A steel tube, also known as a steel pipe, is a type of building material that is primarily used for transporting liquids and gases. It consists of a hollow, cylindrical shaped object that can vary in length depending on the application. These tubes are used both above and below ground, and are found in both commercial and residential plumbing systems.
Many different types of steel can be used to manufacture a steel tube. Carbon or cold-rolled steel is the most common, and also among the most affordable. A steel tube may also be coated with zinc in a process known as "galvanization," which helps to improve the strength and corrosion-resistance of the pipe. Stainless steel pipes are blended with chrome to add corrosion resistance, though these pipes tend to be the most expensive. Finally, corrugated steel tubes are among the largest types of piping, and have a spiral-like texture that gives them extra strength and durability.
Depending on how it's made, a steel tube may have a seam running along its length, though seamless models are also available. Seamed models are made by bending sheets of steel around a cylindrical form. The pipe is then welded along the seam. Seamless models are made using an extrusion process, and tend to work better in high-pressure applications.
While steel pipes are typically used to carry water, they can also be used to transport gases, wastewater, or industrial liquids. Small steel tubes are frequently found in laboratory settings, and some are even used as a conduit for transporting electrical wiring and cables. A steel tube can also be used as a structural framing member when building furniture, equipment, scaffolding, or other structures.
Tubes are often chosen based on their size, which includes an inside diameter, outside diameter, and wall thickness. The diameter of the tube must be carefully chosen based on friction and pressure levels within the plumbing system, while the wall thickness determines the strength and durability of the pipe. In many regions, tube size is given using a value of schedules, where higher schedule values are associated with thicker pipe walls. Typically, the outside diameter of the pipe is fixed, so as schedule values increase, inside diameter decreases.
Steel tubes offer a number of advantages over other pipe materials. They are known for their high level of strength and durability, and are capable of handling high levels of pressure and relatively high temperatures. Many steel tubes are considered suitable for transporting potable water, as well as liquid and gaseous chemicals.
At the same time, steel tubes are often more expensive than other types of tubes, particularly thermoplastic products. They are more susceptible to rust and corrosion, and are more difficult to cut and join. Because of their relatively high weight, steel tubes also take longer to install than more lightweight thermoplastic models.