Seamless steel pipe and spiral steel pipe are two completely different types of steel pipe. Their main differences lie in manufacturing process, structural characteristics, performance, and application areas. Nansteel Manufacturing Co., Ltd has carefully summarized the four major differences between seamless steel pipe and spiral steel pipe.
Manufacturing Principle: Solid billets are used as raw materials and are formed into a single piece through plastic processing such as piercing, rolling, cold drawing, or cold rolling. The pipe body has no welds.
Features: The pipe body has a continuous and dense structure, without stress concentration points caused by welding.
Spiral Steel Pipe
Manufacturing Principle: Steel strip coils are used as raw material, which are then rolled into a circular tube using a spiral forming machine. Double-sided submerged arc welding is then performed on the formed spiral seam.
Features: The pipe features one or more spiral welds, each several times the length of the pipe.
2. Structure and appearance
Seamless steel pipe: Features a smooth appearance, a straight tube body, and no weld marks.
Spiral steel pipe: Features a clearly visible spiral weld seam on the surface, typically present on both the inside and outside.
3. Performance and application
Seamless steel pipe
Strength and pressure bearing: Higher, because there is no weld, the pipe body has good integrity, can withstand higher pressure and greater stress, and is not easy to crack.
Application areas: Suitable for high-pressure, high-temperature, high-strength fluid transportation and structural purposes, such as: high-pressure boiler pipelines, oil and gas transportation main pipelines, hydraulic systems, chemical pipelines, etc.
Dimensions: Due to manufacturing process limitations, the caliber is usually small and the wall thickness has a certain range.
Spiral steel pipe
Strength and pressure bearing: The weld is the weak point in its structure. Although double-sided welding can enhance the strength, it is still not as good as seamless steel pipe. However, its excellent dimensional adaptability enables it to meet the requirements of large diameter and low pressure.
Application areas: It is suitable for large-diameter, low-pressure fluid transportation and structural purposes, such as: tap water pipes, heating pipes, large-scale water supply projects, oil and gas pipelines (but in situations where the pressure requirements are lower), piling, structural support, etc.
Dimensions: The caliber range is very wide, and large-diameter and ultra-large-diameter steel pipes can be produced, which is its main advantage.
4. Cost
Seamless steel pipe: The production process is complex and requires high raw materials, resulting in higher costs. This is especially true for large diameters, where the manufacturing cost of seamless steel pipe rises sharply.
Spiral steel pipe: Using steel coils as raw material, the production process is relatively simple and efficient. This offers significant cost advantages, especially in the production of large diameter steel pipes, resulting in lower prices.
Summary and selection recommendations
Seamless steel pipes are the first choice for projects that pursue high safety, high pressure and high strength, such as in petrochemical, power boiler and other fields with strict safety requirements.
Spiral steel pipes are an ideal choice for projects that require large diameters and low costs, such as urban water supply and drainage, and large building structure support.
In short, the choice of seamless steel pipe or spiral steel pipe mainly depends on the project's working pressure, pipe diameter and budget.
Read more: Is Seamless Steel Pipe Easy to Weld?
1. Manufacturing process
Seamless Steel PipeManufacturing Principle: Solid billets are used as raw materials and are formed into a single piece through plastic processing such as piercing, rolling, cold drawing, or cold rolling. The pipe body has no welds.
Features: The pipe body has a continuous and dense structure, without stress concentration points caused by welding.
Spiral Steel Pipe
Manufacturing Principle: Steel strip coils are used as raw material, which are then rolled into a circular tube using a spiral forming machine. Double-sided submerged arc welding is then performed on the formed spiral seam.
Features: The pipe features one or more spiral welds, each several times the length of the pipe.
2. Structure and appearance
Seamless steel pipe: Features a smooth appearance, a straight tube body, and no weld marks.
Spiral steel pipe: Features a clearly visible spiral weld seam on the surface, typically present on both the inside and outside.
3. Performance and application
Seamless steel pipe
Strength and pressure bearing: Higher, because there is no weld, the pipe body has good integrity, can withstand higher pressure and greater stress, and is not easy to crack.
Application areas: Suitable for high-pressure, high-temperature, high-strength fluid transportation and structural purposes, such as: high-pressure boiler pipelines, oil and gas transportation main pipelines, hydraulic systems, chemical pipelines, etc.
Dimensions: Due to manufacturing process limitations, the caliber is usually small and the wall thickness has a certain range.
Spiral steel pipe
Strength and pressure bearing: The weld is the weak point in its structure. Although double-sided welding can enhance the strength, it is still not as good as seamless steel pipe. However, its excellent dimensional adaptability enables it to meet the requirements of large diameter and low pressure.
Application areas: It is suitable for large-diameter, low-pressure fluid transportation and structural purposes, such as: tap water pipes, heating pipes, large-scale water supply projects, oil and gas pipelines (but in situations where the pressure requirements are lower), piling, structural support, etc.
Dimensions: The caliber range is very wide, and large-diameter and ultra-large-diameter steel pipes can be produced, which is its main advantage.
4. Cost
Seamless steel pipe: The production process is complex and requires high raw materials, resulting in higher costs. This is especially true for large diameters, where the manufacturing cost of seamless steel pipe rises sharply.
Spiral steel pipe: Using steel coils as raw material, the production process is relatively simple and efficient. This offers significant cost advantages, especially in the production of large diameter steel pipes, resulting in lower prices.
Summary and selection recommendations
Seamless steel pipes are the first choice for projects that pursue high safety, high pressure and high strength, such as in petrochemical, power boiler and other fields with strict safety requirements.
Spiral steel pipes are an ideal choice for projects that require large diameters and low costs, such as urban water supply and drainage, and large building structure support.
In short, the choice of seamless steel pipe or spiral steel pipe mainly depends on the project's working pressure, pipe diameter and budget.
Read more: Is Seamless Steel Pipe Easy to Weld?
