How are the rails classified?
“#50rail, #60rail…” These words are often heard from the mouths of railway people to describe rail models. So how are these rails classified?
Classification of rails
The type of rail is expressed in kilograms of rail mass per meter of length. With the increase of train speed and axle load, the improvement of stability requirements, the improvement of production and manufacturing processes and other factors, the classification of rails has become more and more detailed.
Sort by weight
The types of rails are usually distinguished by weight. For example, the #50 rail we often say refers to the rail with a weight of 50kg/m, and so on, there are #38 rails, #43 rails, #50 rails, #60 rails, #75 rails, etc. Among them, rails with #43 rails and above are generally called heavy rails.
Classified by manufacturing process
It is mainly divided into hot rolled rail and heat treated rail. In fact, the rail is produced by the hot rolling process, the heat treatment rail is in the hot rolling molding of the rail for heat treatment again, divided into online heat treatment and offline heat treatment of two kinds, online heat treatment is already the mainstream, more energy saving and more efficient. In addition, the standard rail produced has a fixed length, called the length of the rail, generally 12.5 meters, 25 meters, 100 meters, the longer the rail the less the joint in the future.
Classification by strength
Rail is a complex and alloy, in addition to the main composition of iron (Fe), there are five elements, carbon (C), manganese (Mn), silicon (Si), phosphorus (P), sulfur (S), of course, there will be some decisive role of trace elements vanadium (V), chromium (Cr), and some rare earth elements, etc., these elements fuse with each other and the manufacturing process is different. Created different physical properties of the rail, of which the most important are three: strength, hardness, toughness (generally with elongation after breaking to examine), the three are related to each other, the most important is the strength, so there is also a method to classify the rail according to the strength level. You will see 780Mp, 880Mp, as high as 1450Mp and so on, according to different needs to choose. Generally speaking, the strength of the subway rail is between 880 and 1180Mp.
Classification by rail use
Classification according to the use is basically the most common practice, and now all kinds of rail transit construction is in the ascendance, and the uses of steel rails are also diverse.
At present, high-speed rail and ordinary rail are basically 60 rails in the station (50 rails in some stations), and the main line is also 60 rails, but the rail requirements of high-speed rail are very high, and the flatness and size requirements of each part are higher.
Rails are the main components of railway tracks, ensuring safe, smooth and fast train transportation.
