Titanium alloys are used in the manufacture of automotive parts

In recent years, with the rapid development of the automotive industry, the issues of fuel consumption, environmental protection and safety generated by automobiles have attracted increasing attention. Looking forward to the future development direction of the automotive industry, light weight, low fuel consumption and low emissions are the development themes. According to statistics from international authoritative departments, 60% of automobile fuel combustion energy is consumed by its own mass, although currently high-strength sheet steel, aluminum, magnesium, metal-based composites and plastic resin materials have played a role in reducing the weight of automobiles Role, but the advent of industrial titanium materials has made automotive manufacturing a better choice.

Titanium has the advantages of low density, high specific strength, and good corrosion resistance. The use of titanium in automobiles can greatly reduce the body mass, reduce fuel consumption, improve engine efficiency, improve the environment and reduce noise. However, the high price makes titanium alloys only have some applications in luxury models and sports cars in the automotive industry, and rarely in ordinary cars. Therefore, research and development of low-cost titanium alloys that meet the needs of the market are the key to promoting its application to ordinary household cars.

Application Status of Titanium Alloy in Automotive Industry

Although titanium alloys have been widely used in the aerospace, petrochemical, and shipbuilding industries, their application in the automotive industry has been slow. Starting from the successful development of the first all-titanium automobile by General Motors of the United States in 1956, titanium automobile parts did not reach the level of mass production until the 1980s. In the 1990s, with the increase in demand for luxury cars, sports cars and racing cars, titanium Manufacturing parts have developed rapidly. In 1990, the amount of titanium used in automobiles worldwide was only 50t, reached 500t in 1997, 1100t in 2002, and 3000t in 2009. 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 as follows.

1. Engine connecting rod

Titanium alloy is ideal for connecting rod materials. The engine connecting rod made of titanium alloy can effectively reduce the quality of the engine, improve the fuel efficiency and reduce the exhaust volume. Compared with steel connecting rods, titanium connecting rods can reduce the weight by 15% to 20%. The application of the titanium alloy connecting rod was first reflected in the new Ferrari 3.5LV8 in Italy and the NSX engine of Acura. The materials used for titanium alloy connecting rods are mainly Ti-6Al-4V, Ti-10V-2Fe-3Al, Ti-3Al-2.0V, and Ti-4Al-4Mo-Sn-0.5Si. Other titanium alloy materials such as Ti-4Al The application of -2Si-4Mn and Ti-7M-4Mo in connecting rods is also under development.

2. Engine valve

The automobile engine valve made of titanium alloy can not only reduce the quality and extend the service life, but also reduce the fuel consumption and improve the reliability of the car. Compared with the steel valve, the titanium valve can reduce the mass by 30% to 40%, and the limit speed of the engine can be increased by 20%. In terms of current applications, the material of the intake valve is mainly Ti-6Al-4V, and the material of the exhaust valve is mainly Ti-6242S. Generally, Sn and Al are added together to obtain lower brittleness and higher The strength of Mo can improve the heat treatment performance of titanium alloy, strengthen the strength of quenched and aged titanium alloy, and increase the hardness. Other titanium alloys with development potential are:

1) The intake valve can use 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 lower Mo content, its creep resistance is better than Ti-6242S, and its oxidation resistance can reach 600 ° C. .

3) The exhaust valve can use γ-TiAl, which has the characteristics of high temperature resistance and light weight, but it is not suitable to use the traditional forging method during processing, and it is only suitable for processing by casting method and powder metallurgy method.

3. Valve spring seat

High strength and fatigue resistance are required properties of a valve spring seat. Β titanium alloy is a heat-treated alloy, which can obtain high strength through solution aging treatment. The corresponding suitable materials are Ti-15V-3Cr- 3Al-3Sn and Ti-15Mo-3Al-2.7Nb-0.2Si. Mitsubishi Motors uses Ti-22V-4Al titanium alloy valve spring seats in its large-scale production cars, which reduces the mass by 42% compared with the original steel lock, the valve mechanism reduces the inertia mass by 6%, and the maximum engine speed increases. 300r / min.

4. Titanium alloy spring

Titanium and its alloys have lower elastic modulus and larger σs / E values ​​than steel materials, making them suitable for manufacturing elastic components. Compared with steel automobile springs, on the premise of the same elastic work, the height of titanium springs is only 40% of steel springs, and the mass is only 30% to 40% of steel springs, which is convenient for car body design. In addition, the excellent fatigue and corrosion resistance of titanium alloys can increase the service life of springs. At present, titanium alloy materials that can be used to make springs for automobiles include Ti-4.5Fe6.8Mo-1.5Al and Ti-13V11C-3Al.

5. Turbocharger

Turbocharger can improve the combustion efficiency of the engine and enhance the power and torque of the engine. The turbine rotor of a turbocharger needs to work in a high-temperature exhaust gas at a temperature above 850 ° C for a long time, so it requires good heat resistance. Traditional light metals such as aluminum alloys cannot be used because of their lower melting points. Although ceramic materials are used in turbine rotors because of their light weight and high temperature resistance, their applications are limited due to their high cost and shape optimization. In order to solve these problems, Tetsui et al. Developed a TiAl turbine rotor, which has been tested and verified for many times. It not only has good durability and efficiency, but also improves engine acceleration. This design has been successfully used commercially in the Mitsubishi Lancer Evolution series.

6. Exhaust system and muffler

Titanium is widely used in the exhaust system of automobiles. Exhaust systems made of titanium and its alloys can not only improve reliability, extend life and improve appearance, but also reduce mass and improve fuel combustion efficiency. Compared with steel exhaust system, titanium exhaust system can reduce mass by about 40%. In Golf series cars, the mass of titanium exhaust system can be reduced by 7-9kg. At present, the titanium used in the exhaust system is mainly industrial pure titanium.

Titanium muffler weighs only 5-6kg, which is lighter than stainless steel and other mufflers. The 2000 Chevrolet CorvetteZ06 replaced a 20kg stainless steel system with a 11.8kg titanium muffler and exhaust pipe system, reducing mass by 41%. The strength of the replaced system remains the same, making the car faster, more flexible and fuel efficient. The titanium material used in the muffler is also mainly industrial pure titanium.

7. Car body frame part

In order to improve the safety and reliability of automobiles, it is necessary to consider from the aspects of design and manufacturing, especially the manufacturing materials. Titanium is a very good material for making car body frames. It has not only higher specific strength but also better 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 parts, titanium is also used in engine rocker arms, suspension springs, engine piston pins, automotive fasteners, mounting ear nuts, car door intrusive beams, car brackets, brake caliper pistons, pin bolts, pressure Auto parts such as plates, shift buttons and car clutch discs.

Titanium alloy applications

1. Advantages

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 widely used titanium alloy is automotive engine systems. There are many benefits 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 the free vibration, reduce the vibration of the vehicle body, and increase the engine speed and output power.

2) Reduce the inertial mass of moving parts, thereby reducing 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, thereby reducing the quality of the engine and the entire vehicle.

4) The reduction of the inertial mass of parts makes the vibration and noise weaken and improves the performance of the engine.

The application of titanium alloy on other components can improve the comfort of the personnel and the aesthetics of the car. In the automotive industry, titanium alloys have played an inestimable role in saving energy and reducing consumption.

Email: jasontitanium@163.com

Whatsapp / Skype / Wechat / Line: + 86-15829508781