关于机械论问翻译(英文版)

Automobile manufacturers welding application of new technologies with the overall development trend Welding is a modern mechanical manufacturing process a necessary way to get car manufacturers at a wide range of applications. Automobile engine, gearbox, axle, frame, body, inside the six can not be separated from the total Chengdu welding techniques. At the manufacture of automotive components, spot welding, projection welding, seam welding, roll welding, arc welding electrodes, CO2 gas shielded arc welding, argon arc welding, gas welding, brazing, friction welding, electron beam welding and laser welding, etc. types of welding methods, because of spot welding, gas shielded arc welding, brazing with the production volume is very large, a high degree of automation, high-speed, low power, welding deformation of small, easy-to-use features, so the coverage of auto body sheet metal parts is particularly suitable, so , in automobile production in the most widely used. Investment costs at about 75% in spot welding, other welding methods account for only 25%. With the development of the automobile industry, auto-body welding production line is also gradually develop in the direction to the fully automated, in order to catch up with international standards, improve productivity at the same time, requires efforts to improve the quality of automobile manufacturers. As we all know, implementation is a prerequisite for automated manufacture of parts and components to high precision, the smallest hope of welding distortion, welding sites want fresh appearance, and called for more and more high-welding technology. Facing our countrys accession to WTO opportunities and challenges, welding area of the popularization and application of new technologies for the automotive industry to enhance the brand has an extremely important role.First, the auto industry used welding methods and the application of parts andcomponents Automotive applications are welding industry noodle one of the most widely used method of welding a wide range of applications as follows: 1. Resistance Welding (1) Spot welding used mainly for body assembly, flooring, doors, side Wai Wai after, the former bridge and small parts. (2) Multi-spot welding for body baseboard containing boxcar doors, engine cover and trunk cover. (3) Projection welding and roll welding for body parts, shock absorber stem, brake shoe, screws, nuts and small, such as stents. (4) Seam welding the body cap for rain canopies, shock absorber head, fuel tank, muffler and oil, such as disk. (5) For butt welding steel, was discharged into the air stem, cutting tools, etc. 2. Electric arc welding (1) CO2 arc welding for the car, rear axle, frame, shock absorber stem, beam, shell and tube rear axle, drive shaft, hydraulic cylinders and jacks, such as welding. (2) Welding for the oil plate, aluminum alloy parts for welding and repair welding. (3) Electric arc welding electrode for thick parts such as stents, spare tire racks, trailers and so on. (4) Submerged for half-bridge casing, flange, and natural gas vehicles, such as pressure vessels. 3. Special welding (1) Friction welding for automotive stem, rear axle, axle, steering rod and the attendant tools. (2) For electron beam welding gear, after the bridges. (3) Laser Welding for Body backplanes, gear, materials and spare parts under the edge and so on. 4. Oxyacetylene welding Repair welding for body assembly. 5. Brazing For radiators, copper and steel parts, hard alloy welding.Two, the automobile industry welding application of new technologies Nowadays, the automobile industry a lot of advanced welding technology, only to set out the relevant body welding and welding of new technologies. 1. Resistance and control of energy-saving technology (1) Conjoined hanging spot welding in the automotive industry the most widely used are hanging spot welding machine, a workshop is often dozens or hundreds of units, mostly in its capacity above 100kVA, automotive sheet metal at the welding has been widely applications. (2) Of resistance welding machine current resistance welding machine communicate substantial use of the single-phase AC 50Hz power supply, large capacity, low power factor. The development of three-phase low-frequency resistance welding machine, three-phase secondary rectification welding contacts (in ordinary type spot welder, seam welder, welding machine application convex) and the IGBT inverter resistance welding machine, you can solve the imbalance and improve power grid power factor (up to 0 9 above) the problem. At the same time can be further save power, the realization of microcomputer control parameters can be better applied to welding of aluminum alloy, stainless steel and other difficult to weld metal welding. It could also further reduce the equipment weight. (3) The control of resistance against the Southwest Jiaotong University 1 Rim Factory Alloy Rim Butt Welding development of PLC (programmable controller) Intelligent controller, on the original machine had a transformation, to solve the aluminum alloy car lap welding quality problems, improve welding productivity. Factory has been developed after the same seam welding PLC controller to solve the general clean-up requirements parts of the seam welding problem. These two controllers through the development, proved more than single-chip microprocessor controller PLC anti-interference ability, high reliability; IPC controller than small size, low cost, use of a common single-phase AC power frequency resistance welding machine achieve a high degree of difficulty of the butt welding and seam welding job. 2. Gas shielded welding technology (1) The surface tension of the transition waveform control method, the key is to use two current pulse achieve a droplet transition, the first current pulse to form a droplet and up until a short circuit droplet and the workpiece; No. 2 current pulse is a short-term narrow pulse and continuous detection of its di / dt, at the same time to control the value of current pulse to generate the appropriate electromagnetic contractile force, so that droplet contraction thin neck, and finally by the pool surface tension pull off, finish a droplet transfer without spatter. (2) Inverter power inverter power source waveform to control the use of dynamic characteristics of a good and flexible controllability, the use of waveform control, in the short-circuit current increased by inhibiting the early stages to reduce the electromagnetic force when the little bridge in the newly formed droplet transfer obstacles and blasting off to reduce the large particles flying, and in favor of droplet spread in the pool; when droplet spread out in the pool after making a rapid increase in current in order to speed up the formation of necking later slow rise to a lower peak so that when the little bridge blasting off to reduce spatter. (3) TIG welding of new technologies have a very non-melting (TIG) and MIG (MIG) two non-ferrous metals are used in the automotive industry and high-alloy steel welding. In order to improve the CO2 gas shielded arc welding spatter forming and reduce the use of add 80% or 20% Ar mixed gas shielded arc welding. 3. High-energy beam welding and heat processing technology High-energy beam source is the energy density has been greater than 5 108W/m2 of the heat source (electron beam, ion beam and laser), is used in automobile industry, is currently abroad, the development of new technologies have: (1) Laser and arc welding composite heating laser welding can be a narrow and deep weld seam, welding the electric arc welding can be wide and shallow weld; the former investment, the latter low-cost combination of both characteristics, will greatly enhance welding efficiency. Composite heating laser and arc welding torch design is particularly important, the two sources of heat to the angle as small as possible, the torch is also designed to power laser + double arc. This method has been at 4 8mm thick steel structures used, is intended to be used in thinner aluminum alloy automobile parts production and welding. In addition to laser welding and precision cutting application, but also the formation of friction surface reservoir fine patterns or remelting composite layer to enhance wear resistance applications. (2) The application of plasma argon plasma welding protection already cutting applications in different sectors, mainly for steel and non-ferrous metal processing. At present, air plasma cutting has generally been applied to general steel and non-ferrous metal cutting, domestic rail passenger car plant to introduce the underwater plasma cutting, so as to reduce distortion and improve accuracy. Engine valve body is already being used in plasma-filled lap welding. Over the last decade plasma powder surfacing there is great development, it can conduct small-fusion fine material than the thin-layer surfacing, surfacing to a variety of special alloy surface.Three, the automobile industry in the development of new welding materials trends With the development of increasingly compact cars smaller and lighter, the application of new materials to make car material composition of the apparent changes happen, the future of car body material is still the main plate, in order for the plate thickness thinning will be widely used in high strength steel . At the same time in order to enhance the bodys anti-corrosion, the world on a number of car manufacturers in car production in substantial use of galvanized steel sheet. In addition, the use of aluminum alloy, plastic and ceramic materials. According to the experts predict that the end of this century will not be at high-volume production cars appeared in aluminum or plastic body body. 1. Galvanized steel plate American Welding Society at chapter meetings to discuss the automobile industry on the application of metal plates welded problem, the relevant experts have pointed out that welding galvanized steel sheet most promising method is laser welding. However, because of the degree of automation of the process is now not enough, we must improve the automobile industry widely used method of contact spot welding. The main disadvantage of this method are Weldment at electrode contacts with substantial transition of zinc electrode burn faster. It is suggested that the use of Al2O3 particle dispersion strengthened Cu-Zn and Cu-Cr alloy electrode can be at a minimum under the electric resistance welding, in order to guarantee access to the smallest size welded joints. 2. High-strength steel plate In order to realize lightweight cars, improve vehicle safety performance, high strength steel in the automotive application is increasing year by year, the current emergence of a new generation of high strength steel materials - ultra-fine grained steel. The steel major means to further enhance economic indicators, based on iron and steel materials, strength, toughness than the existing steel doubled. A new generation of ultra-fine grained steel at the organizational structure with ultra-fine grain, high purity and high uniformity of properties. Currently used to study a new generation of ultra-fine grained steel major has 400MPa and 800MPa grade two level. At a new generation of research on iron and steel, our country and the international level and there is no gap, almost simultaneously started, with Japan and South Korea between the two countries living side by side the worlds leading position. However, due to appear shorter, so the unit participated in the study is not much, and is based on Iron & Steel Research Institute and the Department of Mechanical Engineering, Tsinghua University-based. In the ultra-fine grained steel welding technology for the study must have achieved a number of advanced results. 3. Aluminum Alloy Aluminum alloy with light weight, high strength and corrosion resistance, etc., are good building materials, automobile industry is gradually Materials in the use of aluminum alloy parts. Aluminum alloy welding has five main features: (1) Aluminum alloy surface has a layer of dense oxide film (melting point of about 2050 ), welding if the latter fails to clear, it will affect the quality of basic metals melting, forming a mixture of such quality issues. (2) Thermal conductivity of large (approximately 4 times that of steel), electrical conductivity, and welding and steel to achieve the same welding speed, the welding heat input than when welding steel large 2 4 times. (3) Coefficient of linear expansion, and there is Weldment have a greater thermal stress, deformation and the tendency to crack. (4) Stomatal easily. (5) Aluminum alloy to reduce the strength of welded joints. Aluminum alloy welding of these characteristics, it is in the development of our welding equipment and welding technology should be taken seriously the problem, the only way to develop a suitable aluminum alloy welding equipment, materials and welding technology.Four, the automobile industrys general trend of development of welding 1. The development of flexible automated production systems Taking an overall view of the welding automotive industry status quo, it is not difficult to analyze the development trend of the automotive industry for welding: the development of flexible automated production systems. And industrial robots, automated production because of set production features and flexibility all in one, so large-scale car production in recent years, the rapid use of the robot. In welding, the main use is to spot welding robot and welding robot. Welding want highly automated production line, widely used in the 6-DOF robot and welding robot with forceps repository can be made under different welding parts welding product requirements or changes from the repository automatically grasping forceps for welding required. Transmission devices have been developed into a more flexible use of unmanned sensors and car-oriented. 2. The development of lightweight modular intelligent automatic welding machine The level of the domestic automobile welding gap compared with foreign countries. In recent years, the domestic automobile factory attaches great importance to the automation of welding. Such as the introduction of the Jetta FAW body welding workshop 13 production line automation rate of more than 80%. Each line by computer (programmab