Análise de requisitos técnicos para fundição de rodas de trens ferroviários

As a core component of the railway transportation system, a qualidade das rodas dos trens afeta diretamente a segurança, eficiência, e vida útil dos trens. Rodas fundidas, due to their excellent comprehensive mechanical properties and high economic efficiency, have become the preferred choice in heavy-haul and railway fields. No entanto, their manufacturing process involves multiple precise and strict technical requirements, including material selection, projeto estrutural, processo de fundição, tratamento térmico, e testes não destrutivos, entre outros. Only through strict control throughout the entire process can the high reliability and long lifespan of the wheels be guaranteed during actual operation.

EU. Material Requirements

1.1 The material of the wheels must have high strength, dureza, e resistência ao desgaste. Ao mesmo tempo, the manufacturers also consider good toughness and fatigue resistance. Atualmente, high-carbon low-alloy steels are widely used, such as the R7, R8, R9 series in European standards, or CL60, ER8, ER9 in Chinese standards. The carbon content is typically between 0.55% e 0.65%, with the addition of silicon, manganês, cromo, and other alloy elements to enhance hardenability and comprehensive mechanical properties.

1.2 In addition to strictly adhering to chemical composition standards, the microstructure is also crucial. The ideal microstructure should be fine lamellar pearlite. So it can avoid the presence of network-like pre-eutectic ferrite or large carbides, as these would significantly affect the wheel’s wear resistance and resistance to contact fatigue. Portanto, from steelmaking to casting, every step must strictly control the material’s purity, gas content, and non-metallic inclusions.

II. Structural Design and Dimensional Accuracy

2.1 The structural design of the wheels must balance mechanical rationality, estabilidade operacional, and manufacturing feasibility. It mainly consists of the rim, raios, and hub. A borda, which directly contacts the rails, must strictly comply with the profile standards set by the country or the International Union of Railways (UIC) for the tread contour, altura da flange, and thickness to ensure guiding performance through curves and reduce derailment risks.

2.2 The spokes are supporting structure connecting the rim and the hub. So they need to have good bending resistance and fatigue resistance. Common designs include S-shaped and wavy shapes, which can effectively buffer vibrations and impacts during operation.

2.3 In terms of dimensional accuracy, the key dimensions of the finished wheels, such as diameter, espessura da flange, and rim width, typically need to be controlled within ±0.5 mm. So it can ensure correct fit with the rails and smooth train operation.

III.  Casting Process Control

3.1 Casting is the fundamental step that determines the performance of the wheels. Atualmente, gravity casting or centrifugal casting are the mainstream methods. Centrifugal casting is widely adopted due to its ability to significantly increase metal density and mechanical properties. Durante o processo de vazamento, the temperature of the molten steel (generally controlled between 1480°C and 1520°C) must be strictly controlled to avoid defects such as coarse grains due to excessively high temperatures or insufficient filling due to low temperatures.

3.2 Além disso, parameters such as mold design and preheating, pouring speed, and centrifuge speed all need to be precisely controlled. Modern wheel casting often uses computer simulation technology to predict potential problems such as shrinkage cavities, porosidade, or hot cracks during the casting process, thereby optimizing the process and improving the first-pass qualification rate.

4. Processo de tratamento térmico

4.1 Depois de lançar, the wheels must undergo appropriate heat treatment to adjust their microstructure and properties, mainly including normalizing, têmpera, e têmpera. Normalizing aims to refine grains and eliminate casting stresses; quenching obtains a high-hardness martensitic microstructure through rapid cooling; and tempering reduces brittleness and improves toughness, stabilizing the microstructure.

4.2 The heating rate, holding temperature and time, cooling medium and rate during heat treatment must be set according to the wheel material and size. Por exemplo, some high-strength wheels use isothermal quenching to obtain a lower bainite microstructure, achieving both high hardness and good toughness.

V. Non-destructive Testing and Quality Verification

To ensure that each wheel is free of internal defects, comprehensive non-destructive testing must be conducted. Commonly used methods include ultrasonic testing (EUA), teste de partículas magnéticas (MT), and eddy current testing (ET). Ultrasonic waves can effectively detect internal cracks, inclusões, shrinkage cavities and other defects, while magnetic particle and eddy current testing are mainly used for identifying surface and near-surface defects.

In addition to non-destructive testing, destructive tests should also be conducted on samples from the same batch of wheels, including tensile tests, impact tests, hardness tests and metallographic analysis, to ensure that their mechanical properties and microstructure meet the standard requirements.

VI. Environmental Adaptability and Durability Requirements

Wheels need to maintain stable performance under different climatic conditions, track conditions and operating loads. Por exemplo, in cold regions, they need to have low-temperature impact toughness; in high-speed operation environments, they need to have excellent resistance to thermal damage and rolling contact fatigue. Portanto, in addition to the control of the above manufacturing processes, their durability should also be verified through bench tests and actual operation evaluations.

Fornecedor

Luoyang Fonyo Indústrias Pesadas Co., Ltda,fundada em 1998, é fabricante de peças fundidas ferroviárias. Nossa fábrica cobre uma área de 72.600㎡, com mais de 300 funcionários, 32 técnicos, incluindo 5 engenheiros seniores, 11 engenheiros assistentes, e 16 técnicos.Nossa capacidade de produção é 30,000 toneladas por ano. Atualmente, produzimos principalmente fundição, usinagem, e montagem para locomotiva, vagão, trens de alta velocidade, equipamento de mineração,energia eólica,etc..
Somos o fornecedor de peças ferroviárias para CRRC(incluindo mais de 20 empresas filiais e subsidiárias da CRRC),Máquinas de Engenharia Gemac,Grupo Sany, Indústrias Pesadas Cíticas,etc.. Nossos produtos foram exportados para a Rússia, os Estados Unidos, Alemanha, Argentina, Japão, França, África do Sul,Itália e outros países em todo o mundo.
Informações de contato:
E-mail:[email protected]
Móvel:008615515321683