About the material of rails

The chemical composition of rails not only contains the five basic elements in steel - carbon (C), silicon (Si), manganese (Mn), sulfur (S) and phosphorus (P), but also incorporates alloying elements such as chromium (Cr), vanadium (V), niobium (Nb), and other residual elements in steel. In terms of naming, rail steel usually starts with the letter "U", which stands for rail steel, which is the second letter of the Chinese pinyin of the word "rail" GUI. The number part indicates the average carbon content, and the subsequent letters reveal the alloying elements. For example, U75V means that its average carbon content is 0.75% and it has been alloyed with vanadium.

The strength level of rails is an important indicator to measure their load-bearing capacity. According to different strength standards, rails can be divided into multiple grades. For example, 780MPa-grade rails include types such as Japanese JIS60 and Chinese U74; 880MPa-grade rails include UIC900A and Chinese U71Mn. As the strength grade increases, the wear resistance and load-bearing capacity of the rails will also increase accordingly. Rails above 980MPa, such as the US AREMA ordinary rails, China U75V hot-rolled rails, and U77MnCr hot-rolled rails, usually have excellent wear resistance and strength. Rails of 1080MPa and above are considered wear-resistant rails or high-strength rails, such as EN320Cr alloy rails, Japan HH340 online heat-treated rails, etc. Higher-strength 1180MPa and 1280MPa heat-treated rails are suitable for high-strength requirements in special environments.

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