中文  |  English  |  Home

Dongsheng
 

Automotive lightweight materials meet new challenges

Date:2016-08-05 15:35
  “2013 is the last year of the implementation period of automotive key lightweight technology development and integrated vehicle application projects. Some key technologies for vehicle lightweighting are expected to be promoted and applied.” Recently, the National Automobile Lightweight Technology Innovation Strategic Alliance was held. The National “Twelfth Five-Year” Science and Technology Support Program “Integrated Application of Automotive Key Lightweight Technology Development and Vehicle Integration” project promotion meeting. According to the participants, at present, China has basically broken through the lightweight design technology and evaluation methods of the vehicle body, the stamping thermoforming technology of ultra-high-strength steel parts, the advanced forming technology of high-strength steel parts, the modular design and application technology of fiber reinforced plastics, and the deformation of aluminum alloy. Key technologies for automotive lightweighting, such as parts development and a variety of lightweight technology integration applications that target vehicle weight reduction.
    New materials continue to emerge
    Wang Zhiwen, deputy secretary-general of the National Automobile Lightweight Technology Innovation Strategy Alliance, believes that cars are not the heavier and safer cars. Even if a very light material is used in a car, it is safer to achieve a very good elasticity if a high-strength process is used. In recent decades, automotive steel sheets have become thinner and thinner, and steel strength and corrosion resistance have also been greatly enhanced. The body of the car is welded together by steel plates of different strengths, and the steel plates of different strength grades are used in different positions of the force environment. For safety reasons, some of the stress conditions are harsh, and the position where thick steel plates cannot be used (such as impact beams and some reinforcement parts) mostly use high-strength steel.
    However, after the material strength is increased, it also brings some problems, mainly because the processing difficulty becomes larger. Generally, cars are manufactured by stamping, that is, molding with a die extrusion material. The strength of the steel plate for the car has put forward higher requirements for the stamping process, and now there are many deep-drawn parts, and the material is prone to cracks and wrinkles. In order to avoid this, manufacturers must study the deformation of the steel plate during stamping to prevent the steel sheet from tearing during stamping. However, the contradiction between the steel plate strength and the harder the stamping is always present.
    In order to fundamentally solve the stamping problem of high-strength steel, a new type of steel is used in the production of automobile bodies. The matrix of this steel is a relatively soft and tough ferrite, in which martensite with good hardness is embedded, which is easier to form during stamping and has considerable strength after molding. Therefore, this new type of automotive steel will make cars safer.
    At present, the thickness of the steel plate for vehicles has dropped to 0.6 mm. Analyst Luo Baihui said that this may have reached the limit of the thickness of the steel plate. Even if the steel plate is thinner, its own strength is higher, and the structural stability of many materials itself is lost. Nowadays, automotive steel sheets are increasingly challenged by new materials. The atomic weight of iron determines that its density cannot be changed, and the road of weight reduction through thinning seems to have come to an end.
    It is understood that the National Automobile Lightweight Technology Innovation Strategic Alliance is cooperating with Changan Automobile Group to jointly develop and promote the hood of “aluminum-based steel”. According to Wang Zhiwen, this study is based on the consideration of protecting pedestrian safety in the event of an accident. Because the application of aluminum alloy in the hood and other parts can reduce the secondary damage caused by the impact. Although the weight of the aluminum plate is about 1/3 of that of the steel plate, the absorbable energy of the aluminum plate is twice that of the steel plate. Aluminum alloys have a higher safety factor in the event of impact, because their materials have very good energy absorption. Nowadays, aluminum alloys are gradually being widely used in high-end cars. All-aluminum SUVs have emerged, and high-end cars that use aluminum as the front structure are also being emulated by the industry.
    For some steel companies, automotive steel accounts for about one-third of current product sales. In order to guarantee the market of automotive steel and the impact of new materials, many steel companies are actively working with automobile companies to develop a new generation of lightweight high-strength steel, which is expected to compete with aluminum alloy, plastic and carbon fiber composite materials.
    Composite materials still take time
    According to the data of the American Chemical Industry Association, the total weight of automotive plastic parts is currently less than 1/10 of the total weight of the car. Therefore, the space for expansion of applications is still very broad. The only disadvantage of composite materials is the poor flame retardancy, but can be improved by adding flame retardant materials. In recent years, in order to enhance the competitive advantage of the market, various car companies have developed and adopted lightweight models. BMW will mass-produce BMWi3 pure electric vehicles this fall. The biggest feature of this car is that the outer casing material is plastic and the chassis material is aluminum alloy. Compared with the traditional similar models, it can realize weight loss of 250 kg to 350 kg.
    Among the local car companies, Great Wall Motor Co., Ltd. and Chery Automobile Co., Ltd. are the two car companies that have the furthest in this research field. The front fender of Chery's A3CC Coupe is made of Noryl GTX resin. At the 2012 Beijing Auto Show, the seven window components of the Haval E concept car exhibited at Great Wall were made of Bayer modular polycarbonate and equipped with large panoramic sunroofs. This is the first time that China's local automakers have applied polycarbonate windows in such a wide range. In addition, in addition to the family car market, the weight of trucks has long been put on the agenda. Beiqi Foton has changed the bumpers of medium and heavy-duty trucks from steel to plastic, and has used glass-reinforced plastics in some auto parts, and also replaced some steel engine parts with plastic parts.
    However, despite the fact that foreign automakers are becoming more mature in terms of lightweighting, domestic automakers are still in the stage of learning or catching up. “This is because the domestic composites industry is still relatively backward, especially high-end materials are completely controlled by some foreign chemical companies. They master the design techniques, analytical techniques and component design techniques of materials. Because of high-end materials such as high-strength carbon fiber. Materials, long-term monopoly by foreign technology led to high product costs, some companies can only give up the use of high-end materials in the car." Zhao Honghan, deputy secretary-general of China Unsaturated Polyester Resin Industry Association said.
    In the gap between the 2nd International Automotive Lightweight Innovation Materials and Forming Technology Application Summit held recently, Jiang Dingfeng, a senior engineer of Haiyuan Machinery, once told the media that his company is investigating the complete equipment market for carbon fiber auto parts. "The time for the official launch of the equipment is still not accurate. We still need to make some investment in technology, and we must find the entry point of the market. Personally, it is estimated to come out in 2017 and 2018." He said that there are still few enterprises in the world. It is capable of mass production of carbon fiber auto parts and equipment, "BMW is also just developed." In addition, he said, only carbon fiber materials can reduce the weight of the car by 50% to 60%, and the current material can only reduce the weight of the car by about 25%.

TypeInfo: Industry news

Keywords for the information:

欢乐彩票 福彩欢乐生肖 欢乐生肖开奖视频 金牛彩票开奖 重庆欢乐生肖怎么玩 欢乐生肖彩票 欢乐彩票 重庆欢乐生肖开奖 重庆欢乐生肖开奖结果查询 重庆福彩欢乐生肖玩法