenching machine tool, and the power supply and water cooling system form a complete set of quenching equipment for the crankshaft of the internal combustion engine of the vehicle. The rounding of the shaft diameter and the shaft diameter quenching, the shaft diameter quenching and self-tempering, using computer control, through the display screen to the equipment The heating and quenching process parameters such as voltage, current, frequency, time, pressure, flow temperature, etc. are monitored and displayed, and many of them are currently used in China. These machine tools mainly use mechanical transmission in the transmission system. The advanced technologies such as ball screw and linear guide for modern mechanical transmission technology are widely used. The main drive adopts servo numerical control and frequency conversion speed regulation, and the moving speed is stable and uniform; the carriage is positioned accurately. The repeating precision is high; the workpiece rotation adopts frequency conversion speed regulation instead of fixed speed, which can adapt to various process requirements; the loading and unloading system adopts advanced step chain drive, tray feeding and manual feeding. In addition, in one production line, the high-power power source is used for quenching, and then tempered with lower power. The two processes are automatically completed on one production line, which reduces the process of repeating the upper and lower workpieces, reduces labor intensity, and improves production efficiency. 4, other devices and cooling system In the pneumatic and contactor type power switch, electric heating capacitor, quenching transformer, action sequence control and display, transformer three-dimensional mobile quick-change joints, etc., China has also made many technological advancements, so that the quenching technology and process level are continuously improved. For the cooling and quenching water circulation device, based on the latest technology of water cooling system of international induction heating equipment, China has developed a new type of high-efficiency, low-cost soft water cooler and water-water cooler suitable for China's national conditions. The high efficiency greatly improves the reliability of the heating equipment and prolongs the service life of the equipment. Recognize the gap and forge ahead Although China's induction hardening technology has developed rapidly in recent years, compared with industrial developed countries, there is still a considerable gap. MOSFET high-frequency power supply is the first choice of industrial developed countries, and China is still dominated by thyristor AC voltage regulation, high-voltage silicon reactor rectification, and energy-saving tube oscillator power supply in high frequency range; IGBT super audio power supply partially replaces thyristor intermediate frequency power supply. Trends, and China's application in this area is not popular enough; although thyristor IF power supply applications are more common in recent years, due to the limitations of the old enterprise transformation, some intermediate frequencies remain in the generator set. It must be pointed out that although China can produce MOSFET, IGBT and SIT induction heating hardening power supplies, the varieties and specifications are not as much and so fine as foreign countries. Since the key main power electronic devices cannot be produced domestically, they must be imported, so from the performance and technical level. There is still a considerable gap between the two countries. In general, compared with industrial developed countries, China's CNC and fully automatic quenching machine tool development is in its infancy. At the level of automation, most of the domestic equipment is manually loaded and unloaded, and the degree of automation is low; although the energy monitoring has application, the technology is not mature enough; the FUNAC and SIMENS servo systems have applications, but most of them are point linear motion, which is simple. The multi-axis linkage type CNC system has not been applied yet. In addition, the application of computer control technology in induction heating quenching is far less mature than that in foreign countries, such as automatic identification of incoming parts, automatic rejection of unqualified parts, process parameter tracking and deviation from setpoint correction. There are also considerable gaps in sensor manufacturing technology, sensor quick change, magnetizing material and utilization, cooling water circulation system, and quenching medium research and application. In view of these gaps, China should take active actions to establish a strict introduction and digestion policy, avoid repeated introductions, eliminate power supplies with severe energy consumption within a time limit, concentrate on developing shortages of components, improve the quality of quenching machine tools, and enable induction heating technology to quickly catch up with the world's advanced Level. 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