2. Development of portable combined intelligent automatic welding machine.
In recent years, domestic automobile manufacturers attach great importance to welding automation. For example, the automation rate of Jetta body welding workshop 13 production line introduced by FAW is over 80%. Each line is controlled by a computer (programmable controller PLC-3), which automatically completes the transmission and welding of workpieces. The robot adopts point-to-point sequential trajectory, and the welding automation level is high, which not only improves working conditions, improves product quality and productivity, but also reduces material consumption.
3. Developing computer and information technology
With the industrial application of computer and information technology, the traditional welding production has been transformed into "accurate quantification" manufacturing mode.
The robot welding process simulation technology based on virtual reality modeling provides three-dimensional information of workpiece, fixture and robot welding torch posture, and has been widely used in welding process planning, process parameter optimization and welding fixture design. It has important application value for speeding up the compilation of welding program, shortening the on-site debugging time and accurately obtaining the position information of welding process. At the same time, the simulation technology is also applied to the evaluation of weld quality and the prediction of stress and deformation after welding. In the new car design stage, the connection mode, fatigue performance and impact performance of various materials can be comprehensively considered, and the applicability of the joint can be evaluated through simulation.
The welding production process information system based on computer and information technology is of great significance to the quality analysis and optimization of automobile welding production process and the management and decision-making of enterprises.
In a word, the automobile industry will make greater progress by vigorously developing new welding technologies, new materials, new processes and new equipment with high efficiency and energy saving, and applying robot technology, light intelligent equipment and computer information technology.
Second, the application and development trend of welding materials
With the development of lightweight car body, lightweight car body materials and nonmetallic car body metal materials are inevitable trends. In the future, steel plate will still be the main material, but some composite materials will be widely used.
1. Galvanized steel plate
With the development of automobile industry, in order to improve the service life of automobile body and enhance the corrosion resistance of tank materials, galvanized steel plates have been widely used. At present, resistance spot welding is mainly used in automobile body manufacturing. Compared with uncoated steel plate, there are still some problems in the spot welding process of galvanized steel plate: zinc ring is formed before the molten zinc layer of steel plate, which leads to the decrease of welding current density; The burn on the surface of zinc layer pollutes the electrode and reduces its life. Zinc layer has low resistivity and low contact resistance; Welding spatter, cracks, air holes and other defects are easy to occur.
2. High strength steel plate
In order to realize automobile lightweight and improve automobile safety performance, the application of high-strength steel plate is increasing year by year. At present, the varieties of high-strength steel plates mainly include phosphorus-containing cold-rolled steel plates, bake-hardening cold-rolled steel plates and cold-rolled dual-phase steel plates.
(1) Phosphorus-containing high-strength cold-rolled steel sheet: high strength, good balance between strength and plasticity, good corrosion resistance and spot welding performance; Mainly used for side walls, doors, ceilings and trunk lids.
(2) Bake-hardened cold-rolled steel plate: This bake-hardened steel plate, abbreviated as BH steel plate, has a thin thickness and sufficient strength, and is one of the first choice materials for lightweight design of body outer panels.
(3) Cold-rolled dual-phase steel plate: mainly used for load-bearing parts requiring good tensile performance, such as door reinforcement plates and bumpers.
3. Aluminum alloy
Compared with automobile steel plate, aluminum alloy has the advantages of low density, high specific strength, corrosion resistance, good thermal stability, easy molding and recycling, and mature technology. Parts made of aluminum alloy are gradually used in automobile industry. However, aluminum alloy welding still has large linear expansion coefficient and large thermal stress.
And porosity is easy to appear, which reduces the strength of aluminum alloy welded joints.
4. Magnesium alloy
The density of magnesium is only 35% that of steel. It has high specific strength and stiffness, good damping, good thermal conductivity and good dimensional stability, so it has been widely used in automobile industry. At present, magnesium alloys are mainly used for automobile door casting. With the development of die casting technology, thin-walled magnesium alloy body parts with complex shapes can be manufactured, such as front/rear fenders, instrument panels, steering wheels and so on.
5. High strength fiber composites
In the late 1980s, composite body panels were widely used and popularized, such as hoods, fenders, doors and roofs, and even all-composite bodies appeared. As the exterior decoration of automobile body, composite materials are mature in design, manufacture and application, and have developed from exterior decoration to interior decoration and structural parts.
New materials and new processes complement each other. The automobile industry is developing new manufacturing methods and updating traditional processes, and the fuel tanks of various special vehicles, including tankers, are also constantly improving. According to the prediction of relevant parties, in the next 10 year, the automobile's own quality will be reduced by 20%, and besides using a large number of composite materials and light alloys, the body design mode will also undergo major changes.