Different industry sectors

The construction, oil and gas, water, manufacturing and energy industries are the main sectors where pipe welding is used. It is a specialised technology that plays an extremely important role in ensuring the stability and efficiency of operations in these sectors. The pipe welding process requires an in-depth knowledge of different techniques, materials and working conditions to meet safety and quality requirements.

The importance of appropriate techniques

In order to weld pipes efficiently and safely, manufacturers need to master many different techniques. Application, temperature, and the availability of filler material are just some of the factors that influence the choice of the right approach. Understanding these processes is key to producing pipes optimally. The most commonly used pipe welding techniques and the differences between them will be discussed below.

two workers welding a pipe

Benefits of the welding process

Pipe welding offers a number of benefits to manufacturers. Firstly, it eliminates the need for fittings between pipe sections, making production less labour-intensive and more cost-effective. Such pipes also have better flow, as the absence of fittings reduces resistance to fluid circulation. In addition, welded pipes are less prone to leaks and bursts, making them more reliable. What's more, they are easier and quicker to repair. Unlike pipes fused with fittings, they do not need to be disassembled or reassembled, which greatly simplifies maintenance processes.

Shielded Metal Arc Welding (SMAW)

Also known as manual metal arc welding (MMAW), this is one of the oldest welding techniques. In this method, an electrode is melted by the heat generated by an electric arc. The molten material is then applied to the surfaces of the metal pipes to join them together. The main advantage of this method is that there is no need for shielding gas or flux, making the process relatively simple and easy to use. However, SMAW also has its disadvantages. Due to its manual execution, the process is less efficient than other methods and the quality of the weld depends on the skill of the welder. The stability of the arc, the depth of fusion and the positioning capabilities of the weld are key factors affecting the effectiveness of this technique.

welding of pipe

Gas metal arc welding (GMAW)

Also known as MIG (Metal Inert Gas Welding) and MAG (Metal Active Gas Welding), Gas Metal Arc Welding (GMAW) is a more advanced technique that uses shielding gas to protect the electrode and the parts being joined. This method is faster and more efficient than SMAW because it uses partially or fully automated equipment. The main advantages of GMAW are:

  • high metal deposition rate
  • minimal risk of welding defects such as trapped slag.

However, GMAW requires constant voltage and power supply, which can be challenging in field conditions. Additionally, the technique does not work well outdoors, as the shielding gas can be dispersed by the wind.

Flux Cored Arc Welding (FCAW)

The FCAW technique, or flux-cored arc welding, joins parts by means of heat generated by an electric arc. There are two versions of this method - self-shielded FCAW and gas-shielded FCAW. Shielded gas FCAW is more efficient, but has the disadvantage that the gas can dissipate in windy conditions, which can lead to porosity in the weld. Self-shielded FCAW, on the other hand, eliminates the gas problem but is less efficient in terms of metal deposition speed. The advantage of this technique is its mobility and ability to work outdoors, making it ideal for thicker materials.

SAW method

Submerged arc welding (SAW) is a semi-automatic method in which the electric arc is shielded by a layer of flux. This process is characterised by the highest metal melting speed and high weld quality. The SAW technique is mainly used in the production of line pipes and pressure vessels, where longitudinal and circumferential butt welds are required. The main difficulty with this method is tracing the arc, which is 'submerged' under the flux, making the process more complicated to perform. However, properly trained welders are able to achieve excellent results, and the technique is particularly effective in large industrial projects. 

welder at work

Tungsten inert gas welding

TIG, or tungsten inert gas welding, also known as GTAW, is one of the most precise welding techniques. It is widely used for joining non-ferrous metals and for projects requiring high quality welds. The method uses a non-fusible tungsten electrode, which produces very precise and clean welds. It is worth mentioning that TIG is a time-consuming and skill-intensive process. Due to the slower pace of work and higher equipment and labour costs, this technique is mainly used for specialised projects where weld quality is important. 

Choosing the right method

Choosing the right pipe welding technique depends on a number of factors, such as the material, the working conditions, as well as quality and productivity requirements. Each of the methods described - from SMAW to TIG - has its own advantages and limitations, so it is important for manufacturers and welders to carefully select a technique for a specific project. With the right choice, not only can high quality joints be achieved, but production efficiency and operational safety can also be increased.

FAQ:

Why is pipe welding important?

It provides long-lasting connections, essential in sectors such as construction, oil, gas and energy. This ensures that systems function efficiently and safely, minimising the risk of leaks.

Is welding better than fittings?

It reduces flow resistance and the risk of leakage, and improves the performance of the pipes, making them more durable and cheaper to maintain as they do not need to be dismantled or seals replaced, minimising service costs.

What are the advantages and disadvantages of SMAW?

SMAW has the advantage of simplicity and mobility, as it does not require shielding gas. The disadvantages are the lower productivity and the dependence of quality on the skill of the worker, which can make it difficult for less experienced people to achieve high quality welds.

When to use FCAW?

FCAW is ideal for working outdoors and with thick materials as it does not require shielding gas. It has high mobility, although it can generate more smoke, which may require additional personal protective equipment in confined spaces or where ventilation is limited.