Magnesium alloy materials are the lightest metal engineering structural materials today. Using them to manufacture automobiles, especially new energy electric vehicle components, can achieve significant energy saving and emission reduction effects. Now industrialized developed countries are moving towards using as many lightweight materials as possible to manufacture automotive parts. Widget goals go forward.
In 2019, the average magnesium consumption of automobiles in North America, Europe, Japan, and South Korea has reached about 68 kg / vehicles, and it may exceed 105 kg / vehicles in 2030. The average magnesium consumption of automobiles in China in 2019 is only about 18 kg / vehicles, and The gap between developed countries is too large. The commissioning of Shanghai Tesla Motors will definitely promote the application of magnesium in Chinese cars.
New energy electric vehicles, the development of lightweight is an inevitable trend, as much as possible to make automotive parts with lightweight materials, is the best measure to reduce the net weight of vehicles, aluminum and magnesium are the most desirable lightweight materials, aluminum density is 2.70 g / cm3, while the density of magnesium is only 1.74g / cm3. Therefore, the weight reduction effect of magnesium is greater than that of aluminum, and magnesium and magnesium alloys have become one of the best materials for electric vehicles.
Advantages of using magnesium alloy to manufacture electric vehicle parts: significantly reduce the net weight of the car, reduce power consumption, reduce greenhouse gas emissions; improve the integration of parts, reduce the processing and manufacturing and assembly costs of parts; large design flexibility, good formability The magnesium alloy can improve the shock resistance and crash resistance of the car; improve the stiffness of the car; increase the recycling rate of used parts; improve the safety performance and operability of the car. For every 10% weight reduction, a car can save about 5.6% of fuel, and correspondingly reduce greenhouse gas emissions. Compared with the performance of magnesium and other commonly used structural materials, magnesium alloy is an excellent material for manufacturing transportation equipment such as automobiles and motorcycles. It can not only reduce the net mass and energy consumption of vehicles, improve the acceleration and braking performance of the entire vehicle, but also Significantly reduce driving vibration and noise, improve driving and passenger comfort. The application of magnesium alloys in automobiles is mainly die castings and castings, especially die castings. At present, more than 75% of die castings are used in automobile and motorcycle manufacturing.
Automotive parts that can be made from magnesium alloy materials
The earliest use of automobiles was cast magnesium alloys. The application of magnesium alloys in automobiles has a history of 100 years. As early as 1921, the Ford Motor Company in the United States cast magnesium pistons. It was not used, but the horn discs and the wheel center and truck wheels of the coal mining truck were successfully made from sheet metal later.
In the 1930s, the crankcase, transfer case, vane cover and engine bracket of Volkawagen Beetle, a German Volkswagen company, were made of magnesium alloy, with a total weight of 17kg, which was 5kg less than that of cast iron. This type of shock absorption is particularly important for cars with engines at the rear, which can greatly improve the stability of the car. Biter vehicles have produced 19 million vehicles and used about 400kt of magnesium alloy.
In the 1930s, automotive parts using magnesium alloys were crankcases, oil pumps, engine mounts and bodies, distributors and magnet housings, headlamp brackets, fan blades, cam curved covers, oil filters, clutch housings, Oil pan, transmission. More magnesium-alloy auto parts appeared in the 1960s and 1970s: control panels, oil pump gearboxes, clutch and transmission box housings, wheels, tank covers, distributor mounts, oil filter mounts, and fuel power generation Engine ventilation valve body, oil pump horn tube, flat oil plug, six-cylinder crankcase, differential gearbox, carburetor, clutch box, window opening and closing adjustment guide rod, rocker sleeve.
In the 1980s, the application of magnesium alloy die castings in the world's automobiles continued to expand. Automobile parts made of magnesium alloys include: lever components, brake pulleys, vacuum cleaner housings, rocker covers, glove box frames, transmission handles, and engine blades. , Cylinder block cover, valve body, fan, blade, intake manifold, lamp frame, suction grille, front wheel active cover, four-wheel transfer box, partition frame for freezer blade, viscous blade transmission, brake and Clutch pedal.
After entering the 1990s, its compound annual growth rate reached 15%, and the fastest growth rates were in North America, Western Europe and Japan. At present, more than 70 parts of automobiles are made of magnesium alloys, more than 90% of which are die-casting parts, and the most commonly used are the instrument panel base, seat frame, steering wheel shaft, engine valve cover, transmission case, engine Air manifold, body and wheels.
Dashboard base
The requirements of the instrument base for manufacturing materials: good deformation performance, light weight, high dimensional accuracy, simplified parts structure, etc., magnesium alloys can meet these requirements.
In the 1980s, Volkswagen took the lead in casting the instrument panel base from Mg-Al-Zn series alloy (AM series), which is used for Audi V8. It is an integral die-casting part with a length of 1440mm, a wall thickness of 3.5mm, and a quality About 4.3kg, compared with steel parts, the weight is reduced by about 65%, and the structure is greatly simplified. It integrates the base that used to be assembled with 30 to 60 parts into a whole. This one-piece base can provide support structure for "A" type pillars, HVAC (heating ventilation and air conditioning) controllers, airbag boxes, air conditioner lines, steering rods, brakes, clutch pedals and other components. Added beams and speedometer, radio and glove box bracket. AM-based magnesium alloys have good formability, with an elongation of about 6%, and their parts only deform and are not easily broken when impacted. The dashboard base used by General Motors (GM) G-Van weighs 15kg and is probably the largest currently used. In addition, some cars such as Mercedes, Chrysler, Fiat and other companies use magnesium alloy monolithic instrument panel base (dashboard).
Seat frame
Automobile and high-speed rail seat frames are another typical part that can be die-casted with magnesium alloys. Because magnesium alloys have the characteristics of good formability, low density, and good simplified structure, they also have the advantages of easy integration of parts and improved shock resistance. Fiat Motors has die cast Alfa Romeo Meridian MPI seat frames from AM60 alloy.
German Mercedes Motor Company uses AM series magnesium alloy die-cast seat frame, which is assembled by 5 pieces of magnesium alloy thick-wall die-casting parts, weighs only 8.5kg, which is 11.5kg lighter than the original steel frame, that is, 57.5% In the future, a seat frame of only 2kg was successfully developed, which consists of a seat bottom frame and a seat back frame. Their wall thickness is 2mm ~ 4mm, and no mechanical cutting deep processing is required before assembly. The seat frame of TGV high-speed train in France is die-cast from AM series magnesium alloy. The total mass of foam plastic and textile is 14kg, which is 50% lighter than steel frame. Ford Motor Company in the United States replaced the steel bracket with an AM60 magnesium alloy seat bracket on a minivan, reducing the mass from 4kg to 1kg. The application of magnesium alloy seat frames has greatly stimulated the development of magnesium applications. Replacing steel and aluminum with magnesium can achieve significant weight reduction effects, energy saving and emission reduction, and improve the car's impact resistance.
Driving system
The airbag is added to the driving system to increase its mass, which affects the maneuverability of the car. If some parts are made of magnesium alloy, it can significantly reduce the quality and improve the driving performance of the car. Toyota Motor Corp. of Japan uses AM60 magnesium alloy die-casting steering wheel, its core is die-casting AM50 alloy, and other parts are AZ91 alloy. The quality of the entire steering wheel is reduced by more than 45%. Magnesium alloy has the advantages of light weight, good operation performance and reasonable price. Ford Motor Company's die-cast integrated magnesium alloy steering rod is composed of 3 parts and is die-cast with AM series alloy, with a total mass of 1.2kg. Audi uses AZ91D (Mg-Al-Zn series alloy) to die-cast the rod support of the Zitzmannt, which is about 20kg lighter than steel.
Engine bonnet
Automotive engine bonnets can be made of aluminum, magnesium, steel, plastic, etc. However, the major automotive companies currently use more magnesium alloy die-casting, which is the mainstream and development trend. Mercedes-Benz Automotive Corporation (Mercedes-Benz) The valve cover of automobile engine die-casting with AM60B alloy is only 3.2kg, which is about 4kg lighter than the steel cover. Its main advantages are: light weight and large benefits; it can be die-casted at one time, and the deep processing cost is greatly reduced; oil leakage is prevented, creep resistance is high, and it is durable.
Intake manifold and engine bracket
In the early 1990's, General Motors of the United States used magnesium alloy to manufacture the intake manifold of the engine. The weight of the manifold box was 2.7 kg, and the weight of the cover was 0.9 kg. Pierburg, Germany, has developed several magnesium alloy intake manifold systems for Mercedes Benz Motors. Due to the use of magnesium alloy intake manifolds in Mercedes Benz 3.2L V6 engines, they were World (Wards Auto World) named the lightest V6 engine in the world. The engine mount is also a main part that can be die-casted with magnesium alloy, which has obvious weight reduction and shock absorption effects, and has been widely used.
Wheels and other parts
Wheels and knee pad reinforced versions can also be die cast with AM60 magnesium alloy. In 1976, Toyota Motor Corporation of Japan used magnesium alloy die cast wheels and knee pad strengthen plates. In 1994, the General Motors Oldsmobile98 and Park (Buick) Avenue used two types of magnesium alloy knee pads, with a size of 300mm × 1470mm, an average wall thickness of about 2mm, and a weight of 1.8kg. The second-generation magnesium alloy wheels die-cast by Fiat Motors in Italy weigh only 5.4kg and are 28% lighter than aluminum alloys.
Ford Motor Company, General Motors, Chrysler Motors used 30, 45, and 20 magnesium alloy die-castings in each vehicle in 2004. The quality of the 2000 version of the CP launched by Sweden's Volvo Car Company earlier Although it is only 700kg, the amount of magnesium alloy workpieces is as high as 50kg, and the rate of magnesium formation is as high as 7.14%.
Prediction of the application of magnesium alloys in automobiles Due to the urgent requirements of energy conservation and emission reduction, the automotive industry is under tremendous pressure, especially in Europe, which has also adopted legislative measures to limit automobile fuel consumption. Auto manufacturing companies have produced new energy electric vehicles. China has become a global The large-scale producers and front-runners of electric vehicles, the commissioning of Shanghai Tesla Motors, has further strengthened the global position and competitive advantage of China's automobile industry. There is no doubt that this will stimulate the application of magnesium alloys in the automobile industry.
In the early 1920s, a survey conducted by the International Magnesium Association and Hydro Magnesium Marketing showed that in 1991, the application of die-cast magnesium alloys in the western countries in the automotive industry was only about 20 kt, and the amount of use increased in 2005. To about 170kt, it increased by 150kt in 2014, and increased by almost 10kt per year. In 1998, D. Magners and J. Wilkens predicted that the use of magnesium alloys in the automotive industry would continue to grow. Liu Yushi and Xie Xuhong determined in 1999 that the amount of magnesium used by the Chinese automobile industry was only 8.5 kg / vehicle, while the average amount of magnesium alloy used by foreign cars had reached 40 kg / vehicle. Someone in 2001 ("Light Alloy Processing Technology", 2001, 29 (11): 1) said: "Ford predicts that the average magnesium used per car in the world will reach 100 kg in 2020." In 2019, the total output of Chinese cars is about 25,000k, and the total global output is calculated as 50,000k. If this year's output is calculated based on this, for example, if 100kg of magnesium is used per car, the world's magnesium consumption can reach 5000kt. Impossible, because only 1100kt will be produced in 2019, so Ford's forecast is too optimistic. The author believes that the consumption of foreign cars in 2019 will be about 68kg / car, and it will reach 105kg / car in 2030. The average magnesium consumption of Chinese cars in 2019 is about 18kg / car, and in 2030 it can reach 28kg / car or more. If China's auto output could reach 34,000k this year, the total demand for magnesium would be 952kt.