A nickel alloy immune to chloride stress corrosion cracking

Corrosion is a big issue in most industries, from construction to power. It is an even bigger concern when the conditions encourage it. For example there may be a lot of moisture, high temperatures, the presence of oxygen, and corrosive elements like chlorides. Luckily you can take steps to address the concern. One of them is to choose the right materials. Nickel alloy round bar, especially alloy C276 is a great option if you want high resistance.

What is CSCC?

One type you may need to take into account is chloride stress corrosion cracking. It is a particular concern in industries like power and nuclear. What happens is chlorides attack certain metals along the grain boundary. If the item is under tensile stress, it can cause surface cracks that look like spider webs. With enough time they can make the metal so brittle it will break off in the hand.

What causes it?

CSCC can occur when the right conditions persist. Firstly, there must be chlorides and oxygen. Plus, heat is necessary and there must be a sufficient amount of time for the corrosion to occur. Finally, for this type of cracking, there must be tensile stress on the product. That is why it is common on pipelines that have high pressure, high temperatures, and high stress.

What material to use?

Often people will use austenitic stainless steel for products where there is a risk of CSCC. However, there is still a risk that it can happen. While the alloys have high corrosion resistance, there can be problems at the grain boundary because of the presence of chromium carbide. This has less resistance to the corrosion than chromium. It can be an issue due to welding or the use of certain heat treatments.

A better option is to choose a nickel such as alloy C276. The high nickel content here ensures it is immune to CSCC. Plus the inclusion of tungsten in the alloy helps to inhibit pitting corrosion. If that wasn’t enough, a high content of molybdenum and chromium pushes the resistance even higher. In all it is the perfect material for use in challenging industries, including gas and oil, nuclear, and more.

Is there anything else that can help?

The other thing people can do to tackle the issue is to control the conditions. Firstly they can look to reduce the amount of chlorides and oxygen in the environment. Minimising them can remove two of the main elements that cause CSCC. Then, if possible, they can look to reduce the temperatures and pressure or stress on products.

Ordering nickel alloy round bar in alloy C276

Brindley Metals works to supply the perfect materials for various needs and conditions. Our range includes plenty of useful options, including alloys of titanium and aluminium. Plus we have more specialist metals too.

We are proud to include nickel alloy round bar in alloy C276 in our range. The bars are available in different diameters to suit an array of applications. This can include uses in tricky industries where CSCC is a concern.

So, if you want to order quality materials from a specialist in the UK, contact us.

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