Types, Production, and Maintenance of National Standard Rails
- What are the main types of national standard steel rails?
There are various types of national standard steel rails. Common ones include 43kg/m, 50kg/m, 60kg/m, 75kg/m, etc. The approximate mass per meter of different types of steel rails is different, which determines the differences in their bearing capacity and application scenarios. The 43kg/m steel rail is often used in some branch railways or lines with relatively low bearing requirements; the 50kg/m steel rail is widely used and is common in ordinary railways; the 60kg/m steel rail is widely used in railway trunk lines because it can better withstand the weight of trains and the impact force during operation; the 75kg/m steel rail is generally used in heavy-haul railways and other lines with extremely high requirements for the strength of steel rails.
- What is the standard length of national standard steel rails?
The standard length of steel rails in China varies according to types. The length of 43kg/m steel rail is 12.5m or 25m; the length of steel rails above 50kg/m has three types: 25m, 50m, and 100m. Among them, for seamless lines, 100m steel rails (100-meter fixed-length rails) produced by steel mills are generally transported to the rail welding factory to be welded into 500m long rails, and then transported to the construction site to be welded into the required length. Such length settings are not only convenient for transportation and construction but also can meet the laying requirements of different railway lines, ensuring the stability and continuity of railway tracks.
- Which enterprises produce national standard steel rails?
There are many well-known steel rail production enterprises in China, mainly including Pangang Group Co., Ltd. (referred to as Pangang), Anshan Iron and Steel Group Co., Ltd. (referred to as Ansteel), Baotou Iron and Steel (Group) Co., Ltd. (referred to as Baotou Steel), Wuhan Iron and Steel (Group) Corporation (referred to as Wisco), and Handan Iron and Steel Group Co., Ltd. (referred to as Hangang), etc. These enterprises have advanced production technologies and equipment and have the ability to produce national standard steel rails on a large scale, providing a solid material guarantee for domestic railway construction.
- What is the production process of national standard steel rails?
The manufacture of national standard steel rails mainly includes smelting, billet, rolling, and finishing processes. First is smelting. After the hot metal from the blast furnace is pretreated, it enters the converter, and then goes through processes such as argon blowing in the ladle and aluminum-free deoxidation. In the billet stage, ingots can be cast by die-casting and then hot-rolled into billets, or continuous casting billets can be directly used. Then comes hot rolling. The billets are heated in a pusher-type reheating furnace, rolled by a cross-type rolling mill, cut to length by a hot saw, automatically printed, and finally cooled on a pusher-type cooling bed. In the finishing stage, slow cooling is required. It is straightened by a horizontal-vertical combined straightening machine, then the four-side pressure straightening of the rail ends is carried out, followed by on-line ultrasonic flaw detection. Finally, it is processed by a saw-drilling combined machine tool. Some steel rails also need to be quenched in the cap-shaped shape at the rail ends. After being inspected by workers and passing the inspection, they are put into storage.
- How to maintain national standard steel rails during use?
The maintenance of national standard steel rails during use is of great importance. Daily visual inspection should be carried out to check for obvious defects such as wear and cracks. Regularly conduct flaw detection on the steel rails, using technologies such as ultrasonic to detect whether there is internal damage. For severely worn parts, grinding should be carried out in a timely manner to restore the surface flatness of the steel rails and reduce the wear and impact between the wheels and the steel rails. At the same time, the fastener system of the track should be kept tight to prevent the displacement of the steel rails. In addition, attention should be paid to the anti-corrosion treatment of the steel rails, especially in humid environments with corrosive media. The service life of the steel rails can be extended by applying anti-corrosion coatings.