A Comprehensive Understanding of GB Steel Rails

Rails are the main components of railway tracks. Their function is to guide the wheels of locomotives and vehicles forward, bear the huge pressure of the wheels, and transmit it to the sleepers. Rails must provide a continuous, smooth and least resistant rolling surface for the wheels. In electrified railways or automatic block sections, rails can also be used as track circuits. Rails are rolled from carbon-killed steel smelted in open-hearth furnaces and oxygen converters, and their purpose is to withstand the operating pressure and impact load of locomotives and vehicles.

The GB rail standard stipulates that two types of marks are required on the waist of the rail, namely rolling marks and hot stamping marks. Other marks are also stipulated, such as painting on the rail ends and sticking labels.

Protruding mark: The order of the convex mark rolled on the waist of one side of the rail is: manufacturer mark - rail type (such as 60 represents 60kg/m); rail grade (such as u75vG, u7lMnG); manufacturing year (the last two digits of the rolling year), month, (such as 04 represents the rolling year of 2004, and III represents rolling in March).

Concave mark: The order of the hot-embossed concave mark on the waist of the other side of the rail is: steel plant code - production year - furnace number - continuous casting stream number - continuous casting billet number - rail sequence number - shift number. The hot-embossed marks of each steel plant are not exactly the same.

The cross-sectional shape of the rail adopts an I-shaped section with the best bending resistance, which consists of three parts: rail head, rail waist and rail bottom. The cross section of the rail is an I-shaped section.

Generally, it is classified by the mass of rail per linear meter (kg/m) after rounding, and can be divided into three types: crane rail (crane rail), heavy rail and light rail:

① Crane rail is divided into four types: QU120/QU100/QU80/QU70, and the material is generally manganese steel. The largest single weight is QU120, which can reach 118kg/m.

② Heavy rail: According to the type of steel used, it is divided into: ordinary manganese-containing rail, copper-containing carbon steel rail, high-silicon copper-containing steel rail, copper rail, manganese rail, silicon rail, etc. Originally, there were mainly three types: 38kg, 43kg, and 50. Later, the new standard GB/T2585-2007 was promulgated in 2007. In addition to 38~50kg/m, two new types of heavy rails, 60kg/m and 75kg/m, were added.

③ Light rail: There are mainly different rail types such as 9, 12, 15, 22, and 30kg/m. Light rail is also divided into two types: national standard (GB) and departmental standard (YB Metallurgical Ministry standard). The above are several models of GB, and the models of YB are: 8, 18, 24kg/m, etc.

Heavy rail: Rails with a nominal weight of more than 30kg per meter. Train rails and crane rails are both heavy rails. Train rails are used to lay railways. They must withstand the pressure, impact load and friction during train operation, and require sufficient strength and a certain toughness. The quality requirements are strict. In addition to ensuring its chemical composition, it is also required to test mechanical properties, drop hammer tests and acid leaching low-magnification structures.

Light rail: Mainly used for laying temporary transportation lines and light locomotive lines in forest areas, mining areas, factories and construction sites.

Crane rails: It has a lower height, larger head width and waist thickness, and is used to lay crane and trolley tracks.