Main types of mechanical wear and solutions

Thread Content

Many mechanical devices operate in harsh environments, and as a result of these conditions, the wear of their components accelerates. There are various ways in which components can fail, with failure due to wear, deformation, fracture, corrosion, and creep being the most common causes. 　Wear is the main cause of component failure; statistics show that 75% of mechanical components fail due to wear. In most mechanical devices, mechanical wear is more pronounced due to factors such as heavy loads, high impacts, high temperatures, and harsh working conditions. 　Based on the causes of mechanical wear and the nature of the wear process, wear can be further classified into adhesive wear, abrasive wear, fatigue wear, and corrosion wear. 　(1) Adhesive wear: Microscopically, the surfaces of mining machinery parts are uneven; when two such surfaces come into contact, it is actually a local point contact. Under relative sliding and a certain load, plastic deformation or shear occurs at the contact points, causing the surface temperature of the parts to rise; the surface film breaks down, and in severe cases, the surface metal softens or melts. At this point, adhesion occurs at the contact surface, and due to relative motion, the old contact points are continuously severed. New teachings have formed again. Such a cycle leads to gradual wear. 　 (2) Abrasive wear: The phenomenon in which hard particles or protrusions cause material to break off during friction is known as abrasive wear. According to foreign statistics, in the metallurgical mining machinery industry, losses caused by abrasive wear account for approximately 40% of the total costs ； It accounts for 30% of the costs in the coal industry. Therefore, the proportion of part failures caused by abrasive wear is relatively high. 　(3) Surface fatigue wear: Fatigue wear occurs when friction is present on a mechanical surface, along with alternating contact stresses that cause initial microcracks to form on the surface; these cracks then continue to develop, leading to the detachment of material particles. For example, on the surface of rolling elements in rolling bearings, near the pitch circles of gear teeth, and on the contact surfaces between rails and wheels, small pitting or pockmark-like depressions often appear; this is typical of surface fatigue wear. 　　The main difference between fatigue wear and part fatigue failure is that fatigue wear involves friction and wear, plastic deformation and heating of the surface, and is influenced by a liquid lubricant. The latter is mainly subject to fatigue failure caused by alternating stress. (4) Corrosive wear: When two surfaces rub against each other in a corrosive environment (gas or liquid), reaction products are formed on the mechanical surfaces. These reaction products have a weak binding force to the surface, and they are generally worn away through continuous friction. Once the metal is exposed as a result of this wear, new reaction products are quickly formed, and this cycle repeats itself, resulting in corrosive wear. Its fundamental difference from ordinary chemical corrosion is that the latter involves no friction. To address the issue of mechanical wear, it is necessary to reduce the contact and friction between mechanical components as well as between those components and other particles, and to minimize exposure of the machinery to corrosive environments. Currently, new wear-resistant and corrosion-resistant materials, such as spray-applied polyurethane elastomer materials, offer an excellent solution for improving the wear resistance of machinery. Spray-type polyurethane elastomers are easy to apply; they can be sprayed onto the surfaces of virtually any material in complex shapes at room temperature. They can be formed in a single application without any sagging, and they are environmentally friendly as they contain no volatile organic compounds. Their setting time is short – walking strength is achieved within just a few dozen minutes. When submerged, their wear resistance is 8 times that of cemented carbide steel, 7 times that of vulcanized rubber, and 3 times that of ultra-high molecular weight polyethylene. They can withstand erosion from acids, alkalis, oils, water, and other substances with a pH range of 3–11, offering excellent corrosion resistance. At the same time, it features high resistance to salt spray corrosion and freezing, excellent adhesion, attractive appearance; products can be colored in various shades as desired, and it also has very good UV protection properties.