Hardness testing – some information for non-specialists

Note: for a more comprehensive explanation of the concept, origins and application of hardness testing, see our major article here.

The term ‘hardness’ is used to describe a material’s ability to resist being deformed. Hardness testing provides data on how hard materials are by giving the tested materials a number which technicians can use to decide if a particular material is suitable for a particular application. In many industrial applications this is extremely important (see below).

Brinell hardness testing – the basics

The Brinell hardness test is employed to determine the hardness of metals. It tends to be used in harsh industrial shop-floor environments such as foundries, forges and steelworks because it can be used on coarse-grained, roughly prepared surfaces.

In the Brinell test a tungsten carbide ball indenter is forced into the surface of the metal in a tightly controlled manner. The diameter of the indentation produced by the ball is then measured in a minimum of two axes, normally with a purpose-built microscope, and the diameter is then fed into an equation to give a hardness rating. Follow this link to read a much more detailed explanation of Brinell hardness testing.

Why hardness testing is important

Whether it be for aerospace, automotive, oil and gas or rail (among others), hardness testing machines are an essential investment for many companies because of the safety-critical nature of their products. The worst railway crash in Germany’s history was caused by a wheel being too brittle, and since that crash, in 1998, the manufacturer of the wheel has purchased several of our highest specification machines.

As an example, if you consider the pulleys that a lift cable goes around, overly hard ones would wear out the cable and excessively soft ones would be worn out by the cable. In either case, you’d prefer not to be in a lift at the point it became obvious that the materials were incorrect! Or consider a more ‘heavy duty’ example: every tank track link in use by the British Army since approximately 1982 has been tested by a Foundrax machine, testament to the accuracy, high quality and reliability of our products.

How to choose a hardness testing Machine

There are several factors to consider, including the rate of testing you wish to achieve, the burden on the operators, the degree of automation, and the size of the components being tested (for small industrial components the Rockwell test is preferred) – not to mention health and safety (it is not unknown for people to test longer items by holding one end in the testing machine and the other on a crane – without considering that not only may the results be incorrect as a result of movement under load, but if the machine should be pulled over by the component, the operator could easily be seriously injured).

Our hardness testing machines are suitable for every normal industrial application and are designed to give years of trouble-free service in
harsh industrial conditions. All are manufactured to meet the appropriate ISO and ASTM standards. Follow this link for detailed information about our Brinell hardness testing machines.

Special hardness testing machines

Certain circumstances require a unique solution. If you have a Brinell hardness testing requirement which is highly unusual we can design you a test machine ‘from the ground up’ – which is why we offer special-purpose hardness testing machines following detailed consultation with the customer. Every machine we supply is designed and manufactured in the UK.

If you need to know more about why hardness testing is so important, don’t hesitate to get in touch with the Foundrax experts on 01458 274888 today.

Alex Austin

Alex is a member of the ISE/101/05 Indentation Hardness Testing Committee at the British Standards Institution. He has been part of the delegation to the International Standards Organisation advising on the development of the standard ISO 6506 Metallic materials - Brinell hardness test and is the chairman and convenor for the current ISO revision of the standard.

Alex’s industrial pedigree can be traced back to 18th Century Bohemia, where his forebears ran a foundry supplies business and in his work at the British Standards Institution he has used his extensive knowledge of Brinell testing in the UK’s steel, oil and gas industries to ensure that the interests of the end user are appropriately represented.
Alex has been Managing Director of Foundrax Engineering Products since 2001. A skilled negotiator and commercial manager, Alex leads a team of engineers and technicians with skills ranging all the way from traditional toolmaking to embedded software systems, and he is currently engaged in bringing the next generation of Brinell hardness testers into production (the first of these was launched in 2021). He recently expanded the production team and purchased a new factory space to cope with increasing orders, particularly for Foundrax’s custom-designed, custom-built, bridge-type hardness testing machines.