How can a metal or part have uneven hardness?

Hardness Testing

The hardness of a metal is important for many reasons. For example, it is this property that affects the metal’s ability to resist deformation. It also has an impact on the resistance to abrasion and can affect the ability to cut it. It is important to get hardness testing as part of the quality checks. This can ensure there are no uneven patterns or flaws.

Why does unevenness happen?

Manufacturers use different types of heat treatment to improve the hardness of metals. The unevenness can occur because of issues with the heating. If it is uneven, there can be points where it does not get as deep into the metal. Where it is shallower, the metal won’t be as hard.

The heat cycle itself must also be optimised to make sure it is right for the part. If it is too short, the pattern will be too shallow. On the other hand, if it is too long, it can cause problems like decarbing in steel. If that happens, you can have big variations in the hardness pattern.

The unevenness can also occur as a result of issues with the quenching. When the manufacturer quenches a metal, they should try to get it as even as possible so it hits all parts of the metal simultaneously. On top of that, they need to control the direction of the quench.

Even when the heating and quenching is correct, there can still be slight differences in the hardness. This can happen purely because of the shape of the product. For example there may be sections that protrude further than others. As a result they will heat up much faster than other points. It can make them harder.

Arranging hardness testing

Format NDT Ltd is a team you can rely on for checking the hardness of various metals. We use a range of methods to get the most accurate results, including RH, BH, and VH. The equipment we use is completely portable so we can visit your site to test everything. That reduces disruption and provides more value for money.

So, if you need reliable hardness testing from one of the UK’s top experts, speak to us. We support businesses in many industries, helping them to ensure their metals meet the right quality specifications.