Current application status of titanium alloys in rail transit vehicles
Railroad vehicles (Railway Cars, RVs) are a means of transportation that run on railway lines. They refer to trains that use railways or urban rail transit lines as their operating platforms. They are composed of power systems, braking systems, traction systems and other auxiliary systems. It is an engineering technology product with specific functions that meets the needs of transportation production and has an impact on the environment.
Rail transit vehicles use electricity as energy source and mainly include locomotives, passenger cars, trucks and rail cars. At present, our country has the largest railway network in the world and is the only country in the world with four major modern transportation modes: subway, light rail, high-speed railway and passenger dedicated line.
In rail transit vehicles, the most important structural materials currently are aluminum alloy and steel. Among them, aluminum alloy is widely used in train structural materials due to its advantages such as light weight, high strength and good corrosion resistance; steel is widely used in car body structural materials due to its advantages such as high strength and good corrosion resistance.
With the acceleration of urbanization in our country, urban rail transit has developed rapidly, which has also put forward higher requirements for vehicle structural materials.
Therefore, materials such as aluminum alloys and steel used in urban rail transit vehicles need to be lightweight designed to a certain extent. In recent years, titanium alloys have been widely used in rail transit vehicles due to their low density, high specific strength, corrosion resistance, high temperature and low temperature resistance and other properties.
Research status of titanium alloys in rail transit vehicles
The application of titanium alloys first began in the 1940s. Due to its advantages such as high strength, light weight, and corrosion resistance, the application of titanium alloys in rail transit vehicles is mainly concentrated in traction and braking systems.
In the 1960s, French scientists used titanium alloys in rail transit vehicle traction systems, mainly in low-friction coefficient CRH2 EMUs, low-friction TGV EMUs and low-friction TGV subway vehicles.
The CRH2 train traction system developed by French engineers is made of titanium alloy. This is the first time in the world that titanium alloy has been used.
In the 1970s, the German and Italian railway departments used titanium alloys in rail transit vehicle braking systems, mainly in train braking devices, including main brakes, brake discs and brake pads.
During the train braking process, titanium alloy can absorb a large amount of heat energy, thereby effectively reducing the friction coefficient between the wheels and rails; at the same time, titanium alloy will not produce sparks during the braking process, avoiding fire hazards caused by friction.
After the 1980s, countries around the world gradually realized the advantages and value of titanium alloys in rail transit vehicles, and began to apply them to rail transit vehicles.
France, Germany, Italy, Japan and other countries are actively studying the application technology and development prospects of titanium alloys in rail transit vehicles. France began research on the application of titanium alloys in rail transit vehicles in the late 1980s.
Japan began to conduct research on the application technology of titanium alloys in rail transit vehicles in the mid-1980s. The University of Tokyo, Hokkaido University, Waseda University, etc., and railway vehicle manufacturing companies jointly carried out research on the application technology of titanium alloys in rail transit vehicles.
Since the mid-1990s, countries around the world have made greater progress in research on the application technology of titanium alloys in rail transit vehicles. The United States, the United Kingdom, Australia, Canada and other countries use titanium alloys to manufacture brake discs and brake pads for high-speed trains.
The University of Tokyo in Japan has carried out extensive research work on high-speed train brake disc materials and manufacturing processes. Germany began titanium alloying of brake discs for high-speed trains in the early 1990s.
However, the application of titanium alloys in domestic rail transit vehicles is still in its infancy. If we want to promote the use of titanium alloys in rail transit vehicles on a large scale, the following problems need to be solved:
To improve the application efficiency and quality of titanium alloys in rail transit vehicles, it is mainly to solve the problems such as cracks, pores and slag inclusions that are prone to occur in titanium alloys during the welding process, and to formulate unified, standardized and scientific titanium alloy welding process specifications and Testing methods to guide and improve the quality of titanium alloy welding.
According to the structural characteristics of rail transit vehicles and the requirements of the service environment, a corresponding standard system is established to guide the application of titanium alloys in rail transit vehicles in my country. Of course, my country still faces many challenges in the application of titanium alloys in rail transit vehicles.
references
Li Feng "Research and Application of High-Strength and Heat-Resistant Aluminum Alloys for High-speed Railway High-speed EMUs" Journal of Beijing Jiaotong University, 2009.
Su Yongjun "Research Progress on the Application of New Titanium Alloys in Rail Transit Vehicles" National Rail Transit Equipment Quality Supervision and Inspection Center Co., Ltd., 2017.
Liu Lifeng "Lightweight design method and application of subway trains based on computer simulation technology" Journal of Engineering Materials, 2012.
Liu Shihui "Research Progress in Design and Manufacturing Technology of High-Strength and Heat-Resistant Titanium Alloys for High-speed Trains" Railway Science and Technology, 2014.
Xie Keqiang "Discussion on Research Progress and Application Development Direction of High-Performance Titanium Alloy Materials and Manufacturing Technology" Journal of Chinese Nonferrous Metals, 2016.
