HYDRAULIC SOLUTIONS

ABRASIVE WEAR & TEAR

This form of wear is extremely common and involves the scuffing or scoring of any lubricated surface. There are actually two forms of abrasive wear; two-body and three-body abrasion.

a. Two-Body Abrasion – This form of wear occurs when two lubricated surfaces come into direct contact. This is most likely the result of loss in terms of the lubricating oil film.

b. Three-Body Abrasion – This occurs when the clearance between two lubricated surfaces is filled by hard particles. When this occurs, it isn’t the other surface which causes the wear to the component in question, but rather the hard particles which score the surface and contribute to long term damage.

ADHESIVE DAMAGE

This is an extension of the common two-body abrasion. When the oil film between two lubricated surfaces moving relative to each other becomes lost or worn down, then the two surfaces will begin to scuff each other. This scuffing creates friction which, in turn, generates heat. If the friction and the heat are strong enough, then the two surfaces can often begin to stick together, or adhere.

Although complete adhesion and eventual seizure of the hydraulic system is completely possible in these situations, it is more common for one of the surfaces to tear microscopic high points away from the other.

FATIQUE WEAR

This form of wear and tear occurs in heavily-loaded, lubricated contacts, such as bearings and gears. Point loading can cause deformation of the component’s surface; this means that the resulting stress causes surfaces to crack and break apart.

CAVITATION WEAR

This typically occurs when oil-vapour bubbles, or even air bubbles, form at the inlet pipe for the pump. They then collapse under the pressure at the outlet. When they collapse, these bubbles form micro-jets which are powerful enough to erode even case-hardened steel.

EROSION DAMAGE

When the hydraulic fluid is contaminated with large amounts of silt-sized hard particles erosion is likely to occur. These particles are carried through the hydraulic system at a relatively high velocity and work on eroding the inside of the system.