The History of Rail
The history of China railway began in the last years of qing dynasty.
Currently recognized the earliest existing Hanyang iron factory rail, is the Chinese Iron and Steel Museum collection of 1899 "Hanyang made" rail.
This was the time of 1902 in Shaanxi Lueyang found the Qing Dynasty railroad rail.
The Story of Rail
Welding machine through the resistance heating method, the two rails adjacent to each other temperature rise to more than 1000 degrees, and then squeeze welding. At present, the use of 500 meters long seamless rail, in fact, by the five 100 meters long rail welded in the welding workshop.
Welding a good rail through the appearance of flatness fine straightening, fine grinding, weld nondestructive testing, welding joints need to enter the flaw detection process, the welding head to scan the internal diagnosis, like a doctor to the patient to do "B super".
Finished Products Placed
The hoisting rails, which are too long to look like soft "noodles", will soon be embarked on a new "journey".
This is the transport of 500 long rail dedicated long rail trains, long rail is so be transported to the construction site.
Long Rail Replacement Site
Construction Site and the First to Cut the Rail
The workers will be the new rail down, and then the old rails using the track car recycling to long rail car.
The use of large-scale road maintenance machinery (welding rail) on the joint welding and grinding.
Popular science knowledge: 500 meters long rail railroad is afraid of "hot" (thermal expansion and contraction)
Life of the body of the thermal expansion and contraction, we all know, the same, the railroad rail is also the case.
Railway summer is how to deal with 500 meters rail hot expansion?
Summer temperatures are high, the railway line workers will rush to the scene, the rail level, level, direction and other equipment to check the state.
When the rail deviation to a certain distance to a certain distance, the staff near the water, the cooling of the rails and other technical treatment.
In the watering cooling is invalid, the workshop repair group with oxygen cutting equipment to remove the expansion part, that is, the rails for stress relief treatment.
Emergency release, the cutting position on the aluminum heat welding, so the summer rail is no longer afraid of heat.
Knowledge: Classification of Rails
Since the invention of the railroads in 1767, it has gone through more than 230 years. With the development of railway technology, the section of the rail has experienced the process from flat to T-shaped to U-shaped, and it is known that it is finally fixed in 1864.
Depending on the use, modern rails can be divided into three categories:
1. For the mine rail with light rail, 8kg / m, 9 kg / m, 12 kg / m, 18 kg / m, 22 kg / m, 24 kg / m, 30 kg / m eight.
2. For the passenger and cargo railway with the heavy cabinet, the use of heavy rail rails in China are 38 kg / m, 43 kg / m, 50 kg / m, 60 kg / m, 75 kg / m five. There are also changing the track with the track, there are 50AT, 60AT two.
3. The supply of crane rails with the crane rail, there are QU70, QU80, QU100, QU120 four specifications.
Rail according to the choice of different materials, but also can be divided into high quality, divided into high-quality carbon rail, alloy rail and the whole field of three kinds of heat treatment:
1. High-quality carbon tracks are mainly carbon and manganese elements to improve the strength and improve human nature, sulfur, phosphorus content control in 0.030%, the main grades are U74, U71Mn.
2. The alloy rail is based on the carbon track, adding appropriate alloying elements such as V, Ti, CRr, Mo, etc., thereby enhancing the strength and toughness of the rail, China's alloy rail is RE-Nb rail, RE-Cr and V -Ti rail, the main grades are U76RENB, U75V, U76CrRE.
3. The whole length of heat treatment track is mainly above the two rails for the material through the heating and cooling control of the heat treatment process to improve its internal structure, refine the grain, the formation of pearlite structure, so that the rails to obtain high strength and high toughness.