Precision Casting Craftsmanship: Carbon Steel Investment Casting Technology in Railway

Overview

With the high-speed rail transit development today, the carbon steel investment casting technology, with its unique technology advantage, has become an indispensable core technology in railway parts and components manufacturing. This precision casting process, which has been passed down for thousands of years, has been refined by modern engineering technology and is now providing key components with outstanding performance for high-speed trains, heavy-duty freight locomotives and urban rail transit systems.

First, the investment casting process evolution of investment casting process based on the ancient bronze casting techniques, development of the modern industrial system will serve as a model of precision casting.

In the field of railway equipment manufacturing, this process has achieved a leapfrog development from traditional manual production to intelligent production through the deep integration of digital modeling and materials science. The typical process flow includes six major links: 3D modeling → wax mold forming → shell manufacturing → dewaxing and sintering → metal casting → post-treatment. Each stage undergoes strict parameter control. Bogie suspension system components, for example, the manufacturing process to fully demonstrate the essence of modern investment casting technology. Engineers first use finite element analysis software to simulate the stress of the parts. After determining the optimal structural parameters, they use 3D printing technology to make high-precision wax models. Subsequently, a refractory mold was constructed through the seven-layer composite shell process. The carbon steel was melted and cast in a vacuum environment of 1600℃, and finally a precision casting with a grain size reaching ASTM grade 6 standard was formed.

Second, the carbon steel materials engineering suitability of railway equipment has stringent requirements on the properties of materials, material of choice for making carbon steel investment casting.

The improved carbon steel for casting (grades such as ZG230-450 and ZG270-500) achieves a perfect balance among strength, toughness, and casting performance through precise carbon equivalent control (Ceq=0.35- 0.55). Its typical mechanical properties are manifested as tensile strength of 450-600MPa and elongation of 18%-25%, fully meeting the performance requirements for railway components as stipulated by the UIC standard. Compared with traditional sand casting parts, investment casting carbon steel parts has significant advantage: Surface roughness can reach Ra3.2 6.3 mu m, reduce more than 30% of the machining allowance for dimensional accuracy stability in CT5 – level 7, the key matching surface can realize direct assembly density, grain structure fatigue life increase the rate of more than 40% of the complex flow channel structure to realize more than 95%,

Third, typical application scenario, analytical key-module braking system:

Including brake plate brackets, brake levers, etc., investment casting is adopted to ensure uniform stress distribution at each force-bearing point. After the process improvement of the brake lever of a certain type of EMU, the mass dispersion decreased from ±5% to ±1.2%. Suspension components, such as the bogie bolster, axle box spring parts, through the topology optimization design, achieve a 20% of the light. The axle box body cast by the gradient shell technology can have a wall thickness difference of up to 15:1 without generating shrinkage porosity defects. Pin connection fastening systems: hook tongue, buffer after key fittings, such as application of investment casting, shell assembly surface flatness up to 0.05 mm/m, greatly reduce sound probability operation.

Four, build quality control system to ensure the absolute reliability of railway parts, modern investment casting workshop set up four quality protection system:

Raw materials traceability management: from pig iron and scrap steel to build pattern material traceability system process monitoring system: shell roasting temperature curve deviation control within + / – 5 ℃ (NDT) system: Adopt industrial CT + ultrasonic joint detection, defect detection rate 99.97% or higher performance verification service: including 2 million pulses fatigue test, and 40 ℃ low temperature impact test and so on.

Five, the requirements of the sustainable development path in the face of green manufacturing, industry is promote the innovation in three directions:

Digital twin factory: The actual casting parameters and virtual simulation real-time mapping, product rate of 98.5% up to the environmental protection shell material: development of water-based binder and refractory materials, recycle waste heat recycling waste emissions by 60%: Pouring waste heat used for wax mold molding workshop, comprehensive energy consumption reduced by 35% in the “made in China 2025” strategy, driven by carbon steel investment casting technology are high speed evolution in the direction of intelligent, motors, greening. The latest intelligent casting line put into operation by a leading enterprise in rail transit equipment integrates industrial robots, visual inspection systems and adaptive melting equipment, achieving an annual production capacity of 150,000 precision castings. The products have passed the TSI certification and have been exported to the EU market.

The old and the young technology, through continuous technical innovation and process optimization, is China’s high-speed rail this national card provides the solid metal skeleton. From snow-capped plateaus to tropical islands, countless carbon steel components formed by investment casting technology are quietly fulfilling their mission of safety protection on China’s vast railway network, witnessing the strength and responsibility of “Made in China”.

Supplier

Luoyang Fonyo Heavy Industries Co., Ltd,founded in 1998,is a manufacturer in cast railway parts.Our factory covers an area of 72,600㎡, with more than 300 employees, 32 technicians, including 5 senior engineers, 11 assistant engineers, and 16 technicians.Our production capacity is 30,000 tons per year. Currently, we mainly produce casting, machining, and assembly for locomotive,railcar,high-speed trains, mining equipment,wind power,etc.Our products have been exported to Russia, the United States, Germany, Argentina, Japan, France, South Africa,Italy and other countries.
Contact:Cathy
Email:sales@railwaypart.com
Mobile:008615515321683