Railway clips are usually made of forged spring steel, which is manufactured through a hot forging process. Forged railway clips are considered better than clips made by other metal forming methods because the forging process produces a uniform microstructure that improves elasticity, toughness and fatigue resistance.
Manufacturing Process
The elastic rail clip manufacturing process follows these steps in sequence: shearing, heating to forging temperature, forming, hardening, tempering, inspection and packing. Each step is controlled so that the finished clip meets the required dimensions, hardness and clamping performance.
Steel Grades and Properties
Common steel grades for elastic rail clips are 60Si2MnA, 60Si2CrA, 55Si2Mn and 38Si7. The table below summarizes the typical requirements for E-type clips and tension clamp clips.
| Property | E-Type Clip | Tension Clamp Clip |
|---|---|---|
| Hardness | 44-48 HRC | 42-47 HRC |
| Fatigue life, 18 mm bar | 3 million cycles without breaking | 3 million cycles without breaking |
| Fatigue life, 20 mm bar | 5 million cycles without breaking | 5 million cycles without breaking |
| Standards | DIN 17221, BS 970, GB/T 1222 | DIN 17221, BS 970, GB/T 1222 |
Heat Treatment.
Hardening and tempering are the key heat treatment steps for rail clips. Hardening gives the clip its high hardness and elasticity, while tempering adjusts toughness so that the clip can absorb repeated impact without brittle failure. Correct heat treatment is the basis of the specified 42 to 48 HRC hardness range.
Surface Finishes
Plain oiled surface
Oxide black finish
Color painting
Zinc plating and hot-dip galvanizing
The surface finish is selected according to the climate and the corrosion protection requirement of the project.
Role of Elastic Clips in the Track
Railway elastic clips are essential elastic fasteners in the track structure. They press the rail base onto the pad and sleeper, maintain the gauge, absorb impact and vibration, and keep the fastening force stable under long-term repeated loading. Clip failure would allow rail creep and gauge widening, so material quality and fatigue life are critical.
Inspection and Quality Assurance
Finished clips are inspected for hardness, dimensional accuracy and surface defects, and fatigue testing is performed to confirm the specified life. Traceability is maintained from the raw material batch to the finished packing so that any quality issue can be traced back to the production step.
Frequently Asked Questions
What material are rail clips made of? Rail clips are usually made of forged spring steel such as 60Si2MnA, 60Si2CrA, 55Si2Mn and 38Si7.
Why is hot forging used for rail clips? Hot forging creates a uniform microstructure that gives better elasticity, toughness and fatigue resistance.
What is the hardness of a rail clip? E-type clips are 44 to 48 HRC and tension clamp clips are 42 to 47 HRC.
What is the fatigue life of a rail clip? n 18 mm bar clip passes 3 million cycles and a 20 mm bar clip passes 5 million cycles without breaking.
Which standards apply to rail clip materials? DIN 17221, BS 970 and GB/T 1222 are commonly referenced for spring steel material and testing.
