Wear resistance is one of the key characteristics that are controlled by alloying and heat treatments in metals. Alongside strength, toughness and ductility, being able to control the wear resistance of a material allows increased efficiency and longevity in industrial applications.

What is Wear Resistance

Wear is the gradual removal of material from a surface or part by either physical abrasion or chemical action. Wear resistance is generally measured by measuring relative material loss in an abrasion test.

Abrasion-resistant steel is used in applications where conventional high-strength steel is not sufficiently resistant to wear; it can last up to 4 times longer in such applications.

Hardness is the ability to withstand rubbing or scraping, whereas toughness is resilience against fracturing. Certain non-metals do not follow this pattern and are used for abrasion resistance, such as rubber.

What are the Types of Wear Resistance?

Wear can be caused by a solid surface, small solid particles, or a fluid suspending solid particles.

Adhesive Wear

Adhesive wear is caused by the contacting of microscopic high points on the surface of the two wearing materials This creates spots of micro welding, where peaks on the surface of one material are ripped away and deposited on the other.

Adhesive wear causes increased surface roughness, further increasing the rate of future wear. Wear-through this process is commonly termed as ‘Galling’ and is often seen on stainless to stainless fasteners.

Abrasive Wear or Erosion

Caused by hard particles impacting or abrading a surface, abrasive wear is most often associated with small particles suspended in water or other liquid. It can also be used to define grinding wear between two surfaces.

On a microscopic scale, abrasive wear is caused by a cutting or plowing action. The process can be sped up by a third body abrasive material, harder than the material(s) wearing away.

Corrosive Wear

Corrosive wear is a chemical form of wear, where no physical contact or motion needs be involved. Corrosive wear can affect many materials, provided there is a corrosive substance present. For steel, this can be water or humid air, for ALUMINIUM, various acids quickly erode the oxide layer.

Various paint and coating systems are used to protect against corrosive wear, such as powder coating, anodizing, or galvanizing.

Surface Fatigue

In materials science, fatigue is the weakening of a material from cyclical loading. Surface Fatigue is a form of wear caused by a repeated loading of a surface, causing embrittlement and localized structural damage.

Both hardness and toughness affect the rate at which a material experiences surface fatigue. Thus ALUMINIUM and other soft materials are more susceptible than cast iron or steel.

Why do Some Materials Resist Wear?

Different materials resist wear at different rates, which are also heavily affected by the type of wear, e.g. abrasion or corrosive wear.

Mechanical Properties

Typically in metals, the biggest factors to wear resistance are Hardness, Toughness and Lubricity. If two materials are in contact with each other, the harder one will always wear less than the softer one.

Lubricity is a unique property that is not often discussed outside the realm of wear resistance and machining. Some materials have a natural action of reducing wear by being self-lubricating. Common examples include certain bronze alloys as well as gray cast iron.

Chemical Properties

The best resistance to corrosive wear is the inherent protection from the material composition, the best example being using a material resistant to corrosion in a marine environment. Steel would quickly be worn due to the cycling of rust and corrosion, stainless steel however would be unaffected.

Metals With Good Wear Resistance

As discussed, for avoiding corrosive wear, stainless steel can be a great choice, there are however some environments where stainless will corrode and therefore wear, such as sulphuric or hydrochloric environments.

Alloying elements such as chromium and nickel form an oxide layer on the surface, resisting the chemical attack.

For resisting abrasion wear, materials such as high-carbon steel or cast iron are often used. Adhesive wear is best avoided using materials with a high lubricity, such as phosphor bronze.

Buy Wear Resistant Materials at Metals Supermarkets Online

Available across the nation, Metals Supermarkets branches stock many of the metals discussed in this article, including cut-to-size bronze, stainless steel and more. For high performing abrasion resistant high-carbon steels, we stock a wide range, including AR200 / AR400 / AR450 and AR500

To find your local Metals Supermarkets store, use our online store locator.