As we are all aware of, the piping system is crucial in the oil and gas industry. But, the pipes used to convey various types of processes or substances through them. But, here, we will see one of the categories of pipes based on its manufacturing. Pipes are usually manufactured in 2 ways – seamless pipe and welded pipe. We will limit our scope of explanation to the welded pipe manufacturing process here.
Various methods used for welded pipe manufacturing
Electric Resistance Welding (ERW) Process
In the Electric Resistance Welding (ERW) process, a flat sheet of steel is cold-formed into a cylindrical shape to manufacture pipe. Then current is applied to either edge of the steel cylinder, and the steel is heated to the point that the edges forcibly form a bond without welding filler material.
This type of welded pipes are majorly used for low/ medium pressure applications such as transportation of water/oil.
The two major types of Electric resistance welding are –
- High-Frequency Welding
- Rotary Contact Wheel Welding.
This topic forms an integral part of the oil and gas courses for mechanical engineers.
Submerged Arc Welding (SAW) Process
In the Submerged Arc Welding (SAW) process, an arc is formed between a continuously fed bare wire electrode and the workpiece. There is also the use of flux to produce protective gases and slag and add alloying elements to the weld pool. Shielding gas is not necessary.
The types of Submerged Arc Welding (SAW) processes are:
- Longitudinal Submerged Arc Welding (LSAW) Process
- Spiral Submerged Arc Welding (SSAW) Process
Electric Flash Welding Process
The Electric Flash Welding Process involves the conversion of a sheet of steel into a cylindrical shape. Here, the edges are heated until they turn semi-molten and then are forced together until molten steel is forced out of the joint and forms a bead.
But the disadvantage of this type of manufactured pipe is the susceptibility to corrosion and hook cracks. This type of pipe is also susceptible to failures due to hard spots in the plate steel due to the steel’s accidental quenching during the manufacturing process.
This manufacturing process is not used anymore in pipe manufacturing, and you won’t find it in many online courses for piping engineering.
How to know whether it’s a Seamless or ERW Stainless Steel pipe?
To identify that a pipe supply is seamless or ERW welded, read the stencil on the side of the pipe
If it is ASTM A53, −
Type S means seamless. −
Type F is furnace but welded. −
Type E is Electrical resistance welded.
This is the easiest way to identify whether a pipe is seamless or Electric Resistance Welded Pipe.
Before deciding on any oil and gas training courses online, you must check your interest, the course curriculum and the quality of the material provided.
To understand various other aspects of the pipe manufacturing process, you can check the oil and gas piping engineering course.
by Debashree P
Debashree is an Aeronautical engineer by education and a curious researcher by passion. She is passionate about engineering and technology. She is an avid technology writer who has a knack for developing content for websites, newsletters, blogs, articles, advertising and marketing materials based on the requirements. Technologies of her interest include Aviation, Oil & Gas and AI.