SMM7: at the 2020 China Ni-Cr stainless Steel Industry Market and Application Development Forum held in SMM on July 20, Liang Juxing, an expert on stainless steel car body of CRRC Nanjing Puzhen vehicle Co., Ltd., explained the application status of stainless steel car body of urban rail vehicles, and looked forward to the future development.
Introduction of rail vehicles
In 1863, the world's first underground railway line drawn by a steam locomotive was completed and opened to traffic in London, England. From 1863 to 1899, seven cities in five countries, including London and Glasgow in the United Kingdom, New York and Boston in the United States, Budapest in Hungary, Vienna in Austria and Paris in France, took the lead in building the subway. The first electric locomotive was successfully studied in 1879; the first city in China with a subway: Beijing Metro was completed and opened to traffic in October 1969 with a line length of 23.6km; the second ring line was completed and opened to traffic in September 1984, with a full length of 19.9km. By 2013, the total mileage is 456km; the first city in China to have a modern subway: Shanghai Metro Line 1 was completed and opened to traffic in May 1995, with the total length of 21km and the introduction of German Siemens technology; after 2008, domestic urban rail transit has comprehensively moved towards the era of independent innovation, established a complete variety of rail transit system, and gradually formed a relatively perfect standard system.
Introduction of stainless steel vehicles at home and abroad
Domestic situation-Model A car
Since 2000, the model A project has a total of 116projects and 19528 vehicles.
From the perspective of car body materials, there are 109 items of aluminum alloy car body, accounting for 94%, and the number of vehicles is 17814, accounting for 91.2%. From the point of view of the highest running speed, there are 87 projects with the highest running speed of 80km/h, accounting for 77.7%, and the number of vehicles is 14688, accounting for 78.2%.
Aluminum alloy vehicles account for the vast majority, stainless steel car body vehicles are mostly concentrated in Beijing. There are 20 projects with the highest running speed of 80-100km/h, accounting for 17.8%, and the number of vehicles is 3300, accounting for 17.6%.
In recent years, the proportion of vehicles with maximum speeds of 100km/h or above has gradually increased by about 10 per cent.
Domestic situation-Model B car
Since 2000, there have been a total of 209 model B projects with 28272 vehicles.
From the perspective of car body materials, there are 112 items of aluminum alloy car body, accounting for 53.6%, and the number of vehicles is 15316, accounting for 54%.
Stainless steel car body has 93 projects, accounting for 44.5%, the number of vehicles is 12696, accounting for 44.9%; aluminum alloy material is slightly more.
Introduction of stainless Steel car body of Rail vehicle
Subway vehicle is one of the most important mechanical and electrical equipment in the whole subway system.
The vehicle itself is a complex system formed by multi-stage coupling of multiple systems; at the same time, the external interfaces are also numerous and complex.
Vehicle main system:
Car body system built-in system door system
Air conditioning system braking system traction system
Auxiliary system Train Network system passenger Information system
Lighting system, train control system, electromechanical system.
The interface between vehicles and other professions
Major in signal and communication (radio, terrestrial PIS, TE)
Power supply specialty catenary specialty ground ventilation and air conditioning major
The screen door professional track specialty does not fall off the wheel.
Power supply for car washing machine frame workshop
Comparison of car body materials
Safety: the melting point of stainless steel is 1500 ℃, the melting point of carbon steel is 1300 mi 1500 ℃, and the melting point of aluminum alloy is 660 ℃. The heat resistance of aluminum alloy is only 44% of that of stainless steel.
Lightweight (type B car): carbon steel car body is about 8.8t, stainless steel car body is about 8.1t, aluminum alloy car body is about 6.2t.
Based on the carbon steel car body, the weight of the stainless steel car body is reduced by 8%, and the weight of the aluminum alloy car body is reduced by 30%. Aluminum alloy car body makes a great contribution to reducing energy consumption.
Corrosion resistance: stainless steel and aluminum alloy car body have better corrosion, but stainless steel car body is superior. Stainless steel car body does not need anti-corrosion protection, can be decorated with color plastic film. Aluminum alloy is easy to be corroded by cl ion, so it needs to be painted.
Advantages and disadvantages of car body materials
Appearance quality: the external surface of aluminum alloy car is smooth, straight and straight, and you can choose different decorative colors, which makes people feel beautiful, generous and easy to accept. Unpainted stainless steel car body is very sensitive to flatness, as long as there are 0.2mm bumps and bumps, reflected by light, the naked eye will feel uncomfortable, especially the spot welding marks of the thin plate can not be eliminated, and the consistency of the arrangement, depth and size of the solder joints are strictly required.
Ability to resist bumps and scratches: aluminum alloy is dominant and can be repaired. Because stainless steel is a thin plate and a drawing plate, it is easy to scratch, and it is more taboo to scratch in the opposite direction.
The installation space and layout of the equipment under the car: aluminum alloy car body, large space under the car, adapt to the pre-assembly of large wire grooves and air pipes, achieve overall hoisting, and achieve modular requirements; stainless steel car body, plate beam spot welding structure, small space under the car, equipment layout is scattered, wire slot, pipeline is difficult to achieve modularization.
Process: stainless steel needs to be spot welded, the air tightness of the car body is poor, and the use of high-speed vehicles is limited, so it can be used in subway and light rail. The large hollow aluminum alloy profile car body is an integral welding structure, which adopts automatic welding and modular structure.
The influence of car body materials on vehicles: the car bodies of different materials and structures are basically the same in terms of service life, reliability, safety and so on. The main differences are as follows:
In the face of increasingly stringent energy conservation and emission reduction requirements, high-speed, energy-saving, safety, comfort and environmental protection have become the development direction in the field of transportation. As the key technology of green energy saving, lightweight will be the inevitable trend of the development of transportation equipment.
For rail transit, vehicles have important practical significance:
The reduction of vehicle weight can reduce the running resistance and save the energy needed for traction and braking.
Reduce the impact on the track, so as to reduce the wear of wheels and rails;
Reduce the maintenance cost of vehicles and tracks;
Directly reduce the materials used to build vehicles.
In people's impression, lightweight means to reduce the weight of the car body. Lightweight should be for the vehicle as a whole, all components, facilities, equipment and materials on the vehicle should be lightweight, just like the lightweight of the car body, and the cost and risk may be smaller. Vehicle lightweight should be comprehensively considered from the aspects of material lightweight, structure lightweight, new technology lightweight and so on.
The weight of the car body structure accounts for about 2030% of the whole vehicle, so the lightweight of the car body structure has a great contribution to the lightweight of the whole vehicle.
Application of composite materials
Taking the Japanese Shinkansen vehicle as the object, the large cross-section CFRP car body structure was trial-manufactured and the strength test was carried out. The length of the trial-produced car body is 6m. However, this technology requires several segments of the car body to be bolted or bonded together, and the stiffness of the connection position is poor, which can not meet the conditions of commercial operation.
French TGV train body structure is also a mixed material car body, similar to the Japanese technology, also due to poor stiffness can not meet the conditions of commercial operation.
The Swiss company Schindler Waggon adopts filament-wound rectangular control of railway passenger cars. Compared with the aluminum car body, the weight of the car body can be reduced by 20% to 25%.
The German company Adtranz has developed a kind of bus body with mixed structure of FRP and metal called Regio Shuttle. The car body adopts steel body frame. The phenolic FRP sandwich board is used as the car body plate, and the car body plate is fixed on the steel frame with special elastic adhesive.
Sweden's C20 FICA operated in Stockholm on July 16, 2003. Its side wall, floor and roof all adopt MPI foam sandwich stainless steel sandwich structure. The most representative and successful case is South Korea's TTX tilting train, which was put into commercial operation in 2010, with 6 sections, 4 movements and 2 tows, with a design speed of 200km per hour and an operating speed of 180km. The roof, side wall and end wall are formed with mixed materials, and the underframe is made of stainless steel. Compared with the stainless steel structure of the whole vehicle, the weight is reduced by about 39%.
The Application Direction of stainless Steel vehicles
At present, the domestic stainless steel roll bending part is a single plate thickness roll bending technology. If the roll bending technology with complex cross-section and variable cross-section can be developed, it will be of great help to the lightweight of car body structure.
Strengthen the fusion of stainless steel and composite materials. Develop a new structure of structural lightweight composite materials.
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