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1. What is wear or abrasion of steel?

Wear is loss of material from a surface subject to mechanical contact. Abrasion is a kind of wear arising from particles or sharp edges penetrating a surface.

2. What are the different types of wear of steel?

Wear of steel can be described as three main categories; adhesion, abrasive wear and surface fatigue. Adhesion is when two bonding surfaces are pressed together and subjected to a relative motion. Abrasive wear is particles or abrasive material with either sliding, erosion or impact wear or a combination of these. Surface fatigue is a specific wear of components with high surface pressure levels, e.g. rails and bearings.

3. What influences wear of steel?

The hardness of the steel and of the abrasive have the biggest influence. Particle size, sharpness, velocity and impact angle also affect the wear processes. Temperature and corrosive agents should also be mentioned.

4. How is the wear of steel measured?

Large equipment such as mining truck bodies, buckets or linings are normally inspected by using an ultrasonic thickness gauge measuring thickness reduction. Mines use the ultrasonic gauge to regularly inspect the whole fleet of machinery. Hammers in crushers are typically assessed by measuring with a ruler but usually hammers need to be replaced once production output reaches the lower limit. In laboratory wear testing, the most common is to measure the weight loss of the samples.

5. What is the difference in lifetime between wear steel grades?

With all other conditions kept constant, increased steel hardness will extend the lifetime of a component subject to wear. The relation between hardness and lifetime is far from linear, in particular since a change in wear mechanism often occurs when the steel hardness is changed. Hardox® WearCalc can be used to estimate the relative lifetime and wear resistance. 

6. What causes wear of steel?

Wear of steel is a damage process due to mechanical contacts. It can start with a hard enough particle with sharp edges coming into contact with the steel surface, moving relative to the steel and creating a scratch. A scratch is surface damage where a small amount of steel, a chip, is removed or lost. When repeated many times, this process is called wear. 

7. How can wear of steel be avoided?

An efficient way to reduce wear of steel is to upgrade to a harder, more wear-resistant steel. In addition, it is often possible to make design changes to protect the steel, for example with a so-called dead bed, to change the material flow, or to reduce the contact pressure. 

8. What is abrasive material?

Abrasive material can include ore, overburden, waste rock and aggregate as well as recycled materials like glass or different kinds of scrap metal to mention just a few. The abrasiveness comes from sharp edges hard enough to cause surface damage when moving and in contact with another material surface.

9. Is a harder steel grade always more resistant to wear?

Yes, a harder steel grade will always have greater wear resistance. 

10. What is the difference between Brinell, HB, HBW, HLD, HRC, HV, Leeb, Rockwell and Vickers?

These are hardness measurement methods all using a tip that is pressed into the test piece with a specified force and leaving a dent, the size or depth of which is measured and used to calculate a hardness value. The indenting tip geometry and the force used are specific to each method. There are no official conversion tables between the different methods.

11. How does high temperature affect the wear of steel?

Increasing temperature will make any steel softer and less wear resistant. The degree of softening varies a lot for different steel types. Higher temperature will also increase the oxidation of the steel surface and this will also affect the wear rate when the oxidation layer is worn off and an indentation builds up again.

13. What is a wear test for steel?

There are laboratory tests and tests in real service. A laboratory test is normally a simplified version of reality. This helps in the understanding of mechanisms but lacks full predictability. Real service tests and measurements enable fair predictability, e.g. when used in combination with Hardox® WearCalc

14. Is chromium carbide steel better than wear steel?

Chromium carbide is a wear-resistant material that utilizes hard carbides in a softer matrix. In some situations, a chromium carbide material can perform better than a wear steel, for example, a smaller size of abrasive material and sliding wear. The risk with chromium carbide material is that high impact energies or contact pressures could chip or even delaminate the hard surface.

15. Is manganese steel better than wear steel?

Manganese steel is a material that work hardens and gets much harder when subject to impacts. There are substantial workshop challenges with manganese steel. Wear plate, type Hardox®, is more versatile and workshop friendly.

16. Is stainless steel better than wear steel?

In general, stainless steels have lower hardness than wear steel and so lower wear resistance. However, performance can be very good in a high-corrosive environment with limited or no wear.

17. How can lifetime be estimated compared to wear of steel?

Estimates are tricky due to the number of variables in real service and our limited knowledge. Using measured data in a relative model where e.g. wear steel hardness can be varied has been successful. Hardox® WearCalc is recommended for this purpose.

18. How can the wear of steel be calculated?

Regular measurements of lost weight, reduced thickness, etc. in real service enable extrapolation to determine lifetime. Hardox® WearCalc can be used to successfully estimate  lifetime when changing to wear plate with a different hardness. 

19. What is WearCalc?

Regular measurements using an ultrasonic thickness gauge based on loads or hours is the most common way to plan maintenance and detect the wear rate. To estimate wear, SSAB have developed the calculating tool Hardox® WearCalc. 

20. What is a structural wear steel?

A structural wear steel is hard (strong) enough to be considered a wear steel and has properties similar to structural steels. 

The information in this report is only applicable to SSAB’s products and should not be applied to any other products than original SSAB products. 

This report provides general results and recommendations for SSAB steel products. This report is subject to SSAB’s Terms of Use. It shall be the user's responsibility to verify that the information contained herein is correct and is suitable to be used for the particular purpose and application of the user. The report is intended to be used by professional users only who possess adequate expertise, qualification and knowledge for the safe and correct use of the results and recommendations in this report. This report is provided “as is”. The use of the report is at user’s own discretion and risk and that users will be solely responsible for any use of this report. SSAB disclaims any liability for the content or potential errors of this report, including but not limited to warranties and condition of merchantability or fitness for a particular purpose or suitability for individual applications. SSAB shall not be liable for any kind of direct or indirect damages and/or costs related to or arising therefrom, whether special, incidental, consequential or directly or indirectly related to the use of, or the inability to use, the report or the content, information or results included therein.