Sliding bearing the type of damage - bearing knowledge

1. Scratch ( Wear is in a 2) With the diameter of axle movement of hard particles in contact with the friction surface, it is on the surface of the particles and metal contact stress is low, they draw on bearing surface linear scars; Half embedded hard particles on the surface of the bearing shell can draw in the diameter of axle surface, linear scars are called scratch. Scratch wear is in a second, the direction of the linear scars and diameter of axle movement in the same direction. Lubricating oil film is broken, and will scratch on the surface of the diameter of axle wheel peak bearing shell, appear many linear scar, it is also wear is in a second. Hard particles embedded bearing surface and fall off, causing the dot scars of scrape. At the end of the particles of iron and sand. Scratch caused friction pair surface roughness, which reduces the carrying capacity of the lubricating oil film, and to form a new can scratch hard particles and on the surface of the friction wheel peak, causing a vicious cycle. 2. ( Three body) Abrasive wear into the bearing clearance of smaller particles, shifting between two friction surfaces, on the friction surface to produce extremely high contact stress, constitute the three body abrasive wear, similar to the grinding effect, make the bearing and the diameter of axle surface wear. Hard particles and high contact stress between friction surface friction surface of ductile metal to produce plastic deformation and fatigue damage, the friction surface of brittle metal embrittlement or peeling off. The abrasive wear scar is linear, the direction is consistent with the diameter of axle movement direction. When the edge contact, the lack of lubricating oil or oil membrane rupture, and so on and so forth will produce severe abrasive wear. Abrasive wear will lead to the diameter of axle and ( Or) Bearing shell geometric changes in size and shape, precision loss, bearing clearance, improves the performance of the sliding bearing a sharp deterioration in front of the life expectancy. 3. Stick bite ( Agglutination) Under the conditions of oil membrane rupture or lack of oil, the friction factor of the big lead to a lot of friction heat, bearing temperature rise. Under high temperature, a low melting point metal friction surface due to soften the adhesive on the friction surface, along with the diameter of axle rotation shearing action, adhesion of the surface of the metal from the original from, transferred to another friction surface, causing friction surface depressions and convex scars. This damage is adhesive wear. A bit sticky, friction increases sharply, bearing temperature rise further, a vicious cycle. When the adhesive is serious, diameter of axle rotational power can no longer be shear bonding point, will make the diameter of axle movement is terminated, commonly known as '' holding shaft, bearing damage completely. 4. Fatigue wear and fatigue wear and fatigue damage. Under cyclic load repeatedly function, in a direction perpendicular to the sliding direction, the friction surface fatigue crack, crack perpendicular to the bearing surface to the deep development, to combine with backing surface lining layer, transferred to runs parallel with the friction surface, the material from the friction surface is peeling off, pit shape damage. 5. If stripping manufacturing bearing shell, lining with backing binding force is insufficient or poor, in the process of bearing operation, under the action of load, local lining material will be stripped from the bush. Stripping and fatigue spalling some similar, but fatigue spalling pits around irregular, usually caused by poor combination stripping pit surrounding more smooth. 6. Corrosion of lubricating oil in use process continuously oxidation, oxidation often produce weak organic acid, it to the bearing material especially the lead corrosive cast copper lead, lead is characterized by a dot shedding, make the surface roughness. Strong inorganic acid to corrode steel shaft surface. Tin-based bearing alloy of tin is oxidized, in the form a layer on the surface of bearing bush of SnO2 and SnO black hard cover, hardness in the range of 200 ~ 600 hs. The cover is extremely harmful for bearing, it is very hard, can scrape shaft neck surface, and makes the bearing clearance smaller. 7. Erosion ( 1) Cavitation cavitation is contact with the liquid and solid surface generated by the relative motion form of surface damage. When the lubricating oil in the oil film of low pressure area, oil will form bubbles, the bubbles movement to high, the pressure under the action of air bubble breaking, the breaking of instant impact and high temperature, solid surface under the effect of the impact of repeated, material fatigue peeling, the friction surface appear small pits, and then developed into the cavernous scars. Overload, high speed, and the sliding bearing with higher load and speed, the cavitation often occur. ( 2) Fluid erosion fluid fierce shock can cause fluid solid surface erosion, point to appear on the solid surface scars, the damage of a smooth surface. ( 3) Electrical erosion due to the motor or electric leakage, produce electric spark between the friction surface, on the friction surface caused by dot scar, is characterized by damage to and fro in a hard shaft neck surface. 8. Fretting wear and tear in the lining and backing, the combination of the bearing and the bearing surface, due to the micro vibration between the metal surface ( Slip) And oxidation combined, form the adhesive wear, oxidation ( Corrosion) Wear and abrasive wear in the form of 3 kinds of compound wear, called micro wear, it will cause the dot scars on the surface of the combination.