Most piping systems used to transport fluids or gases require the pipe to bend or curve at some point in the length of the pipeline. Rolled pipe is an industrial method used to produce the necessary curves, bends and coils that allow metal pipes to go around corners, pass overhead or achieve the proper angle needed to make a connection.
Pipe Rolling Process
The process of pipe bending entails the application of pressure at a single point to make a single bend in a pipe. If a second bend is required the pipe is repositioned for the second bending procedure. Rolled pipe differs from bending in that pipe rolling uses multiple rollers that apply pressure to a moving pipe to achieve a continuous curve. Enormous pressure must be applied to create the curves and bends in rolled metal piping. The degree of curvature is determined by the use of one or more dies upon which the pipe is pressed by the rollers. A die is a specially formed piece of metal that is used to shape other metal objects. A large diameter die produces a more gentle curve while a smaller die makes a tighter curve. Pipe rolling is usually performed on “cold” piping, which means that the pipe is the temperature of the ambient air and is not heated as part of the rolling process.
Pros and Cons of Rolled Pipe
Rolled pipe cannot be bent into tight corners as can be achieved with standard pipe bending procedures. However, utilizing pipe rolling instead of bending allows a pipe to be formed into the necessary shape with little or no compaction of the interior diameter of the pipe. This means that the flow of material inside the pipe is not impeded and the flow pattern is not disrupted. While rolled pipe cannot be bent as sharply as standard single point pipe bending, a much greater variety of shapes can be achieved through rolling. Despite all the benefits, pipe rolling is a more complex process than pipe bending because the pipe is moving while the pressure is applied. The rate of motion may require variation throughout the process or remain constant. In some cases the dies used must also be changed at various stages to achieve the desired result.
Rolled Pipe Configurations
Pipes of differing cross sections including circular, elliptical, square or rectangular can be shaped by rolling with very little change to the structure of the pipe. The diversity of shapes and configurations that can be achieved using pipe rolling are almost limitless. Pipes can be bent into the most gradual of single curves or into S-curves, spirals, 90-degree bends and coils.
Uses of Rolled Pipe
Many manufacturing and heavy industry processes require the use of curved piping. Petroleum, natural gas, water, steam and industrial chemicals are all transported through pipeline systems. Heating, ventilation and air conditioning (HVAC) systems also require curved piping and pipe coils that can be produced by pipe rolling. Rolled piping is also used as reinforcement in automotive and construction applications.
Despite the drawback of requiring additional processing steps, pipe rolling is a widely-used and versatile method of shaping pipe. The unlimited configuration possibilities of rolled piping mean that this technology can be used to make a pipe to fit nearly any purpose.