Steel pipes are traditionally being used for conveying water and gases because of their hollow structure associated with strength, durability and elasticity. Steel pipes are beneficially used where high resistance is required to withstand internal and external pressure. Even under the toughest condition, steel pipes can be used because of the elasticity, ductility and freedom from brittleness. Steel pipes are usually manufactured from materials with yield stresses varying within 210 to 350 MPa and tensile strength varying within 340 to 650 MPa. As a result, steel pipes have the ability of accommodating handling stresses, uneven bending, wrong alignment or variation in temperature. Steel pipes can more beneficially be used where complicated bending and longitudinal stresses are involved.
Steel pipes can beneficially be used where high resistance is required against shock or vibration. Fluctuating pressure involved in static head or shock pressure arising from water hammer can be withstood by the use of steel pipes. Steel pipes are used in water pipes, fire sprinkler systems and pipe networks that carry flammable gases. Carbon steel pipes with carbon contents are subjected to rusting and the consequent corrosion. Due to atmospheric oxidation, ferric oxide is formed that separates away from the surface as flakes. This surface corrosion is arrested in stainless steel pipes or in galvanized steel pipes. In the former case chromium is alloyed with steel and the surface coating of chromium oxide arrests further corrosion. Similarly, galvanized steel pipes, with surface coating of zinc checks rusting of steel pipes when exposed to the atmospheric condition.
After rinsing out rusted surface in acid, steel pipes are dipped into a bath of molten zinc and kept there for some time. The internal as well as the external surface of the pipes get a thinner film of zinc and such pipes are called galvanized pipes. The galvanized steel pipes of various nominal bores are used as water pipes by laying them underground for supply of water for public utility. Because of the anti-corrosive quality of zinc, water does not react with steel and rusting and corrosion are checked. These underground water supply systems facilitated by galvanized steel pipes last longer with almost zero maintenance cost. The benefit of using Steel pipes goes to the public in the shape of saving for the local government.
Steel pipes come in a variety of forms and structures depending upon their end-use such as Steel Pipes and Tubes, Hot Dipped Galvanized Tubes, Black Steel Tubes, Fence Tubes, Scaffolding Tubes, Structural Steel Tube. Steel strips of various widths and continuous lengths are formed into tubes; the two ends are joined by welding or by Electric Resistance Welding (ERW). Usually, structural steel such as angles, channels, joists and beams are used for constructional purposes. But steel pipes can be beneficially used for roofing structure like truss because of lower cost and higher tensile strengths. Galvanized steel pipes find beneficial use in mobile towers because they are exposed to atmospheric condition. These towers can withstand higher wind pressure with the involvement of lesser material cost in the shape of galvanized steel pipes as compared to the galvanized angles.