Everything You Need to Know About Pipeline Welding

Pipeline Welding, Welding Academy NZ, Welding Techniques, Welding Processes, Welding Safety

Welding comes in different forms depending on the kind of material that needs to be welded. The parental weldment materials vary and may involve metals, thermoplastics, and even wood. In most cases, welders fuse together pipes through the heat to form a bond. Pipelines are used to supply fuel, and transport water or natural gas across towns and cities. As such, pipeline welding is a critical component of the oil and gas industry, and it requires highly skilled welders to ensure that the pipelines are built safely and efficiently.

Read on to find out more about how pipeline welding works, its common procedures, and the basic welding equipment needed.

What is Pipeline Welding?

Also known as girth welding, pipeline welding is a type of fabrication process used to assemble pipes and form a network. Pipeline welders utilize flame torches, shielded metal, and tungsten arcs to form these pieces of metal. Pipeline welding requires a specialized set of skills and knowledge, as welders must be able to weld in various positions and environments, often working in remote locations and extreme weather conditions. They must also be knowledgeable in pipeline construction and maintenance procedures, as well as relevant safety regulations and standards.

Pipe Welding Vs. Pipeline Welding

By definition, pipe welding and pipeline welding are two different processes. Pipe welding makes up massive pipe structures inside oil refineries and chemical plants. Meanwhile, pipeline welding focuses on creating a uniform and country-wide pipeline networks spread underneath roads and establishments.

Common Types of Welding Used in Pipelines

The following welding procedures are usually done in pipelines:

Shielded Metal Arc Welding (SMAW)

Manual Metal Arc (MMA) or Shielded Metal Arc Welding (SMAW) is one of the widely performed types of pipeline welding. It is also known as stovepipe welding, which uses no shielding gas or flux, thus making it more flexible and portable with lower travel speed. An electric arc generates heat to melt the electrodes to weld the pipelines. 

Flux-Cored Arc Welding (FCAW)

Unlike GMAW, Flux-Cored Arc Welding (FCAW) uses semi-automatic machines to penetrate the metals easily without needing an external shielding gas. FCAW has lower deposition rates but is ideal to perform in windy conditions and outdoor applications.

Submerged Arc Welding (SAW)

In semi-automatic Submerged Arc Welding (SAW), the electric arc forms between the workpiece and the continuously fed electrode. Tracing becomes more difficult since the arc is not visible. On the contrary, it produces flawless surfaces as compared to other pipeline welding methods.

Each technique has its own advantages and disadvantages, and the choice of technique will depend on the specific requirements of the pipeline.

How to Start Pipeline Welding?

Before the actual procedure, make sure to prepare basic pipeline welding equipment such as:

  • Power source
  • Welding guns
  • Connector cables
  • Shielding gas equipment
  • Wire feeder

Below are the steps to take before welding your pipelines:

  1. Prepare joint-butt welds in accordance with API 1104 standard guidelines.
  2. Clean the pipeline ends to remove rust, paint, varnish, or excess oil.
  3. Begin welding in the root passes after checking the preheat requirements and other specifications.
  4. Examine the welds to ensure that they are of the highest quality and that the pipeline is safe and reliable. Any defects or flaws in the welds must be identified and corrected before the pipeline is put into service.
  5. Test the pipeline by using various techniques, including hydrostatic testing and pneumatic testing. Hydrostatic or pneumatic testing involves filling the pipeline with either water, air, or gas, and pressurizing it to a predetermined level to test for leaks or defects.
  6. Administer routine checkups of welding components and conduct repairs if needed.

Why is Pipeline Welding Important?

As high-rise infrastructures continue to grow, so does the demand for skilled welders. From natural gas utilities to construction facilities, pipeline welding is essential in keeping our water and oil sources intact. Scattered across the United States, Canada, Russia, and even New Zealand are globally competitive natural gas markets, making the pipeline welding industry profitable for future generations.