Railway Axle Housing as Core Load-bearing Component to Locomotive

Introduction of Railway Axle Housing

The axle housing ( axle box) of the rail vehicle, as the core load-bearing component of the bogie system of the rail vehicle, its design and material selection are directly related to the safety, stability and service life of the train operation.

Material and Process Features of Modern Railway Axle Housing

The axle box is made with high-strength alloy cast steel (such as ZG25MnCrNiMo) and nodular cast iron (QT500-7), two kinds of base material, supplemented by differential heat treatment process to meet the demand of different working conditions. Among them, cast steel structures are widely used in heavy-duty freight transportation and high-speed EMU fields due to their excellent impact toughness (impact energy at room temperature ≥35J) and tensile strength (≥600MPa). During the casting process of the box body, resin sand precision forming technology is adopted, combined with 3D scanning reverse detection, to ensure that the dimensional accuracy of the complex inner cavity structure is controlled within ±0.3mm.

In view of the development trend of lightweight, new aluminum alloy axle box body (AlSi7Mg – T6) has gradually been pilot applied in urban rail vehicles. The aluminum alloy box formed by the vacuum die-casting process is 40% lighter than the traditional cast steel part. Combined with anodic oxidation surface treatment (film thickness 20-25μm), the corrosion resistance is improved by more than three times while maintaining a yield strength of 450MPa. It is worth noting that in an extremely low-temperature environment (-40℃), the material needs to pass the Charpy V-notch impact test to verify its low-temperature toughness.

material	High-strength alloy cast steel (such as ZG25MnCrNiMo) and ductile iron (QT500-7)
material and characteristics	strength of extension	≥600MPa
	dimensional accuracy of the inner cavity structure	within ±0.3mm
Environmental dimension considerations	Particle barrier efficiency	99.97%（test in EN 15085 standard）
	adaptive temperature	from -40~150℃

 The Structural Design and Technical Characteristics of Railway Axle Housing

Topology optimization design was used to construct variable cross-section box structure, key bearing area wall thickness of 25 mm, and the stress section thinning to 12 mm to achieve maximum stiffness weight ratio. Finite element analysis shows that the maximum stress point of this structure under a longitudinal impact load of 300kN is 20% lower than the allowable value of the material.

(1)Composite seal system: configuration labyrinth mechanical seal with double protection, fluorine rubber lip seal with the compression type sealing ring (compression ratio 18 + / – 2%), which can effectively cut off grade PM10 level fine dust. The IP67 protection level ensures a maintenance-free cycle of 500,000 kilometers for the bearing lubrication system.

(2)Intelligent monitoring integration: Reserve an embedded sensor installation base, supporting real-time monitoring of multiple parameters such as temperature (-40 to 150℃), vibration (0.5 to 10kHz frequency response), and stress (±2000με range). The data sampling rate can reach up to 10kHz, providing a technical foundation for predictive maintenance.

Function Implementation and System Integration of Railway Axle Housing

As the wheel/rail system of “mechanical conversion hubs” bears the multi-dimensional function bearing axle box body: static, dynamic load transfer: The vertical direction bears the self-weight of the bogie (typical value 8-12 tons) and the dynamic wheel-rail impact force (peak can reach three times the axle weight), as well as the centrifugal force when the lateral transmission curve passes through (under the maximum acceleration condition of 0.3g).

(1)Motion constraint control: The longitudinal/lateral displacement elastic constraint of the wheelset is achieved through the positioning node (rubber joint stiffness 25±3kN/mm) to ensure stability loss at the critical speed.

(2)Thermal management center: The heat dissipation fin design of the box body keeps the temperature rise of the bearing within ΔT≤35℃ (under a continuous working condition of 80km/h) and is combined with thermal grease (3.5W/m·K) to enhance the heat conduction efficiency.

(3)Fault isolation barrier: When the binding of the bearings, the mechanical weak link of the preset of the (shear pin) directional rupture, prevent expanding hot shaft failure as EN15085 welding system certification and ISO/TS22163 the in-depth implementation of rail transit industry standards, Modern axle box manufacturing has established a full-process quality control system covering material metallurgy (cleanliness control [O]≤30ppm), precision casting (CT8 grade accuracy), and intelligent detection (industrial CT defect identification accuracy 0.2mm).

Future Development of Railway Axle Hosuing

In the future, with the maturation of metal matrix composites (SiC particle-reinforced aluminum matrix composites) and 3D printed conformal cooling channel technology, the new generation of axle box bodies will achieve breakthroughs in lightweight (with a target weight reduction of 50%) and functional integration.

Package of Railway Axle Box

Polybag+Carton box+Wooden case/Pallet, according to customer’s request

Company Profile

Luoyang Fonyo Heavy Industries Co., Ltd. was founded in 1998, covers an area of 72,600㎡, with more than 300 employees, 32 technicians, including 5 senior engineers, 11 assistant engineers, and 16 technicians. It has been rated as Luoyang Engineering Technology Center, Luoyang Technology R&D Center, and National High-tech Enterprise for many times.
Our production capacity is 30,000 tons per year. Currently, we mainly produce cast steel, cast iron (gray iron, ductile iron, etc.), processing of finished product and component assembly.the products have been exported to Russia, the United States, Germany, Argentina, Japan, France, South Africa,Italy and other countries.

FAQS

Q1: Are you a manufacturer or trading company?
A:We are a manufacturer. Our company was founded in 1998, with nearly 30 years in casting industry, a total area of 72,600㎡, with a factory building area of 51,000㎡.
Q2. What are your main products?
A: We primarily focus on steel casting, iron casting, finished product machining, and component assembly production.
Q3: How precision can you produce casting parts?
A: We have the capability of producing casting parts with different casting processes. The production is strictly comply with ISO 9001, ISO 14001 and ISO45001,EN15085, IRIS.
Q4. Can you produce according to the samples?
 Yes, we can produce by your samples or technical drawings. We can build drawings for you after we get your samples too.
Q5: How do you do Quality Control before delivery?
A: Quality inspection is a very important factor to guarantee the quality of steel casting parts. We follow 3 times of inspection during the whole production process. And we will provide material testing report, dimensional testing report, and mechanical properties testing report to our clients before delivery.

It you are interested in any products,please feel free to contact us.
Contact:Cathy Xu
Email:sales@railwaypart.com
Mobile:008615515321683