Seamless tubing, particularly stainless steel seamless tube, is used in a variety of applications. From solar dishes to hydraulic lines, seamless coils tube is a critical component of many products. Here are four things that you may not know about seamless, stainless steel tubing:

1. How seamless is made

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One of the ways seamless tubing is created is through extrusion. Extrusion is a process in which metal or other material is forced through a die to create desired shapes. This process begins with a piece of conditioned steel of a selected grade. The tubes are extruded from a billet, then redrawn using a die. The seamless tube is heat-treated in a vacuum furnace and worked, cleaned, and re-worked until it’s been reduced to the ideal size. Seamless coil tubing can be reduced so far down that the inner diameter is the same size as a strand of human hair.

2. The difference between welded, welded-and-drawn, and seamless tube

Selecting welded, welded-and-drawn, or seamless tubing for an application is a complex process. Seamless Tubing offers increased corrosion resistance because it is 100% seam-free, without any longitudinal or orbital welds. Longitudinal welds present an opportunity for defect, which cannot be tolerated in critical applications. To produce a welded tube, flat strip is roll-formed and joined with a longitudinal seam. The process can be done with laser alignment or tig welding. The weld area is dimensionally inconsistent with the strip and causes areas of stress concentration, particularly for tubes that are subjected to a high internal pressure. Furthermore, these crevices, which exist on both sides of the weld seam, create opportunities for corrosion and metallurgical contamination during heat treatment can lead to corrosion as residue becomes trapped. These crevices can cause cracks, which can propagate and cause the welded tube to rupture.Some manufacturers use different methods in an attempt to minimize the dimensional variation and integrate the weld seam including roll, sink, or float and plug drawn. These products are known by many names including: welded-and-drawn, seam-free and seam-integrated. Redrawing as-welded tubing with a die and plug and subsequently annealing helps homogenize the weld. In order to fully homogenize the weld, these operations need to be repeated several times, increasing the overall cost. Seamless tubing, in comparison, has zero welds.

3. Popular applications for coiled tubing

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Seamless stainless steel coil tubing reduces the risk of impurities, increases corrosion resistance and reduces installation costs in many applications, making it a preferred choice for extreme environments. In the Oil & Gas industry, seamless tubing is used primarily for control lines, chemical injection, and sub-sea safety valves. The Chemical Process and Instrumentation industry also has popular applications for seamless tubing including: Steam & heat trace bundles, flow measurement & sensing and fluid & gas transfer. Small diameter tubing is a trusted choice for gas chromatography (GC) and high-performance liquid chromatography (HPLC) equipment, because manufacturers now require smaller samples to be processed at higher speeds. Seamless stainless steel capillary tubing is used to plumb many of these high-precision systems.

 Newer applications for seamless coil tubing include compressed natural gas transfer for vehicle refueling and hydrogen transfer for material handling applications. In these applications, seamless saves time and labor because multiple fittings are not needed. Seamless coil tubing is also used in other industries such as Aerospace & Defense, Alternative Energy, Shipbuilding, and Health Care. 

4. Seamless coil is available in different forms & lengths

Did you know the longest seamless coil in the world can stretch 6,926 feet? This is approximately 5.5 times the height of the Empire State building in New York, NY. Seamless tubing is available in a number of high-performance, corrosion-resistant alloys and sizes ideal for ultra-high purity, military, aircraft, semiconductor, medical and general instrumentation applications. It is available in coil or straight form depending on your needs and application.

– To learn more about Seamless Coil Tubing visit our products page.