Pipe & Tube

A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances that can flow liquids and gases (fluids), slurries, powders and masses of small solids.

A tube, or tubing, is a long hollow cylinder used for moving fluids (liquids or gases) or to protect electrical or optical cables and wires.

The terms “pipe” and “tube” are almost interchangeable, although minor distinctions exist generally, a tube has tighter engineering requirements than a pipe.

A fitting or adapter is used in pipe systems to connect straight sections of pipe or tube, adapt to different sizes or shapes, and for other purposes such as regulating (or measuring) fluid flow. these fittings are used in plumbing to manipulate the conveyance of water, gas, or liquid waste in domestic or commercial environments, within a system of pipes or tubes.



Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids.






Types of Pipe Fittings


Buttweld Fittings

A butt weld pipe fitting is made by the process of hot forming that includes bending and forming to shape. The starting material of butt weld fitting is a pipe that is cut to length, heated and moulded into specific shapes by means of dyes. Heat treatment is also done to remove residual stresses and obtain desired mechanical properties.

A buttweld fitting is a weldable pipe fitting that allows for change of direction of flow, to branch off, reduce pipe size or attach auxiliary equipment

Are available as elbows, buttweld pipe fittings, buttweld tee, buttweld reducer, buttweld cap & buttweld outlet

Reduces and outlets. These fittings are the most common type of welded pipe fitting and are specified by nominal pipe size and pipe schedule.

Benefits of Butt Weld Pipe Fittings

Welded connection offers a more robust connectionContinuous metal structure adds to the strength of the piping systemButtweld fittings with matching pipe schedules offer seamless flow inside the pipe.Cost-effective compared to their expensive threaded or socket weld counterparts.


Buttweld pipe fittings are most commonly available in carbon steel, stainless steel, nickel alloy, aluminium and high yield material. High yield butt weld carbon steel pipe fittings are available


Socket Weld fittings

A Socket Weld is a pipe attachment detail in which a pipe is inserted into a recessed area of a Valve, fitting or flange. Socket Weld fittings are mainly used for small pipe diameters

Weakness resistance is lower than that in butt-welded development because of the utilization of filet welds and sudden fitting geometry; however, it is still superior to that of most mechanical joining techniques.

It has various types of fittings like Socket Weld Pipe Fittings, Socket Weld Tee, Socket Weld Reducer, Socket Weld End Cap, Socket Weld Union, Socket Weld Coupling, and Socket Weld Cross & Socket Weld Outlet.


Socket Weld fittings


The pipe need not be bevelled for weld preparation.Temporary tack welding is no needed for alignment because in principle the fitting ensures proper alignment.The weld metal cannot penetrate into the bore of the pipe.They can be used in place of threaded fittings, so the risk of leakage is much smaller.Radiography is not practical on the fillet weld; therefore correct fitting and welding is crucial.Construction costs are lower than with butt-welded joints due to the lack of exacting fit-up requirements and elimination of special machining for butt weld end preparation.




The welder should ensure an expansion gap of 1/16 inch between the de pipe and the shoulder of the socket.Socket welding is unacceptable for Ultrahigh Hydrostatic Pressure (UHP) in the Food Industry application since they do not permit full penetration and leave overlaps and crevices that are very difficult to clean, creating virtual leaks.In the assembly of the joint before welding, the pipe or tube shall be inserted into the socket to the maximum depth and then withdrawn approximately 1/16″ (1.6 mm) away from contact between the end of the pipe and the shoulder of the socket.The expansion gap and internal crevices left in socket welded systems promotes corrosion and make them less suitable for corrosive or radioactive applications where solids buildup at the joints may cause operating or maintenance problems. Generally require butt welds in all pipe sizes with complete weld penetration to the inside of the piping.


Threaded Fittings

Threaded joints probably represent the oldest method of joining piping systems. Like Socket Weld fittings, threaded fittings are mainly used for small pipe diameters. Generally for piping whose nominal diameter is NPS 2 or smaller?

Threaded piping is commonly used in low-cost, noncritical applications such as domestic water, fire protection, and industrial cooling water systems.Threaded fittings are normally made of cast grey or malleable iron, cast brass or bronze or forged alloy and carbon steel.


Different sorts of fittings can be strung or attachment welded. It has various types of fittings like Threaded Pipe Fittings, Threaded Tee, Threaded Reducer, Threaded End Cap, Threaded Union, Threaded Coupling, and Threaded Cross & Threaded Outlet.


Advantages and Disadvantages of Threaded Fittings


Installation productivity is moderately high, and specialized installation skill requirements are not extensive.Leakage integrity is good for low-pressure, low-temperature installations where vibration is not encountered.



Rapid temperature changes may lead to leaks due to differential thermal expansion between the pipe and fittings.Vibration can result in fatigue failures of screwed pipe joints due to the high-stress intensification effects caused by the sharp notches at the base of the threads.In hazardous piping systems threaded connections should be avoided, if possible. Their vulnerability to fatigue damage is significant, especially where exposed threads are subject to corrosion.


Conclusion –

In this article, I have tried to explain detail information on the pipe. And also about their different fitting methods.