Abrasion

Abrasive wear accounts for 60% of all wear.  Abrasion is the scratching or grinding of hard particles into a softer surface.  Two forms of abrasion will be described here-low stress, sliding abrasion and high stress, grinding abrasion.  Typical applications include:

Agricultural implements Conveyor screws
Augers
Road rippers

Bulldozer blades
Fan blades
Paving screws
Coal feeder screws

Cement chutes
Pug mill paddles
Coal chutes
Pulverizers

Low Stress Scratching Abrasion:

This is the least severe form of abrasion since the abrasive particles do not fracture and are usually small and not constrained.  The small particles slide freely over the metal surface, scouring the surface as they move across it at varying velocities.  An example is dry sand flowing over a part such as, agricultural implements, classifiers, or chutes.  Since there is no impact associated with this type of wear, high hardness carbide containing alloys, such as high carbon/high chromium carbide, complex carbide, tungsten and vanadium carbide are best for this type of abrasion.

Scratching Abrasion

Grinding Abrasion

Grinding abrasion occurs when abrasive particles are ground between two surfaces under pressure, causing the abrasive particles to fracture and be crushed.  The significance of the fracturing of the abrasive particles is that fresh, sharp cutting edges are continually being generated.  This increases wear rates by comparison with rounded abrasives.  Grinding abrasion is different from gouging abrasion by the particle size.  Although the line is not perfect, particles over 2" (50mm) would cause gouging, while smaller particles would most likely fall into the classification of grinding abrasion.  Alloys to resist abrasion must be both hard and tough.  Suggestions include chromium carbide and complex carbide.

Typical components subjected to high stress grinding abrasion are pulverizers, ball mills, road rippers, augers, agricultural implements cutting through hard soil, muller tires, and rollers on dirty track.

Abrasion Resistant Products