Seamless pipes

These are pipes that are made without a welded seam. They are manufactured through a hot-forming process using an extrusion which is then followed by cold-sizing to produce the desired dimensions, shape and properties.

Benefits of seamless pipes

Seamless steel pipes have the ability to withstand high pressure. This is because they are not welded, thus they are equally strong all around their circumference. Welded pipes have a weak point which is the welded seam.

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They are uniform in shape. They are round in shape unlike welded seams pipes which is wrapped around one another and then it is welded. Welding includes heat, stress and other variables in the process thus uniformity cannot be achieved.

Strength is also an advantage of the seamless pipes. A pipe should support its own weight and also when it is filled with material, it should also manage to support that weight. Pipe leaks usually occur in welded pipes at the welded seams. Since seamless pipes are not welded, they are not subject to these leaks and failures. Strength also makes them reliable in harsh weather conditions.

These benefits makes them more expensive and more reliable. They are often preferred in commercial applications such as:

Fluid Transport

Seamless steel tubes are mostly used in oil and natural gas transmission over long distances, water transport, this is either the sewerage system or a water diversion system. This is because they are not prone to leaks or pipe failures.

Mechanical and Automobile

In cylinders, bearings and other hollow parts especially in cars, seamless steel tubes are used. These tubes can be manipulated to form different shapes and designs. They are sometimes referred to the backbone of car rear axle tubes. They are important for manufacture of the precise parts. These include the ASTM 511, A513 and A554 among others.

Aircraft Tubing.

Seamless pipes are important in aircraft structural tubing. In some cases the nickel and chromium stainless steel pipes are used due to their non-corrosive nature. These pipes are always manufactured with specifications from Aerospace Material Specifications or sometimes from Military Specifications. Aircraft hydraulic systems also require these stainless steel pipes because of their non-corrosive, ductile and high-strength features.

High Temperature and Pressure Applications.

In this application, seamless pipes can be used in heat exchanger tubes and condensers. These two processes are involve heating and cooling of fluids. It is also applied in boiler tubes which involve high temperatures and pressure. ASTM A199 is an example of tubes which a desirable to this particular application.

However stainless steel pies and tubes are normally hard to classify. Most are distinguished by the function. Stainless steel is also classified by grade and type. In most cases type 304 is used as it is highly chemical and corrosion resistant. However, for applications with temperatures between 800 and 1640 F, type 304L is preferred due to its high carbon limit. Type 304 is however not used because it is prone to carbide precipitation. Other types of steel normally contain additives like nickel, which strengthen them for particular applications.