The E-type elastic rail clip is a key component widely used in railway fastening systems. It firmly secures the rail to the sleeper, ensuring track stability and operational safety. Manufactured from high-strength spring steel 60Si2MnA, this clip undergoes precise heat treatment, providing excellent fatigue resistance and elasticity to withstand high-frequency vibrations and impact loads from passing trains. The oxide black surface treatment enhances corrosion resistance while preventing surface wear and rust, making the clip suitable for various climatic conditions, including humid and coastal railway lines.
Material Properties of 60Si2MnA Spring Steel
60Si2MnA is a silicon-manganese spring steel defined in the Chinese standard GB/T 1222. Its chemical composition is carbon 0.56 to 0.64 percent, silicon 1.60 to 2.00 percent and manganese 0.60 to 0.90 percent, with low limits for chromium, phosphorus and sulfur. After quenching and tempering, the steel achieves high elastic limit, high yield strength and excellent fatigue resistance, which are the essential requirements for elastic rail clips working under alternating repeated stress. The same steel family is also used for other spring components such as leaf springs and suspension springs.
Hardness and Fatigue Performance
E-type elastic rail clips made of 60Si2MnA are heat treated to a hardness of 44 to 48 HRC, which provides the optimum combination of spring force and toughness. Under fatigue testing, clips of 18 mm wire diameter withstand 3 million cycles without breaking, while clips of 20 mm diameter withstand 5 million cycles without breaking. The toe load of common E-type clips is at least 950 kg, ensuring that the rail foot is firmly pressed onto the pad and the sleeper under traffic.
Common Models and Dimensions
| Model | Wire diameter | Weight | Material | Hardness |
|---|---|---|---|---|
| E1609 | 16 mm | 0.43 kg/pc | 60Si2MnA | 44-48 HRC |
| E1809 | 20 mm | 0.61 kg/pc | 60Si2MnA | 44-48 HRC |
| E1813 | 18 mm | 0.62 kg/pc | 60Si2MnA | 44-48 HRC |
| E2001 | 20 mm | 0.80 kg/pc | 60Si2MnA | 44-48 HRC |
| E2009 | 20 mm | 0.80 kg/pc | 60Si2MnA | 44-48 HRC |
| E2055 | 20 mm | 0.80 kg/pc | 60Si2MnA | 44-48 HRC |
In addition, Type III clips of 18 mm diameter are available according to the GB standard, with a weight of about 0.80 kg per piece. Other models such as E2007, E2039, E2056 and E2063 share the same material and hardness range. Special clips can be manufactured against customer drawings.
Oxide Black Surface Treatment
The oxide black treatment creates a thin magnetite layer on the clip surface, giving a uniform black appearance. This layer improves the corrosion resistance of the spring steel, prevents surface wear and rust, and increases the friction between the clip and other fastening components, which helps to maintain consistent clamping performance. For more aggressive environments, color painting, hot-dip galvanizing or zinc plating can be specified instead.
Applications, Inspection and Maintenance
E-type clips are used with base plates, rail pads, insulators and screw spikes to form a complete fastening system on concrete sleepers. They are suitable for various rail sections and are widely applied on main lines, secondary lines, mining railways and urban transit systems in many countries, including Southeast Asia, South Asia, the Americas and other regions. The casting insert of the fastening system is often made of ductile iron such as QT450-10, the insulator of PA6 reinforced with glass fiber, and the rail pad of rubber.
During track inspection, check E-type clips for cracks, rust, loss of toe load and displacement from the correct position. Damaged clips must be replaced promptly, and clips should be handled with correct tools to avoid impact damage. In coastal and industrial areas, inspect the oxide black layer for breakdown and consider upgrading to hot-dip galvanized clips where corrosion is severe.
Frequently Asked Questions
What is 60Si2MnA steel? It is a silicon-manganese spring steel defined in GB/T 1222, with carbon 0.56 to 0.64 percent, silicon 1.60 to 2.00 percent and manganese 0.60 to 0.90 percent.
What hardness do E-type clips have? E-type clips are heat treated to 44 to 48 HRC for the best combination of spring force and toughness.
What is the fatigue life of E-type clips? Clips of 18 mm diameter withstand 3 million cycles without breaking, and clips of 20 mm diameter withstand 5 million cycles.
Why is oxide black treatment used? It improves corrosion resistance, prevents surface wear and rust, and maintains consistent clamping performance in humid and coastal climates.
What toe load do E-type clips provide? Common E-type clips provide a toe load of at least 950 kg, pressing the rail foot firmly onto the pad.
Can E-type clips be made to special drawings? Yes, clips with special dimensions or higher strength materials can be manufactured against customer drawings and requirements.
