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No matter it is 15kg light rail or 50kg heavy rail, they will have wear and damage after a period of time. It is generally believed that shear stress under the rail surface caused by contact stress is the main cause of rail damage caused by vertical force. Crane rail manufacturer YONGYANG will describe how damage to the rail surface occurs and how we can take means to avoid wear and tear.
Rail plastic deformation is proportional to the contact stress and inversely proportional to the rail hardness. When the contact stress is close to the shear yield limit of the rail, the contact surface begins to plastic deformation. When the contact stress reaches four times the shear yield limit, the contact surface occurs continuous cumulative plastic deformation, so that the rail head widening or rolling. At the same time the rail top surface metal hardening, hardness increases, the surface fatigue cracks, resulting in flake spalling. This is also the contact stress caused by surface fatigue wear.
When contact stress caused by contact shear stress is applied, the plastic flow deformation layer is deeper and the surface fatigue crack develops obliquely downward along the rheological direction. When the fatigue crack expansion rate is greater than the wear, the contact stress is larger inside the top of the rail to form a small circle, arc at the emergence of fish scale spalling crack, spalling crack depth corresponds to plastic deformation. Generally in the small radius curve outside diameter at up to 2mm or more. In bending the outer rail wheel track sticky creep, promote the development of cracks, the emergence of block before and after the fish scale cracks through. As the track is not flat, increasing the wheel/rail impact force, and crack development accelerated. Inclusions will accelerate the sprouting and development of cracks.
Generally speaking, the heavier the rail, the less damage to the rail and the less likely to bend and deform. According to this problem, there are two methods of strengthening.
1. Alloying of steel rails. Production process is simple, less investment, low energy consumption, the overall strengthening of the rail, uniform surface hardness, good weldability.
2. Heat treatment of carbon steel, this method can also improve the strength and hardness of the rail, while good toughness, saving alloy, suitable for mass production. Only the combination of micro-alloys and heat treatment, the two can complement each other to obtain higher strength, and the corresponding toughness, hardness and weldability of quality rails.
Both methods can significantly reduce the previous situation and the use of rails will be more convenient. However, despite all the precautions taken, nuclear damage to the new railroad cannot be absolutely avoided. In order to ensure the safety of traffic, must be regular rail flaw detection, timely elimination of hidden problems, to avoid major traffic accidents.
3, Reduce bending rail wear, the main measure is to improve the design of rolling stock bogie, improve the wheel-rail interaction conditions, reduce the friction between the wheel-rail. Also often check the rail, always take measures to find out the situation and eliminate hidden problems.
YONGYANG's products are widely used in railroad, seaport, mining industry and tunneling industry.etc. Light steel rail, heavy steel rail and mining support steel were awarded as well-known product by Hebei Provincial Administration of Quality and Technical Supervision, and the company is the designated production enterprises of mining support product for China coal industry companies, which occupy 70% of domestic market. We will keep on sharing things about railways, if you need to purchase them, please send us a message today to get the quote. We also have fasteners and beams for sale.
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