Titanium and titanium alloys have the characteristics of low density, excellent mechanical properties, good biocompatibility, corrosion resistance, high temperature resistance, and good low-temperature toughness, and have been widely used in the automotive manufacturing field. Titanium alloy has a density of only 60% that of steel, and its strength can reach over 800MPa. It still maintains good mechanical properties at around 500 ℃, and has good welding and forming properties. It has been used in the manufacturing of racing cars for over 20 years, greatly reducing the quality of racing engines and improving engine performance.

At present, titanium alloy components used in automobile manufacturing are mainly distributed in the exhaust system, engine system, transmission and damping system, and body frame parts of automobiles.

1. Exhaust system

Automotive exhaust system materials are required to have good high-temperature mechanical properties and corrosion resistance to S and Cl elements. Traditional exhaust valve components are made of stainless steel, but it has been found that titanium alloy is more suitable as an exhaust valve material in terms of performance.

The titanium return pipe used on the new Chevrolet Corvette Z206 effectively avoids problems such as pitting and weld corrosion on stainless steel pipes, while also improving fuel combustion efficiency and acceleration ability, and shortening braking distance.

The largest titanium manufacturer in the United States, Timet, has been committed to the research and manufacturing of titanium alloy exhaust systems, and several Japanese companies have also carried out related research and development work. Currently, Fuji Heavy Industries has limited the production of 440 sets of titanium alloy automotive exhaust pipes.

2. Engine system

The automotive engine system is the component that uses titanium alloy the most in the automotive industry. The main applications of titanium alloy in engine systems include valves, connecting rods, crankshafts, valve seats, and other components.

Honda Motor Company of Japan used forged titanium connecting rods in the NSX racing V-6 engine; The high capacity, four cylinder engines manufactured by Mitsubishi Motors use titanium valve spring seats, and Porsche cars also use titanium connecting rods.

(1) Valve

In terms of titanium alloy valves, both the United States and Japan have conducted extensive research work. Currently, the United States generally uses Ti-6Al-4V alloy to manufacture inlet valves and Ti-6Al-2Sn-4Zr-2M o alloy to manufacture exhaust valves; Toyota, on the other hand, uses Ti-6Al-4V/Ti B alloy to prepare the intake valve and Ti-Al-Zr-Sn-Mo-Nb-Si/Ti B alloy to prepare the exhaust valve. These types of titanium alloys all have good high-temperature mechanical properties, oxidation resistance, and creep resistance, effectively improving engine performance and increasing car speed.

(2) Valve seat

Titanium alloy valve seats have been widely used in racing and sports cars, producing over 250000 sets annually. They are mainly made of Ti-6Al-4V or Ti-5Al-2Cr-1Fe alloy. Due to the simple shape of the valve seat, there are not high requirements for mechanical processing, and no special surface treatment is required. The cost is relatively low, and the effect on weight reduction in automobiles is significant.

(3) Connecting rod

The use of titanium alloy connecting rods can effectively reduce the mass of the engine and improve car performance. At present, the main preparation material is Ti-6Al-4V alloy. Japan's Datong Corporation is currently developing a two-phase titanium alloy Ti-3Al-2V-0.2Si-0.47Ce-0.27La, which has good cutting properties and excellent mechanical, fatigue, and corrosion resistance. It is expected to be used in connecting rod components for rapid acceleration and deceleration of engines.

(4) Crankshaft

Although titanium alloy crankshafts have not been widely used, the Ti-3Al-2.5V alloy specifically developed in Japan has been validated on Honda racing cars, effectively reducing mass while increasing engine speed by 700r/min, proving the superiority of titanium alloy crankshafts. Meanwhile, Japan has been trial-producing Ti-5Al-2Cr-Fe alloy crankshafts, hoping that titanium alloys will be more widely used in crankshaft components.

3. Damping system

The core component of the automotive suspension system is the suspension spring. Compared to steel for general automotive springs, titanium alloy has higher specific strength and lower shear modulus, as well as higher fatigue strength, making it more suitable for manufacturing automotive shock absorbers. Due to the fact that the deflection of the spring is proportional to the number of turns and inversely proportional to the shear modulus of the material, titanium alloy springs require fewer turns than steel springs to achieve the same spring response, effectively reducing spring mass and saving space.

At the same time, titanium alloy springs can effectively increase the resonance frequency of the spring and improve its service life. Currently, most titanium alloy springs are single-phase β Preparation of titanium alloys. Volkswagen has already used Lupo FSI titanium alloy gear springs on some cars, with a usage of approximately 3500 vehicles.

4. Vehicle body frame

In terms of body frame components, titanium alloy has a high specific strength, low density, and good corrosion resistance, all of which indicate that it is a good material for preparing body frames. At present, some car companies have used titanium alloy on components such as gear brackets, brake calipers, and pistons. In terms of transmission components, Japan is currently developing a high spin forming process to prepare titanium alloy shells. Compared with steel shells, titanium alloy shells better reduce the impact of the flywheel and have better cushioning effects.

In addition, titanium alloys have also been applied in automotive fasteners and other components. With the continuous development of titanium alloy preparation processes and the automotive industry, titanium and titanium alloys will play an increasingly important role in China's modern automotive industry, promoting the continuous development of the automotive industry.