Waterside failure mechanism problems

We are an establishment that has been providing exception tubing manipulation services for several years. Using techniques such as tube expansion, we supply tubes that meet your requirements. Furthermore, we can work with numerous materials to suit differing applications. At the end of the day, ours is a very comprehensive range of solutions.

One common use of tubing is boiler components. Boiler tube failure is something you might come across in your lifetime. You may have gotten a repair of a leak only to find you need to turn the appliance off due to another one. By pinpointing and correcting the root cause of these leaks, you can minimise the chance of future failures.

A full inspection is the best way to find the root cause of the problem. Tubing failures are typically symptoms of other complications. To properly understand why things fail, you need to examine all the elements of boiler operation leading to failure.

There are multiple boiler tube failure mechanisms. They frequently occur on contemporary operating boilers. The ones we will be concentrating on are waterside failure mechanisms. Read on to learn more and then contact us if you need tube expansion or other services.

Caustic attacks

Tube expansionThe first waterside failure mechanism issue we have is a caustic attack. Symptoms include a localised wall loss on the inside diameter (ID) surface of your tubing. What you end up with is higher stress and strain in your tube wall.

As for the causes, caustic attacks happen when there is considerable deposition on ID tube surfaces. This results in lower cooling water flow coming into contact with your utensils. In turn, it results in local under-deposit boiling and boiler water chemical concentration. That can lead to a caustic condition. It corrosively attacks and breaks down the protective magnetite on the tube.

If you are looking for solutions, you need to stop the gathering of large deposits. It is also a good idea to control the water chemistry. Phosphate boiler water treatments can be useful here. Come to us if you require tube expansion services.

Oxygen pitting

Symptoms on pitting include aggressive localised boiler tube corrosion. There is also the loss of tube wall. Pits can function as stress concentration sites. These can become initiation points for stress-related corrosion mechanisms.

Oxygen pitting happens when there is considerable oxygen in boiler water. It can happen during operations thanks to in-leakage of air at the pumps. Alternatively, it can be because of the failure of the operation of pre-boiled water treatment gear. This can occur during long out-of-service times if you fail to follow the right procedures in layup.

The solution here is to follow the right layup processes when there are boiler outages. Furthermore, you should enhance oxygen control during boiler operation and start-ups.

Corrosion fatigue

The last issue we will go over is waterside corrosion fatigue. Symptoms include huge transgranular cracks that normally happen adjacent to external attachments. Expect thick-lipped failures, which initiate from ID cracks. Cracking will often be perpendicular to the direction of the stress.

With the causes, tube damage happens because of a mixture of corrosion and thermal fatigue. This largely comes down to the boiler operation and design. Other influences are boiler water oxygen content and water chemistry. A combination of such effects causes the breakdown of the protective magnetite you find on the boiler tube’s ID surface. When the tube loses this, it becomes vulnerable to corrosion.

The solution to the problem is to limit the number of cycles. Moreover, you should reduce the constraints on tubes and lower the dissolved oxygen during start-up.

You can count on us for tube expansion and more

At Multiform Tubes Engineering Ltd we work to provide tubes that are suitable for many distinct jobs. For example, they can be useful across many industries and in domestic settings too. What’s more, we can work with various materials like stainless steel, brass, and aluminium.

So, if you would like to find out more about tube expansion or anything else we do, feel free to contact us. We can advise you about any service you may need.