What Are Elastic Rail Clips Made Of
Elastic rail clips are usually made of spring steel by a forging process. Forged items are manufactured by hot forging, either in open dies or closed dies. The product takes shape when the metal is formed after being heated to forging temperature. The properties of forged items are considered better than those of parts made by other metal forming processes because of the most uniform microstructure. This uniformity matters because the clip must bend elastically millions of times without cracking.
Spring Steel Grades Used for Clips
The standard spring steel grades for rail clips are 60Si2MnA, 60Si2CrA, 55Si2Mn and 38Si7. The composition of 60Si2MnA is carbon 0.56 to 0.64 percent, manganese 0.60 to 0.90 percent, silicon 1.60 to 2.00 percent and chromium up to 0.35 percent. The 60Si2CrA grade contains chromium of 0.70 to 1.00 percent for improved hardenability, 55Si2Mn carries carbon 0.52 to 0.60 percent with silicon 1.50 to 2.00 percent, and 38Si7 carries carbon 0.35 to 0.42 percent with silicon 1.50 to 1.80 percent. Phosphorus and sulfur are limited to 0.03 percent in all grades.
Hardness and Fatigue Performance
After heat treatment, E-type clips reach a hardness of 44 to 48 HRC and screwed tension clamps reach 42 to 47 HRC. The fatigue life depends on the wire diameter: clips with 18 mm wire withstand 3 million cycles without breaking and clips with 20 mm wire withstand 5 million cycles without breaking. This fatigue performance is the property that keeps the clamping force stable over the service life of the track and prevents premature fracture under repeated wheel loads.
Surface Treatments and Standards
Surface options include plain oiled, oxide black, color painting, hot dip galvanizing and zinc plating. The reference standards are DIN 17221, BS 970 and GB/T 1222 for the spring steel and the finished clips. With strict dimensional control and high quality spring steel, elastic rail clips are kept within the specified ranges to meet customer requirements, providing high performance clamping combined with ease of installation.
Main Clip Models and Parameters
The main clip range includes the Type III clip with 18 mm wire at 0.80 kg, the E1609 with 16 mm wire at 0.43 kg, the E1809 at 0.61 kg, the E1813 at 0.62 kg and the 20 mm series E2001, E2007, E2009, E2039, E2055, E2056 and E2063 at 0.80 kg per piece, all in 60Si2MnA. The range also includes special clips such as the 18 mm Kazakhstan rail clip at 0.58 kg and the 20 mm anti-vandal clip at 0.25 kg.
Why Material Selection Matters
The material and its heat treatment decide whether a clip keeps its elastic range under traffic. A clip made from the wrong steel grade may be too soft and lose clamping force, or too brittle and crack under impact. This is why buyers should always request the chemical analysis, hardness certificate and fatigue test report with each delivery, and why production must use spring steel from certified long term suppliers.
Common Misconceptions
A common misconception is that any round steel bar can be formed into a clip. Only spring steel with controlled composition and heat treatment provides the required elasticity and fatigue life. Another error is believing that a clip is reusable after permanent deformation; once the elastic range is exceeded the clip must be replaced. It is also wrong to judge the quality from the surface color alone, because the mechanical properties come from the material and process, not the finish.
Frequently Asked Questions
What are elastic rail clips made of? They are made of spring steel such as 60Si2MnA, 60Si2CrA, 55Si2Mn and 38Si7, formed by hot forging and heat treated for strength.
Why is forging preferred for rail clips? Hot forging produces the most uniform microstructure, which gives the clip consistent hardness, toughness and fatigue behavior.
What is the composition of 60Si2MnA? Carbon 0.56 to 0.64 percent, manganese 0.60 to 0.90 percent, silicon 1.60 to 2.00 percent and chromium up to 0.35 percent.
What is the fatigue life of rail clips? Clips with 18 mm wire reach 3 million cycles and clips with 20 mm wire reach 5 million cycles without breaking.
Which standards apply to elastic rail clips? The reference standards are DIN 17221, BS 970 and GB/T 1222.
What surface finishes are available? Plain oiled, oxide black, color painting, hot dip galvanizing and zinc plating are available.
