The key difference is that a pipe is a round shape used to transport fluids and gases, and measured by nominal pipe sizes showing the pipe conveyance capacity, while a tube can be round, rectangular, squared or oval hollow section measured by outside diameter and wall thickness and used for instrumental/mechanical purposes.

What is Pipe?

Pipes are hollow cylindrical shape with a round cross-section to transport materials such as fluids, gas, pellets, powders etc. Pipes are measured by the outer diameter (OD) together with the wall thickness (WT). The dimensions are used to measures the conveyance capacity of the pipe.

What is Tube?

Tubes can be round, square, rectangular and oval hollow sections. Tubes are used for various other purposes such as pressure equipment and can also be used for mechanical and instrumentation purpose.

Ten key differences between tube and pipe

#1- Dimensions

Steel pipes are measured by the outer diameter (OD) combined with the wall thickness (WT). Outer diameter minus two times wall thickness determine the inside diameter (ID) of a pipe. It is then used to determine a rough estimate of the liquid capacity for the pipe.

For tubes, both outside diameter (OD) and the wall thickness (WT) is used to calculate the dimensional value of the hollow section.

#2- Wall Thickness

The pipes thickness is designated with a “Schedule” value. The most common are Sch. 40, Sch. STD., Sch. XS, Sch. XXS). It is to be noted that the two pipes of different NPS and same schedule have different wall thicknesses.

Steel tubes wall thickness can be represented in inches or millimetres like pipes, but can also be measured in gages.

#3- Shapes

Steel pipes are always round.
Steel tubes can be round, rectangular, square, oval etc.

#4- Production range

Steel pipes are extensive and up to 80 inches and above.
Steel tubes are narrower and range up to 5 inches, but can be larger for mechanical applications.

#5- Tolerances

Tolerances of steel pipes are being set, but rather loose, whereas, strength is not the major priority.

Steel tubes go through various quality checks such as thickness, strength and surface etc. to make sure it complies with the required tolerances. In the case of steel tubes, the main priority is mechanical strength.

#6- Production Process

Steel pipes are produced continuously, which is then stored for future sales.
Making steel tubes is a more lengthy and laborious job and mostly based on orders and customisation.

#7- Delivery time

Delivery time for steel pipes is short.
Steel tubes generally have a longer delivery time.

#8- Prices

Steel pipes are usually cheaper than steel tubes on a per tonne basis.
Price of the steel tube is higher due to high production cost owing to labour and time.
They are also produced based on stricter requirements.

#9- Materials/substrate

Steel tubes can be produced from a wide range of materials.
Steel tubes which are used in mechanical applications are mostly made from carbon steel.

#10- End Connections

The most common end connection for steel pipes are bevelled, plain and screwed ends.

For steel tubes, threaded and grooved ends are available for quicker connections on site.