Coal-based Powdered Activated Carbon Coal-Based Activated Carbon,Coal-Based Granular Activated Carbon,Coal-Based Columnar Activated Carbon,Coal-Based Powdered Activated Carbon Ningxia YiFeng RuiDa Activated Carbon Co.,LTD , https://www.nxyfrdhxt.com
In recent years, with the rapid development of the automobile industry, the problems of fuel consumption, environmental protection and safety generated by automobiles have received increasing attention. Looking ahead to the future direction of the automotive industry, lightweight, low fuel consumption and low emissions are the development themes. According to the statistics of international authoritative departments, 60% of the fuel energy of automobile fuel is consumed by its own quality, although high-strength steel sheets, aluminum materials, magnesium materials, metal matrix composite materials and plastic resin materials have already played a role in reducing the weight of automobiles. The role, but the emergence of industrial titanium materials has made car manufacturing a better choice.
Titanium has the advantages of low density, high specific strength and good corrosion resistance. Titanium materials can greatly reduce the body quality, reduce fuel consumption, improve engine efficiency, improve the environment and reduce noise. However, the expensive price makes titanium alloys only have some applications in luxury cars and sports cars, and is rarely used in ordinary cars. Therefore, the research and development of low-cost titanium alloys adapted to the needs of the market is the key to its application to ordinary household cars.
Application Status of Titanium Alloy in Automobile Industry
Although titanium alloys have been widely used in the aerospace, petrochemical, and ship industries, their applications in the automotive industry have been slow. Since the first all-titanium car developed by GM in 1956, titanium auto parts did not reach mass production until the 1980s. In the 1990s, with the increasing demand for luxury cars, sports cars and racing cars, titanium The components have been developed rapidly. In 1990, the amount of titanium used in automobiles worldwide was only 50t. In 1997, it reached 500t. In 2002, it reached 1100t. In 2009, it reached 3,000t. It is expected that the amount of titanium used in automobiles worldwide will exceed 5000t in 2015. At present, titanium alloy parts are commonly used in the following.
Engine connecting rod
Titanium alloys are ideal for materials used in connecting rods. Engine connecting rods made of titanium alloy can effectively reduce engine quality, improve fuel efficiency and reduce exhaust. Compared to steel connecting rods, titanium connecting rods can reduce the quality by 15% to 20%. The application of the titanium alloy connecting rod was first demonstrated in the Italian Ferrari sedan 3.5LV8 and Acura's NSX engine. Titanium alloy connecting rods are mainly Ti-6Al-4V, Ti-10V-2Fe-3Al, Ti-3Al-2.0V and Ti-4Al-4Mo-Sn-0.5Si, etc. Other titanium alloy materials such as Ti-4Al The use of -2Si-4Mn and Ti-7M-4Mo in the connecting rod is also under development.
2. Engine valve
Automotive engine valves made of titanium alloy can not only reduce the quality, extend the service life, but also reduce fuel consumption and improve the reliability of the car. Compared with steel valves, titanium valves can reduce the quality by 30% to 40%, and the engine limit speed can be increased by 20%. For the current application, the material of the intake valve is mainly Ti-6Al-4V, and the material of the exhaust valve is mainly Ti-6242S. Usually, Sn and Al are added together, which can obtain lower brittleness and higher. The strength; the addition of Mo can improve the heat treatment performance of the titanium alloy, strengthen the strength of the quenching and aging titanium alloy, and increase the hardness. Other titanium alloys with development potential are:
1) The intake valve can be Ti-62S, its characteristics are equivalent to Ti-6Al-4V, and the price is cheaper.
2) The exhaust valve can be Ti-6Al-2Sn-4.0Zr-0.4-Mo-0.45Si. Because of its low Mo content, its resistance to creep resistance is better than Ti-6242S, and the oxidation resistance temperature can reach 600°C. .
3) The exhaust valve can adopt γ-TiAl, which has the characteristics of high temperature resistance and light weight, but it is not suitable for the traditional forging method during processing, and is only suitable for casting and powder metallurgy processing.
3. Valve spring seat
High strength and fatigue resistance are the properties that must be possessed by the valve spring seat. The β titanium alloy is a heat treatment type alloy, which can obtain high strength by solution aging treatment. The corresponding suitable material is Ti-15V-3Cr- 3Al-3Sn and Ti-15Mo-3Al-2.7Nb-0.2Si. Mitsubishi Motors uses Ti-22V-4Al titanium alloy valve spring seat on its large-scale production car, which reduces the quality by 42% compared with the original steel lock. The valve mechanism reduces the inertial mass by 6%, and the maximum engine speed increases. 300r/min.
4. Titanium alloy spring
Titanium and its alloys have a lower modulus of elasticity than steel materials and have a large σs/E value, making them suitable for the manufacture of elastic components. Compared with steel automobile springs, under the premise of the same elastic work, the height of the titanium spring is only 40% of the steel spring, and the quality is only 30% to 40% of the steel spring, which is convenient for the car body design. In addition, the excellent fatigue properties and corrosion resistance of titanium alloys increase the service life of the spring. At present, titanium alloy materials which can be used to manufacture springs for automobiles include Ti-4.5Fe6.8Mo-1.5Al and Ti-13V11C-3Al.
5. Turbocharger
Turbochargers increase engine combustion efficiency and increase engine power and torque. Turbocharger turbine rotors require long-term operation in high-temperature exhaust gas above 850 °C, so good heat resistance is required. Conventional light metals such as aluminum alloys cannot be used because of their low melting point. Although ceramic materials are used on turbine rotors because of their light weight and high temperature resistance, their application is limited due to their high cost and inability to optimize their shape. In order to solve these problems, Tetsui et al. developed a TiAl turbine rotor. After many tests, it not only has good durability and performance, but also improves the acceleration of the engine. This design has been successfully commercialized on the Mitsubishi Lancer Evolution series.
6. Exhaust system and muffler
Titanium is used in large quantities in automotive exhaust systems. Exhaust systems made of titanium and its alloys not only improve reliability, extend life and improve appearance, but also reduce quality and improve fuel combustion efficiency. The titanium exhaust system can be reduced in mass by approximately 40% compared to steel exhaust systems. In the Golf series, the quality of the titanium exhaust system can be reduced by 7 to 9 kg. Currently, the titanium used in the exhaust system is mainly industrial pure titanium.
The quality of the titanium muffler is only 5 to 6 kg, which is lighter than the muffler such as stainless steel. The 2000 Chevrolet Corvette Z06 replaced the original 20kg stainless steel system with a 11.8kg titanium muffler and exhaust pipe system, reducing the mass by 41%. The replacement system has the same strength and makes the car faster, more flexible and fuel efficient. The titanium used in the muffler is also mainly industrial pure titanium.
7. Body frame part
In order to improve the safety and reliability of automobiles, it is necessary to consider design and manufacturing aspects, especially materials. Titanium is a very good material for making car body frames, which not only has higher strength but also good toughness. In Japan, car manufacturers choose pure titanium welded pipes to make body frames, which can give drivers a sense of security when driving.
8. Other titanium alloy parts
In addition to the above components, titanium is also used in engine rocker arms, suspension springs, engine piston pins, automotive fasteners, lug nuts, automotive door sills, car block brackets, brake caliper pistons, pin bolts, pressure Auto parts such as plates, shift buttons and automotive clutch discs.
Application of titanium alloy
Advantage
Titanium alloy has the advantages of light weight, high specific strength and good corrosion resistance, so it is widely used in the automotive industry. The most applied titanium alloy is the automobile engine system. There are many advantages to using titanium alloys to make engine parts, mainly in:
1) The low density of titanium alloy can reduce the inertial mass of moving parts. At the same time, titanium valve spring can increase free vibration, weaken the vibration of the body and improve the engine speed and output power.
2) Reduce the inertial mass of the moving parts, thereby reducing the friction and improving the fuel efficiency of the engine.
3) The choice of titanium alloy can reduce the load stress of related parts and reduce the size of parts, thus reducing the quality of the engine and the whole vehicle.
4) The reduction of the inertial mass of the components reduces the vibration and noise and improves the performance of the engine.
The use of titanium alloys on other components can improve the comfort of the person and the aesthetics of the car. In the automotive industry, titanium alloys play an invaluable role in energy saving.
2. Application restrictions
Titanium alloy parts, despite their superior performance, are still far from the general application of titanium and its alloys in the automotive industry due to problems such as high cost, poor formability and poor weldability.
With the recent development of titanium alloy near net forming technology and modern welding techniques such as electron beam welding, plasma arc welding and laser welding, the forming and welding of titanium alloys is no longer a key factor restricting the application of titanium alloys, hindering titanium alloys. The most common cause of widespread use in the automotive industry is cost.
Whether it is the initial metal smelting or subsequent processing, the price of titanium alloy is much higher than other metals. The cost of titanium parts acceptable to the automotive industry is 8 to 13 US dollars per kg of connecting rod titanium, 13 to 20 US dollars per kg of titanium for gas valves, and titanium for springs, engine exhaust systems and fasteners. USD/kg or less. At present, the cost of parts produced from titanium materials is much higher than these prices. The production cost of titanium sheets is mostly higher than 33 US dollars/kg, which is 6 to 15 times that of aluminum sheets and 45 to 83 times that of steel sheets.
Research Status of Titanium Alloys for Automobiles
At present, cost reduction is the main research direction of titanium alloys for the automotive industry. In view of the characteristics of the cost distribution of titanium alloys used in the automotive industry, material research and development workers mainly achieve the purpose of reducing costs from the following two aspects: development of new low-cost alloy systems and the use of new processing and preparation technologies.
1. New low-cost titanium alloy system
National workers develop new low-cost titanium alloy systems, focusing on the following aspects: alloy design using inexpensive alloying elements and alloy design to improve processing characteristics. Among them, Japan and the United States have successfully developed two low-cost titanium alloys, namely Ti8LC and Ti12LC. In the design of low-cost titanium alloy compositions for vehicles, inexpensive alloying elements commonly used are Fe, Cr, Si, Al, and the like.
2. New processing and preparation technology
The processing cost of titanium alloy materials in the production process accounts for more than 60% of the total cost. Therefore, in terms of cost reduction, how to reduce the processing cost of titanium alloy has become the focus of research. The research in this area is mainly divided into two aspects: one is to improve the traditional casting and forging process, and the other is to use powder metallurgy near net forming technology.
In the development of the new forging process, the cold forging method is one of the most promising methods for the manufacture of auto parts for titanium alloys. The β-titanium alloy has a small deformation resistance at normal temperature and is well formed by cutting, and is a material that can be cold forged. At present, three cold-deformed β-titanium alloys have been developed in Japan. Beta titanium alloy also has some shortcomings, which are prone to uneven deformation during cold forging and tend to adhere to the mold. Therefore, further exploration and development are required for mass production of β titanium alloy parts by cold forging technology.
Powder metallurgy is an important technology in reducing the cost of processing titanium alloys. In the manufacture of powder metallurgy automotive parts, the traditional press-sintering method is still in a dominant position, mainly including the elemental powder method (BE) and the prealloyed powder method (PA). At present, the elemental powder method is the most widely used in the low-cost automobile titanium alloy powder metallurgy because of its simple process and lower cost. In recent years, other powder metallurgy technologies have emerged, including laser forming technology, metal powder injection molding (MIM) and other technologies, which have been widely used in the trial production and production of complex parts for vehicles, which can greatly shorten product development. With the production cycle, further reduce costs.
Conclusion
The new generation of car design pays more attention to the weight reduction of the body, low fuel consumption, low noise and light vibration of the engine to meet the increasingly demanding requirements of the environment. In this context, light metal titanium will become a major application choice for future cars.
Considering the current research status of low-cost titanium alloys for vehicles, it can be found that in order to further reduce the cost of titanium alloys for vehicles, the following aspects should be mainly focused on:
1) In the development of low-cost alloy systems, try to develop an alloy system that does not use or use expensive alloying elements without affecting performance, and at the same time fully develop the recycled titanium alloy.
2) In the development of casting and forging technology, the development of β-titanium alloy and cold-deformed titanium alloy is carried out, and the feasibility study of mass production is carried out.
3) In the aspect of powder metallurgy, while ensuring the low cost advantage, it is necessary to further improve the performance of titanium parts.
As the economy develops and the cost of titanium decreases, more engineers will choose titanium for automotive parts. Titanium alloys will eventually play an important role in the automotive industry.