Types of Wear – Classification and Prevention
Wear is one of the biggest challenges for engineers trying to build durable workpieces. Besides fatigue, wear is one of the main factors limiting the durability of metals such as steel. Wear is the loss of mass of a material surface due to abrasive, rolling, impact, scratching, chemical and thermal stresses. Wear is also part of tribology.
However, there are different types of wear. The most common in steels and other metals are abrasion, adhesion and corrosion. Each type of wear has its own difficulties and disadvantages, which can be influenced by the materials, the lubrication properties and the surface of the material.
What are the damages of wear?
Wear damages the engineering component in two ways. Firstly, the component reduces its dimensions due to the loss of materials from the contacting workpieces. The resulting greater distance between the moving parts leads to a plethora of problems such as high vibrations and noise levels, reduced efficiency and system disturbances. Under dynamic loading, the reduced component size can lead to fatigue fractures and eventually to a catastrophic failure.
Moreover, material detaches from the worn surface. This so-called wear debris can lead to contamination and is therefore similarly harmful. Further, it can promote the development of more wear by acting as an abrasive when trapped between the contact surface. The accumulation of debris in a pipeline or an oil filter can lead to a limited functioning of a system. The resulting costs are enormous. Thus, great efforts have been made to reduce or eliminate wear since the early days of industry.
The different types of wear
While abrasion, adhesion and corrosion are the most common types, there are several other types of wear.
- Abrasive Wear: This is the most common type of wear, and it occurs when hard particles or rough surfaces slide across a softer surface, leading to material removal. It can be further divided into two subtypes: two-body wear and three-body wear. In two-body abrasive wear, the hard surface of one material directly causes abrasion on the other. In three-body abrasive wear, free particles trapped between two surfaces cause abrasion.
- Adhesive Wear: Also known as galling or scuffing, adhesive wear happens when two metal surfaces slide against each other without sufficient lubrication. This can cause ‘welding’ at the contact points and, as sliding continues, these miniature welds break off, leading to material transfer from one surface to another. This type of wear is common in sliding and rolling applications.
- Fatigue Wear: This type of wear is also called surface fatigue and occurs when a material is subjected to repeated stress or strain, causing cracks that can lead to material loss. It’s common in components that experience cyclic loading, such as gears and bearings. Over time, the repeated stress can cause cracks to form beneath the surface, which can then propagate to the surface and cause fragments of material to detach.
- Erosive Wear: This happens when particles in a fluid medium impact a surface at high velocity, causing material removal. It’s often seen in hydraulic machinery or pipes carrying abrasive fluids. The severity of erosive wear depends on factors such as the velocity and size of the particles, the angle of impact, and the hardness of the surface.
- Corrosive Wear: This type of wear occurs when a material’s surface is chemically attacked by its environment. This can lead to the formation of pits and cracks, which can then accelerate mechanical wear. Corrosive wear is common in materials exposed to harsh environments, such as those containing acids or salts.
- Fretting Wear: This type of wear occurs when two surfaces are in contact and subjected to small, oscillatory relative motions. This can cause the removal of material and the formation of wear debris, which can then accelerate further wear. Fretting wear is a common problem in bolted connections and bearings.
How to prevent wear?
Preventing wear is crucial in many industries to ensure the longevity and efficiency of machinery and equipment. There are several strategies that can be employed to mitigate wear. Material selection is a primary consideration; choosing materials with high hardness can help resist abrasive and adhesive wear. Surface treatments, such as coating or hardening, can also enhance a material’s resistance to wear. Proper lubrication is another key factor in preventing adhesive wear, as it reduces the direct contact between surfaces. Regular maintenance and inspection can help detect early signs of wear and prevent further damage. In terms of design, ensuring that components are properly aligned and that loads are evenly distributed can help prevent fatigue wear. Finally, in environments where corrosive wear is a concern, using materials that are resistant to chemical attack or employing protective barriers can help prevent wear.
Elevate Your Wear Prevention Strategies with Bortec Group Services
Understanding and mitigating wear is crucial for the longevity and efficiency of your engineering components. If you’re looking to take your wear prevention strategies to the next level, BorTec Group offers specialized services that can significantly enhance the durability and performance of your materials:
- Boronizing: This process offers high hardness and exceptional protection against abrasive and adhesive wear. It’s particularly useful in industries like valve construction, power plant technology, and gear and transmission technology.
- Hardening of Stainless Steel: Utilize the patented BORINOX® process to achieve up to 5 times higher hardness and high wear protection. This treatment is suitable for a wide range of stainless steels, including austenitic, duplex, and martensitic steels.
- Nitriding: Opt for an environmentally friendly gas-based diffusion process that results in a very hard and wear-resistant edge zone. This process is effective in protecting against abrasion, cavitation, and fatigue.
Don’t let wear compromise the integrity and efficiency of your components.Contact us today for a consultation and elevate your wear prevention strategies!
