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The Orbital Welding Process

Orbital Welding

Orbital welding is a process that was invented over fifty years ago.  It is a specialized area of welding where the welding arc is mechanically rotated around a static work piece continuously.  This welding technique is used on items that would be very difficult to weld manually, such as pipes.  This is an ideal welding technique for use on items where a strong weld is hard to achieve due to welding positions and size.

The process of orbital welding allows the welder to have complete control of the weld pool by achieving a perfect balance between gravitational force and surface tension.  Because orbital welding is mechanized, that perfect balance can be achieved without putting the welder in danger or creating faulty welds.  While a welder is needed to monitor the welding process, they are not required to perform the welds manually.  The process of orbital welding requires that the welding parameters be programmed prior to beginning the welding process.  Once the welding parameters have been programmed, the computer will initiate the welding process.  This involves rotating the piece to be welded, and insuring that the appropriate areas are being worked on.

Orbital welding uses the Tungsten Inert Gas technique of welding.  This technique uses non-consumable electrodes.  A cold wire feed can also be used when required.  The process of orbital welding allows for many different types of metals to be welded.  These include high-temperature, high-strength, unalloyed or low-alloyed carbon steels, nickel alloy, titanium, copper, aluminum and corrosion resistant steels.  Because orbital welding is conducted in an inert atmosphere, the controlled process produces welds that are very clean, have a low particle count, and are free from spatter. 

Because of the precise welds that can be created using orbital TIG welding, the smallest size standard tube can be welded.  On the other end, larger pipes with diameters up to 170mm with walls up to 3.5mm thick can also be welded with the use of closed chamber weld heads.  These specialized weld heads allow for the welding torch to be positioned precisely and insure that the pipe is securely held in place while the welding process is performed.  The inert gas atmosphere found in the closed chamber prevents the heat from tinting.  During the welding process a flexible hose system is responsible for supplying the welding head with power, inert gas, cooling water and filler wire when required. 

Filler wire is only required when the welding process is being used to weld thicker tube walls and hard to control materials that require the use of filler wire.  To insure that high quality weld seams are being produced, it is important that the tube ends are carefully prepared.  This requires that the edges of the pieces being joined be free of scale and impurities.  When thinner walled tubes are being used, this cleaning process can usually be achieved by performing a simple right-angled saw cut.  The pieces that have thicker walls require more attention be paid to the cleaning process — in most cases using a U-groove cross section is usually sufficient.

As further advancements are made in the field of orbital welding, MIG, MAG and FCAW welding techniques may soon be able to be used.  The addition of these welding processes will allow for a wider range of materials that can be welded using orbital welding.  Because of the high quality of the welds that are created using orbital welding, this is a technique that is in high demand.  Orbital welding has become a staple where clean welds are needed on materials that normally would be difficult to work on.  Being able to work on such a large scale has helped orbital welding become more popular and productive.

Ed C.


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