How to distinguish pipe and tube and what characteristics do they have?

You may have heard the term pipe and tube and often see them in advertising, but you may not be clear about what is the difference between them. Most people, even experts in the relevant industry, in fact, do not know. Pipes and tubes have similar shapes that look very similar, but you will be surprised to find that there are many differences between them.

Diameter and thickness

In the method of diameter measurement, pipes and tubes are different. Diameter of the pipe is generally referred to the internal diameter, rather than the actual outside diameter. In contrast, the diameter of the measuring tube is the actual outside diameter.

How the wall thickness of the pipe and tube is measured has been an important factor. Schedules is used to signify the pipe wall thickness. Different schedule express different diameter. If the schedule number is larger, the diameter of wall is thicker. Thereinto, tubing wall thickness is measured by gauge number for thinner tubes and by fractions for thicker walled tubes.

Tolerances

There are differs in tolerances between pipe and tube. Comparing with pipe, the tolerance of tube is commonly tighter. Tolerance includes diameter tolerance, wall thickness tolerance, straightness tolerance, and roundness tolerance.

Mechanical & Chemical properties

The pressure rating, yield strength, and ductibility properties are important to pipes. While, in terms of tubes, the hardness, tensile strength and high precision are the key to maintain high quality. The elements like C, Mn, S, P, Si are main chemical elements for pipes, and few micro-elements requirements are needed also. But for tubing, the micro-elements are very important to the quality and process.

Packing

Pipes are delivered in bundle or just delivered as bulk. The reason is that for pipes, the key job is to protect the pipes surface from serious damage, rather than any light chafing. While, in order to well protect tubes, they are always wrapped with wooden box or thin film for each of them, especially for medical-used tubes.

Surface protection

Pipes need to be painted or coating to anti corrosion or oxidation when applied in outdoor and underground transporting. Tubes are sour cleaning and special polish treatment is needed for special using.

Quantity

Owing to long distance applications, the demand of pipes are in mass quantity. In contrary, the amount needed in application of tubes are not as large as pipes.

Pipe end & Tube end

The end between pipe and tube is different. Pipe ends shaped in plain or beveled so as to welding. However, tube ends are often with coupling ends; sometimes, specially end finish is also possible, like irregular ends, screw thread, etc.

Connection

There are two ways for pipe connecting: one is threading the ends and screwing together with couplings. Another way is welding them together or to other components, such as flanges.

However, tubes can be connected by flaring, brazing, tube couplings, or welding. The type of coupling used is decided by pressures within the tube.

Uses of pipes and tubes

In terms of use, liquids and gases is normally transported by pipe such as water, oil, natural gas, or propane. Pipe sizes and schedules are specified for the application depending on the internal pressure required of the material being transported, the volume of flow required and the material it is made of (if corrosion is an issue).

So many applications including structural, high pressure hydraulic systems, medical & food systems, boilers & heat exchangers, as well as several others adopts tube. Different from the pipe, many more grades of material and sizes is used to manufacture tube, for example, it can also be square or rectangular in shape.

Conclusion

You must have known how to distinguish them. Its meaning lies in determining what you need before you start a project to get the right type of pipe or tube.

TICO OCTG products offer professional pipe and tube, which grades and API standards is also detailed. At the same time, technological process can be clear at a glance. As a professional OCTG supplier, our products have been recognized by the oilfield tubular goods. If you interested in our products, looking forward to hearing from you.