Seamless pipe is of strip shape with hollow core and there is no seam on the around surface. Seamless pipe is used for transporting petroleum, natural gas, coal gas, water and some solid substances. Compared with other solid steel, steel pipe is an economical material for its less weight while they have the same breakaway thrust and is widely used in manufacturing component parts and mechanic parts like drilling stem in petroleum exploring filed, actuator of car, and frame of bike falsework in the worksite. Making circular parts from steel pipe can make full use of the materials, simplifying manufacturing procedure, saving materials and time. Products like rolling bearing ferrule and jack cover have been widely manufactured from steel pipe. Steel pipe can also be used to make conventional weapons, such as the tubes of guns or cannons. By the difference of the shape of cross section of steel pipes, they can be classified as Circular pipe and Special section pipe. As Circular pipe has the larger area when having the same perimeter as the special section pipe, it can transport more fluid. Besides, the inner pressure is well distributed on the interior wall of the pipe, so most steel pipe is of circular type. Size range: from 114.3mm to 508mm WallThickness range: 5.21-16.13mm Standard: API5L B
Welded pipe is steel pipe formed by welding two pieces of pipe models together which are manufactured by rolling the steel plate or steel belt. Manufacture of welded pipe has such features as simple procedure, high production efficiency, various types, and low costs. However, its strength is less than that of Seamless pipe. Since 1930s, with the continuous development of steel rolling and the improvement of inspection as well as promotion of quality of welding seam, Welded pipe has substituted Seamless pipe in many fields and developed many types. According to the shape of welding seam, welded pipe is classified as ERW pipe and SAW pipe.
ERW pipe has a quick development for its simple producing procedure, high production efficiency as well as low cost. SAW pipe usually has higher strength than ERW pipe, so it can be made into larger bore pipe from smaller pipe model. SAW pipes of various bores can be made from pipe models of the same bore. However, compared with ERW pipe with the same length, its welding line increases by 30% to 100% and has low production efficiency. Thus, welding pipe with smaller bore usually adopts linear welding method while the larger bore pipe adopts spiral welding method. Size range: from 219mm to 2032mm Wall thickness range: 5-18mm Standard: API5L B X42 TO X70 Grade
Standards applied : ISO3183-3、API Spec 5L、GB9711 etc.
Use: The transportation of gas (both on land and underwater), coal fluid, and ore fluid, the component parts used in ocean platform, power station, chemical field and cities. Main features:
1.Its bore has been expanded by machine. As the inner stress is little and well distributed, it can efficiently avoid crack resulting from corrosion. Accurate sizes guarantee the smooth construction at worksite. 2.Adopting carefully weld after previous weld method guarantees the stable welding procedure and high quality of seam. 3.NDT is easily carried out during the manufacturing procedure and installation period in the open air. 4.Compared with the non-linear seam pipe, it has a shorter seam with little problem. 5.Wider type ranges: Both small bore with thick wall thickness and big bore with thick wall thickness can be manufactured.
Seamless pipe is of strip shape with hollow core and there is no seam on the around surface. Seamless pipe is used for transporting petroleum, natural gas, coal gas, water and some solid 
substances. Compared with other solid steel, steel pipe is an economical material for its less weight while they have the same breakaway thrust and is widely used in manufacturing component parts and mechanic parts like drilling stem in petroleum exploring filed, actuator of car, and frame of bike falsework in the worksite. Making circular parts from steel 
pipe can make full use of the materials, simplifying manufacturing procedure, saving materials and time. Products like rolling bearing ferrule and jack cover have been widely manufactured from steel pipe. Steel pipe can also be used to make conventional weapons, such as the tubes of guns or cannons. By the difference of the shape of cross section of steel pipes, they can be classified as Circular pipe and Special section pipe. As Circular pipe has the larger area when having the same perimeter as the special section pipe, it can transport more fluid. Besides, the inner pressure is well distributed on the interior wall of the pipe, so most steel pipe is of circular type.
Welded pipe is steel pipe formed by welding two pieces of pipe models together which are manufactured by rolling the steel plate or steel belt. Manufacture of welded pipe has such features as simple procedure, high production efficiency, various types, and low costs. However, its strength is less than that of Seamless pipe. Since 1930s, with 
the continuous development of steel rolling and the improvement of inspection as well as promotion of quality of welding seam, Welded pipe has substituted Seamless 
pipe in many fields and developed many types. According to the shape of welding seam, welded pipe is classified as ERW pipe and SAW pipe.
Standards applied : ISO3183-3、API Spec 5L、GB9711 etc.
1.Its bore has been expanded by machine. As the inner stress is little and well distributed, it can efficiently avoid crack resulting from corrosion. Accurate sizes guarantee the smooth construction at worksite.