Special topic of seamless and welded steel pipes

Stainless steel pipe and carbon steel pipe are the most commonly used standard steel pipe types today. They are part of pipes manufactured according to different codes and standards. Generally, pipes are sold as “nominal pipe size”, usually 1/8 inch to 72 inch. Whether carbon steel or stainless steel, there are two most common pipe types, namely welded pipe and seamless pipe. Through this article, let’s discuss seamless steel pipe and welded steel pipe below.

Seamless steel pipe and welded pipe

What is seamless steel pipe?

Seamless steel pipe has no joint. As the name implies, they are produced by hot rolling and cold rolling. The manufacturing process of seamless pipe does not require welding. The most common specification for seamless carbon steel pipe is A106B. Stainless steel pipe is manufactured according to A312 specification. Stainless steel pipes are also available in seamless and welded configurations. The most common stainless steel materials are 316 and 304.

About welded steel pipe

On the other hand, the welded pipe is made by rolling the steel coil to the required standard thickness, which is a manufacturing process of leaving joints on the pipe body. In the next stage, the joint shall be cut to the width corresponding to the pipe size to be constructed. In particular, welded pipes are also known as ERW (resistance welding) pipes. The most common specification for welded carbon steel pipe is A53.

Advantages of welded pipe and seamless steel pipe

Each pipeline has advantages and disadvantages, depending on your end use. Although the seamless joint has a high pressure rating, it may not be the highest priority of the project. If you are building a bridge and need a lot of piles, it may be more important to weld pipes with lower cost and larger potential size.

List the advantages of welded steel pipe below:

1. The size range of electric welded steel pipe is large, and it can produce welded pipe with diameter of 45 to 4000 mm, wall thickness of 0.1 to 40 mm and pipe length of hundreds of meters. The wall thickness is smaller than that of seamless steel pipe and furnace pipe. The ratio of pipe diameter to pipe wall thickness can reach 100.
2. The appearance of new electric welding devices, equipment and control systems has been continuously improved, which makes the weld have higher strength than the metal base. The use of heat treatment eliminates the welding stress of the weld and allows the welded pipe to obtain uniform structure on the cross section.

Seamless steel pipe and its advantages

1. Seamless steel pipe also includes large-diameter seamless steel pipe and small-diameter seamless steel pipe, and furnace welded pipe is also very small. Generally, the pipe diameter is 4 to 50. The wall thickness is 5 to 28.
2. They can usually withstand greater pressure, which makes them an ideal choice for oil and gas industry applications. If the pipe is in the visible area, there will be no joints exposed to corrosion and it will not look ugly. Due to the limitation of the production process, when you need a really big pipeline, this is not a good choice.