Differences between straight seam welded pipe and seamless pipe

As two important categories in the steel pipe market, straight seam welded pipe and seamless pipe have significant differences in production technology, application fields, performance characteristics, etc. This article will discuss the differences between straight seam welded pipe and seamless pipe in detail from these aspects.

1. Differences in production technology

The production process of straight seam welded pipe is relatively simple and direct. It mainly forms a steel pipe by curling the steel plate or strip into a cylinder and then welding the joints together through a welding process. In this process, the weld is a significant feature of the straight seam welded pipe and one of the main differences between it and the seamless pipe. According to different welding methods, straight seam welded pipes can be divided into arc welded pipes, high-frequency or low-frequency resistance welded pipes (ERW pipe), gas welded pipes, furnace welded pipes and other types. Among them, high-frequency resistance welded pipes are widely used because of their high production efficiency and low cost.

In contrast, the production process of seamless pipes is more complicated. Seamless pipes are usually made of solid pipe blanks (such as round steel) through perforation, hot rolling, cold rolling or cold drawing. These processes ensure that seamless pipes do not produce welds during the manufacturing process, giving them higher integrity and strength. The production of seamless pipes has high requirements for raw material quality, process control and equipment precision, so its production cost is relatively high.

2. Comparison of performance characteristics
In terms of performance characteristics, seamless pipes have excellent pressure resistance and firmness due to their weld-free design. When the diameter and wall thickness are equal, the pressure and firmness of seamless pipes are much greater than those of straight seam welded pipes. This feature makes seamless pipes have higher safety and reliability in harsh environments such as high pressure, high temperature and high corrosion. Therefore, in the oil, natural gas, chemical, and electric power industries, seamless pipes are widely used in key components such as pipelines, boiler tubes, and heat exchangers.

Although straight seam welded pipes have welds during the production process, modern welding technology has been able to ensure that the quality of the welds reaches a higher standard. However, since the mechanical properties of the welds are lower than those of the parent material, the use of straight seam welded pipes under extreme conditions such as high pressure and high temperature is subject to certain restrictions. However, straight seam welded pipes have the advantages of high production efficiency, low cost, and a variety of varieties and specifications, which make them have broad application prospects in low pressure, normal temperature, and general corrosive environments. For example, in the fields of construction, agriculture, and machinery manufacturing, straight seam welded pipes are used as scaffolding pipes, greenhouse pipes, fluid delivery pipes, etc.

3. Different application fields
Due to the difference in performance characteristics, straight seam welded pipes and seamless pipes also have different application fields. Seamless pipes are more suitable for high pressure, high temperature, high corrosion and other occasions due to their excellent pressure bearing capacity and firmness. For example, in oil and gas pipelines, seamless pipes are favored for their good sealing and pressure bearing capacity. In addition, seamless pipes are also widely used in boiler manufacturing, chemical equipment, power equipment and other fields.

Straight seam welded pipes are widely used in low pressure, normal temperature, and general corrosive environments due to their low cost and high production efficiency. In the field of construction, straight seam welded pipes are used as scaffolding pipes, supporting structures, etc.; in the field of agriculture, straight seam welded pipes are used as greenhouse frames, irrigation systems, etc.; in the field of machinery manufacturing, straight seam welded pipes are used as fluid conveying pipes, structural parts, etc.

Conclusion:
There are significant differences between straight seam welded pipes and seamless pipes in production technology, performance characteristics, and application fields. Seamless pipes occupy an important position in high pressure, high temperature, high corrosion and other high-demand occasions with their excellent pressure bearing capacity and firmness; while straight seam welded pipes are widely used in low pressure, room temperature, and general corrosive environments with their low cost and high production efficiency. In practical applications, the appropriate type of steel pipe should be selected according to specific needs and conditions to ensure the safety and economy of the project.

With the continuous advancement of science and technology and the continuous improvement of technology, the production technology of straight seam welded pipes and seamless pipes will be further improved. In the future, both will play a more important role in their respective application fields and provide more solid support for the development of all walks of life.

Read more: ERW pipe vs Seamless pipe cost or Types and uses of welded steel pipe