The phenomenon of loss of metal in the relative movement of parts is known as the wear of parts. The occurrence of wear will cause changes in the shape, size and surface properties of the parts, which will gradually reduce the working performance of the parts.Wear is sometimes beneficial, such as running-in. According to different friction principles, wear can be divided into abrasive wear, adhesive wear,fatigue wear and corrosion wear.
The abrasive wear caused by the hard particles between the friction surfaces is called abrasive wear.The hard particles, called abrasives, come mainly from dust in the air,impurities in lubricating oils, and metal particles that fall off the surface of parts during movement.
Abrasive wear forms:fatigue peeling or plastic extrusion: abrasive sandwich between two friction surfaces, will produce a concentrated high stress on the metal surface, so that the surface of parts fatigue and peeling (such as abrasive into the tooth surface, often fatigue and peeling). For plastic materials, plastic extrusion will occur on the surface (such as abrasive into the bearing is prone to plastic extrusion)
Scratch: Abrasives mixed in gases and liquids that wash the working surface of a part at a certain speed with the fluid and produce scratches (e.g. needle valve couplings in diesel injectors).
The morphological factors of abrasive wear: the distance and speed of the abrasive passing between the friction surfaces; the interaction force between the abrasive and the metal surface; part hardness; abrasive hardness; the size of abrasive particles.
Measures to reduce abrasive wear: the abrasive wear of automobile engine is mainly caused by the abrasive in the air, the abrasive in the air is mainly dust and sand, therefore: to have a good filtering effect of air filters, fuel filters, the filtering effect of diesel oil requires more stringent; lubricant filters, often cleaning oil filters increase; The wear resistance of the parts is improved by increasing the surface hardness of the parts and making the surface hardness as high as possible than the abrasive hardness, so as to improve the wear resistance of the parts.