What Does Rolling Wear Mean?
Rolling wear is the material loss that occurs in a rolling contact between two surfaces in relative motion. The wear occurs when the two non-conforming solid bodies are in relative motion and their surface velocities at the contact area are identical in magnitude and direction.
Rolling wear between two surfaces may result in surface damage due to material loss from shear and fatigue fracture, preceded by mechanical deterioration, oxidation or corrosion.
Corrosionpedia Explains Rolling Wear
Rolling wear is not a wear mechanism; it is wear type of wear that occurs between rolling contacts and may result from various material removal mechanisms. Surface fatigue and adhesion are the most common; others include corrosion, abrasion and tribochemical action.
Rolling wear is among the wear types that occur in reciprocal rolling, unidirectional rolling and rolling with slip contact configurations. Free solid particles may also contribute to rolling wear when they attack the interacting surfaces. Rolling wear is influenced by:
- Material properties
- Operating environment
- Dynamics such as loads and rolling speeds
Corrosion rate is influenced by the distribution of forces, temperature distribution, mechanical wear, contact load, and the thickness and stability of the oxide film. The oxide film prevents direct metal-to-metal contact. The contact surfaces thus remain smooth by the oxide film and lower the wear rate.
A slip may occur between the driven and the braking roll, and lead to plastic deformation of the surface material. This makes the material more reactive in addition to allowing oxygen to penetrate into the grain boundaries, hence increasing surface corrosion and intergranular corrosion, which accelerates corrosive wear.
Surface damage such as loss of material and loss of protection occurs from the effects of rolling wear. Some methods used to reduce the effects of corrosion wear in rolling contacts include:
- Cathodic protection
- Choice of materials
- Use of hard and corrosion-resistant coatings
- Proper design
- Reduced temperature
- Speed and load
- Changing the operational environment