of the rail
2021-06-16
Rail track They are categorized into used rails and scrap rails. Used rails are reusable materials typically supplied in fixed lengths. Their application is generally determined by railway authorities based on the degree of rail wear, allowing them to be repurposed. Companies that commonly utilize used rails include coal mines and other enterprises requiring rail installation in mine tunnels. Additionally, the installation of gantry cranes and overhead cranes also necessitates rail laying; opting for used rails can significantly reduce costs while delivering comparable performance. Scrap rails, on the other hand, can only be processed as heavy-grade scrap steel by steelmaking enterprises.
Chemical Composition and Properties of Ordinary Steel Rails Section 1: Properties of Steel Commonly used metallic materials are generally classified into two categories: nonferrous metals and ferrous metals. Steel products represent the most widely used type of ferrous metal. Steel is an alloy composed primarily of two elements: iron and carbon. Iron–carbon alloys with a carbon content of less than 0.02% are referred to as commercially pure iron. Physical and chemical properties: The tendency of a material to expand when heated is known as thermal expansion, and the linear coefficient of thermal expansion is typically used as the quantitative measure of this phenomenon. Different grades of steel exhibit different coefficients of linear thermal expansion; moreover, this coefficient increases with rising temperature. The thermal conductivity of steel is also referred to as its heat-conductivity coefficient. Alloying elements in steel influence its thermal conductivity, with stainless steels generally having lower thermal conductivity than low-carbon steels and low-alloy steels. The magnetic permeability of steel is called its magnetic-permeability coefficient. With the exception of single-phase austenitic steels, which are nonmagnetic, all other steels are magnetic.
After rail welding, medium-frequency induction normalizing heats the rail by inducing eddy currents in the rail steel due to its magnetic permeability. Electrical conductivity refers to the ability of conductive steel at temperatures above 770°C to carry electric charge. The resistivity coefficient is commonly used as an indicator for measuring electrical conductivity: the higher the resistivity of steel, the poorer its conductivity and the more heat generated when current passes through it. Resistance welding or flash butt welding of steel relies on the heat produced by the high resistance at the end faces of the workpieces. The ability of steel to resist oxidation under specific temperature and environmental conditions is known as oxidation resistance. Steel with poor oxidation resistance is easily oxidized by oxygen in the surrounding medium at high temperatures, forming an oxide scale that gradually spalls off and leads to material damage. Heat-resistant steels exhibit good oxidation resistance, while stainless steels have the best oxidation resistance. Mechanical properties refer to a steel’s ability to resist deformation and fracture under specified temperatures and external loads; these are also termed mechanical performance.
Conventional mechanical properties primarily include strength, ductility, hardness, and toughness; high-temperature mechanical properties further encompass creep resistance, long-term and instantaneous strength, and thermal fatigue performance; while low-temperature mechanical properties include the ductile–brittle transition temperature, among others. Strength and ductility are further classified into static strength and fatigue strength. Static strength refers to a steel’s ability to resist deformation and fracture under slow, static loading. Fatigue strength, on the other hand, is the capacity of steel to withstand numerous cycles of cyclic loading without developing cracks or fracturing.
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Address: No. 1, Xinning West Road, Group 6, Ningtong Residence, Jiang’an Town, Rugao City, Jiangsu Province
Nantong Longyu Rail Equipment Co., Ltd.
Contact: General Manager Wu
Address: No. 1, Xinning West Road, Group 6, Ningtong Residence, Jiang’an Town, Rugao City, Jiangsu Province
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