What causes fretting?
Fretting is caused by adhesion of contact surface asperities, which are subsequently broken again by the small movement. This breaking causes wear debris to be formed. If the debris and/or surface subsequently undergo chemical reaction, i.e., mainly oxidation, the mechanism is termed fretting corrosion.
What is connector fretting?
Fretting corrosion is one of the leading causes of connector failure and yet many still remain unaware of what it is or how it can be prevented. Fretting corrosion is the result of micromotion caused by vibration and/or thermal expansion due to heating or cooling cycles.
What is fretting damage?
Fretting corrosion refers to corrosion damage at the asperities of contact surfaces. This damage is induced under load and in the presence of repeated relative surface motion, as induced for example by vibration.
What causes terminal fretting?
Fretting is a known condition, where oxidation of terminal connections due to abrasion from thermal cycling, vibration etc, can lead to a loss of connection. Cycling a connector with terminals that exhibit symptoms of fretting often tends to result in a temporary fix, as became the situation on this car.
How do you stop fretting?
Means of preventing fretting corrosion :
- lubrication with oils or greases, to reduce friction and exclude oxygen from the interface.
- Increase in the hardness of one or both materials in contact.
- Use of seals to absorb vibrations and exclude oxygen and/or moisture.
What is meant by fretting and the causes and consequences?
Fretting is wear that occurs as two or more materials are repeatedly moved against one another under a load. Vibration is one of the most common causes of fretting. Fretting causes the surface of one or more of the materials involved to be degraded. This degradation often consists of grooves and pits.
What does fretting corrosion look like?
5.12 Fretting corrosion It appears as pits or grooves surrounded by corrosion products. Fretting corrosion may also be known as friction oxidation, wear oxidation, chafing, or false Brinelling (because of the appearance of pits similar to the indentations created in a Brinell hardness test).
How is fretting corrosion treated?
Other methods to control fretting corrosion include use of hard materials that resist wear, use of a gasket that absorbs vibration, increasing the load (which will decrease relative motion) and increasing roughness and so increasing friction between the materials (increasing the friction decreases the relative motion …
What are the signs of fretting corrosion on steel?
Under the effect of cyclic stress, small gaps appear between the surfaces in contact. The result is either a loss of material or the initiation of cracks. Contact corrosion, which is a side effect of fretting corrosion, almost always results in a blockage since the lack of functional movement prevents debris removal.
What are the factors that affect the rate of fretting?
Mechanical factors affecting the fretting properties include coefficient of friction, pressing force, and amount of relative slip. In fretting fatigue, cyclic stress, which is the sum of cyclic applied stress and cyclic friction stress caused by fretting, is applied to the material.