Common Characteristics

The common characteristics of fretting and Fretting wear and wear Share many common characteristics but, at the same time, are distinctly different in several ways. Basically, fretting action has, for many years, been defined as a combined mechanical and chemical action in which contacting surfaces of two solid bodies are pressed together by a normal force and are caused to execute oscillatory sliding relative motion, wherein the magnitude of the normal force is great enough and the amplitude of the oscillatory sliding motion is small enough to significantly restrict the flow of fretting debris away from the originating site. More recent definitions of fretting action have been broadened to include cases in which contacting surfaces periodically separate and then reengage as well as cases in which the fluctuating friction-induced surface tractions produces stress fields that may ultimately result in failure. The complexities of fretting action have been discussed by numerous investigators-who have postulated the combination of many mechanical, chemical, thermal, and other phenomena that interact to produce fretting. Among the phenomena postulated are plastic deformation caused by surface asperities plowing through each other, tearing and welding of contacting asperities, rupture and shear of asperities, friction-generated subsurface shearing stresses, dislodging of particles and corrosion products at the surfaces, chemical reactions, debris accumulation and alginato, abrasive action, micro crack initiation, and surface delimitation. Damage to machine parts due to fretting action may be manifested as corrosive surface damage due to fretting corrosion, loss of proper fit or change in dimensions due to fretting wear, or accelerated fatigue failure due to fretting fatigue. Typical sites of fretting damage include interfere.nca fits; bolted, keyed, splined, and riveted joints; points of contact between wires in wire ropes and flexible shafts; friction clamps; small-amplitude-of-oscillation bearings of all kinds * contacting surfaces between the leaves of leaf springs; and all other places where the conditions of Fretting persist. Thus, the efficiency and reliability of the design and operation of a wide range of mechanical systems are related to the fretting phenomenon.

May wear be defined as the undesired cumulative change in dimensions caused by the gradual removal of discrete particles from contacting surfaces in motion, due predominantly to mechanical action. It should be further recognized that corrosion often interacts with the wear process to change the character of the surfaces of wear particles through reaction with the environment. Wear is, in fact, not a single process but a number of different processes that may take place by themselves or in combination. It is generally accepted that there are at least five major subcategories(en) of wear, including wear, abrasive wear, corrosive wear, surface adhesive fatigue wear and deformation wear. In addition, the categories of fretting wear and impact wear have been recognized by wear specialists. Erosion and cavitation are sometimes considered to be categories of wear as well. Each of these types of wear proceeds by a distinctly different physical process and must be separately considered, although the various subcategories(en) may combine their influence either by shifting from one mode to another during different eras in the operational lifetime of a machine or by simultaneous activity of two or more different wear modes. We provide Professional technology, excellent product quality and intimate after-sales service when you purchase Primary jaw crusher, Vibrating screen, from our company.As a professional mining machinery exporter, we will win your trust with our delivery speed, Enterprises Credit and product quality.

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