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Suqian City, Jiangsu Province
Building C1, Laser Industrial Park
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Building C1, Laser Industrial Park
+86 19852658006
sales@jshylaser.com
In recent years, with the transformation of China railway lines and the improvement of transport capacity demand, domestic railway rolling stock has entered a period of rapid renewal. During the whole “13th Five-Year Plan” period, the demand of domestic railway rolling stock market will continue to rise. At the same time, infrastructure interconnection is a priority area for the construction of “the belt and road initiative”, and the release of “the belt and road initiative” has further promoted the development of rail transit industry. In order to meet the needs of the leap-forward development of locomotive and rolling stock industry, domestic railway passenger car and urban rail vehicle manufacturing industries are also actively carrying out comprehensive technical equipment transformation and product technical upgrading, and laser cutting and laser welding are one of the key technologies in their manufacturing.
During the “Twelfth Five-Year Plan” period, due to the problems of poor sealing and large welding deformation of stainless steel car bodies, the country chose aluminum alloy car bodies with higher production costs and relatively lower safety performance when vigorously developing high-speed rail buses. With the further increase of my country’s demand for rail vehicles during the “13th Five-Year Plan” period, the advantages of stainless steel car bodies in terms of manufacturing costs will be valued. Different from the traditional welding technology, due to the excellent transmission and focusing characteristics of the laser, all the energy can be concentrated in a small area. Therefore, the energy is highly concentrated during laser welding, with high speed, high precision, high quality, low deformation, It is considered to be one of the welding methods with the most development potential in the 21st century.
Laser processing technology is the most important manufacturing technology method in the locomotive manufacturing industry in recent years, which has greatly promoted the improvement of the locomotive manufacturing process level. Mayman Technology has innovated and upgraded the laser cutting technology accumulated over the years, launched efficient and professional locomotive manufacturing industry solutions, and pushed railway locomotive manufacturing technology into a new era.
Comparison between traditional welding methods and laser welding
Resistance spot welding | Leaving indentations on the surface of the outer panel, affecting the aesthetics. Poor sealing, unsuitable for high-speed vehicles. A large number of welding joints gathered in one part, deformation is large. |
Electric arc welding | High heat input, high deformation and low precision. Low weld strength (Al alloy) and poor forming. Slow welding speed and low production efficiency. |
Laser Welding | No weld marks on the outer surface of the skin and beautiful car body. Low heat input, low welding deformation, high welding accuracy, improving the dimensional accuracy of the whole vehicle. Easy automation, while improving the stability of the weld quality. High welding efficiency. Continuous welding, high strength and sealing of the car body. |
Laser Welding of Stainless Steel
The use of stainless steel car bodies is becoming more and more widespread:
● The United States and France began to use stainless steel to manufacture train bodies as early as the 1930s.
● The Hyogo Plant of Japan Kawasaki Heavy Industries Co., Ltd. formally introduced laser welding in the welding of stainless steel railway vehicles, which increased the operation by 20%-30% and reduced the cost by 20%-30%.
● In July 2003, Changchun Railway Vehicle Co., Ltd. developed the first stainless steel urban rail vehicle. This vehicle adopts the overall spot welding structure of the drum-shaped car body, which marks the realization of my country’s urban rail vehicle technology from carbon steel body to stainless steel. The successful crossing of the bodywork.
● Domestic Changchun Vehicle Works, Sifang and Zhuzhou Electric Locomotives have carried out preliminary research on laser welding technology for stainless steel car bodies, and have begun practical applications.
The welding performance of stainless steel is mainly restricted by the following two physical properties :
● Large coefficient of thermal expansion
The coefficient of thermal expansion is about 1.5 times that of carbon steel, which makes the deformation much larger than that of ordinary steel with the same heat during welding.
● Low thermal conductivity
The thermal conductivity is about 1/3 of that of ordinary carbon steel, so the heat generated by welding cannot be dissipated quickly, and a large amount of heat gathers in the weld area.
From this, we know that stainless steel welding is suitable for welding with a small heat input welding method, that is, laser welding.
What we offer
1. For the typical joints (butt joint, lap joint, corner joint) of stainless steel car body, the laser welding process optimization and joint performance evaluation work were carried out, and the laser welding process specification (WPS) was formulated;
2. Demonstrate the technological feasibility of laser welding of the main components of the stainless steel car body (side walls, door frames).
Laser-arc hybrid welding
● High adaptability: it is beneficial to reduce the sensitivity to clearance, centering and misalignment, improve weld formation, reduce the number of pores and the control of metallurgical cracks;
● High efficiency: the auxiliary heating of the arc can increase the laser welding speed; the laser guided arc can realize high-speed welding;
● Improve penetration: obtain greater single-pass welding penetration;
● Low cost: lower power laser combined with a certain current arc can obtain the welding penetration of high power level laser.
laser cutting
Traditional CO 2 laser cutting machines can usually only cut stainless steel with a thickness of less than 12mm and aluminum alloys with a thickness of less than 8mm. With the SuperCut cutting technology of Maiman Technology Company, it can easily cut stainless steel and aluminum alloys with a thickness of 20mm.
● Bright surface cutting: few burrs, less roughness, better cutting quality and verticality.
● Variety of plate selection: Standard cutting mode and SuperCut mode can be switched freely, which can achieve high-quality cutting of different thicknesses and different materials with only one device.
● Intelligent cutting system: automatic control of cutting gas, automatic focusing, expandable automatic loading and unloading mechanism and storage unit.
If you have any questions you’d like to ask, feel free to contact us by email.
Pioneer of fiber laser application equipment in China
