Structural steel pipe and tube ,welded steel pipe and seamless steel pipe

Rejected pipe which cannot be classified as a prime product because of some physical or chemical defect is sold by the mills to steel pipe distributors, distributors of steel products, fabricators, and consumers. These structural steel pipes and tubes are available in CW, ERW, DSAW and seamless, in all sizes, weights, and classes of material. Although reject pipe carries no warranty whatsoever, it can have application for structural purpose. 
Few of the typical examples where reject pipe has been used as structural steel tubing and pipes are handrails, columns, posts, piling, sand-wash, casing, culverts, fence, caissons, sign poles, bumpers, bracing, parking meter posts, towers, supports, rollers, etc. Structural steel pipes and tubing are normally priced substantially under prime pipe and can affect large savings in the right application.
The steel pipes or tubes used for engineering structures made in a heated furnace or open-heart with thickness of 11mm or less are called “Structural Steel Pipes”. These pipes are generally used where plant-fabricated pipe cannot be installed and do not have the strength to support the loads imposed on them. Structural steel pipes and tubes can be knocked-down, bolted together at the site where it is to be used. These are the pipes which does not meet the rigid requirements of the intended specification due to some chemical or physical flaw is known as structural pipe. It can be rolled into different shapes and used for construction. These pipes are also called as “infrastructural pipes”.
Structural steel tubes come in various shapes with circular, square and rectangular cross-sections which can be used for drainage pipe, small bridges or numerous other construction or industrial applications. The application ranges from culverts, sub-drains, sewers, service tunnels, etc. Structural Steel pipe and tubes governs the chemical and mechanical properties of structural steels and are best suited for general construction and engineering purposes. 
The selection of the proper grade (type and strength level) is important for a particular application. Due to their low weight, the structural steel pipes offer better resistance to torsional stresses and sagging. These pipes or tubes are easy to set up with simple welded joints. The comparatively small exterior surface area without sharp angles or burrs ensures easy maintenance and protection against corrosion. The HSS steels are stronger and can bear more loads which is why it could be used as beams. 
Those pipes, which does not meet the rigid requirements of the intended specification due to some chemical or physical flaw are known as structural pipe. Structural steel pipes and tubes are those which can be knocked-down and are then bolted together at the site, where it is to be used. These pipes are generally used where plant-fabricated pipe cannot be installed, are not big enough or do not have the strength to support the loads imposed on them. 
Structural steel tubes come in various shapes with circular, square and rectangular cross-sections and are used for drainage pipe, small bridges or numerous other construction or industrial applications. The application ranges from culverts, sub-drains, sewers, service tunnels, etc. Structural Steel pipe and tubes governs the chemical and mechanical properties of structural steels and are also used for general construction and engineering purposes.