Fretting corrosion amplitude

Fretting corrosion is a combined wear and corrosion process in which material is removed from contacting surfaces when motion between the surfaces is restricted to very small amplitude oscillations (often, the relative movement is barely discernible ranging from a few tens of nanometers to a few tens of micrometers). Fretting occurs where low-amplitude oscillatory motion in the tangential direction takes place between contacting surfaces, which are nominally at rest. (Waterhouse) It is necessary that the load be sufficient to produce a distortion of surfaces. This is a common occurrence, since most machinery is subjected to vibration, both in transit and in operation. Figure 6.41 shows a typical example. Pressed-on wheels can often fret at the shaft/wheel hole interface.31... 

One definition of fretting is "Wear phenomena occurring between two contacting surfaces having oscillatory relative motion of small amplitude." Note Fretting is a term frequently used to include fretting corrosion. This usage is not recommended. 

Another is the Small amplitude oscillatory motion, usually tangential, between two solid surfaces in contact." Note Here the term fretting refers only to the nature of the motion without reference to wear, corrosion or other damage that may follow. The term fretting is often used to denote fretting corrosion and other forms of fretting wear. 

Fretting is a phenomenon of wear which occurs between two mating surfaces subjected to cyclic relative motion of extremely small amplitude of vibrations. Fretting appears as pits or grooves surrounded by corrosion products. The deterioration of material by the conjoint action of fretting and corrosion is called Fretting Corrosion. Fretting is usually accompanied by... 

A type of wear that occurs between tight-fitting surfaces subjected to cyclic relative motion of extremely small amplitude. Usually, fretting is accompanied by corrosion, especially of the very fine wear debris. Fretting refers to metal deterioration caused by repetitive slip at the interface between two surfaces. When metal loss is increased by corrosion, the term fretting corrosion should be used. 

Park Y. W., Sankara Narayanan T. S. N. and Lee K. Y. (2006a), Effect of fretting amplitude and frequency on the fretting corrosion behaviour of tin plated contacts . Surf. Coat. TechnoL, 201,2181-92. (doi 10.1016/j.surfcoat.2006.03.031)... 

Fretting corrosion occurs at the interface between two closely fitting components when they are subjected to repeated slight relative motion. The relative motion may vary from less than a nanometer to several micrometers in amplitude. Vulnerable objects are fits, bolted joints and other assemblies where the interface is under load. ... 

The fretting wear rate is directly proportional to the normal load for a given slip amplitude. However, in the total-slip situation, the frequency has little effect. (Water-house)88 In a partial-slip situation, the frequency of oscillation has little effect on wear rate per unit distance in the low-frequency range, whereas the increase in the strain rate at high frequencies leads to increased fatigue damage and increased corrosion due to a rise in temperature.75... 

Fretting is of course not a form of corrosion, but it is often confused with corrosion, and can sometimes be associated with serious corrosion. It is in fact a form of oxidative wear which occurs when solid surfaces, usually metallic, rub together in a low-amplitude oscillation. The damage can be very severe. With metals it is characterized by pitting which resembles corrosion, and with ferrous metals there is a characteristic production of red ferric oxide. 

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