Since 1767, the steel rail has experienced more than 230 years, with the development of railway technology, rail cross section has also experienced from the plate to the T shape and U shape process, know that in 1864 only finally fixed to the.
According to different purposes, the modern rail can be divided into three categories:
1, for mine railway light rail, there are 8kg/m, 9 kg/m, 12 kg/m, 18 kg/m, 22 kg/m, 24 kg/m, 30 kg/m eight.
2, for passenger and freight rail with heavy cabinets, China railway use of heavy rail are mainly five kinds of 38 kg / m, 43 kg / m, 50 kg / m, 60 kg / m, 75 kg / M. In addition to the transformation of the rail track, there are 50AT, 60AT two.
3, the supply of crane rail crane rail, there are currently QU70, QU80, QU100, QU120 four specifications.
According to the different materials used in the rail, and can be divided into high quality, is divided into three kinds of high-quality carbon rail, alloy rail and the whole field of heat treatment:
1, high-quality carbon rail is mainly carbon, manganese content to improve strength, improve human nature, sulfur, phosphorus content control in the following 0.030%, the main brands are U74, U71Mn.
2, alloy rail is is to carbon rail d, adding proper amount of alloy elements such as V, Ti, CRr, Mo, so as to improve the strength and toughness of rail, alloy rail in our country is re NB rail, RE-Cr rail and V-Ti rail, the main brands are U76RENB, U75V, U76CrRE.
3, full length heat treatment rail is more than two rail for rail through the heat treatment process of heating and cooling control, improve the internal organizational structure, grain refinement, forming pearlite, which acquired the rail of high strength and high toughness.