Dramatic savings can be achieved when welding stainless and chromium steels and also titanium alloy tube and pipes with the use of an Inflatable Pipe Purging System.
By restricting weld purging zones, Inflatable Pipe Purging Systems achieve a huge saving in time waiting for pipes to be completely filled with argon, purged down to a low enough oxygen level to start welding safely and also the cost of using a large amount of inert gas.
To avoid such risks and to see that the inert gas being delivered to the pipe purging system is controlled, Huntingdon Fusion Techniques HFT® have designed and developed PurgeGate®, a unique valve which regulates the pressure and flow of gas that is passed through the system, ensuring that it will not burst regardless of the pressure and flow rate.
Measuring the oxygen level during Pipe Purging is crucial. Stainless steel has to be monitored down to at least 100 ppm, however alloys such as titanium and zirconium may need to be monitored down to as low as 10 ppm.
Pipe Purging Experts Huntingdon Fusion Techniques HFT®’s PurgEye® 200 Weld Purge Monitor® will ensure zero colour, non-oxidised welds are achieved every time, with accurate readings down to 10 ppm.
The PurgEye® 200 is a portable, hand held monitor, specifically developed and designed for use when welding titanium, zirconium, high specification stainless steel and nickel alloy joints, so that the user can produce metallurgically sound and oxide-free welds every time.
Weld Purging is the act of removing oxygen from the vicinity of a joint before, during and after welding. Metals that require weld purging include stainless steels, titanium and zirconium.
Weld Purging various sizes of tubes and pipes can be challenging as well as expensive, which is why many welders today continue to construct their own dams to cut costs. Homemade dams made from material such as foam, sponge or paper can often lead to loss of welds when they leak or slip from position thus flooding the welding zone with air.
Leaders in Weld Purging Technology, Huntingdon Fusion Techniques HFT® offer low cost Weld Purge Film® Kits which can be cut to each pipe size.
The Welding Institute states that “Titanium is a reactive metal; it will burn in pure oxygen at 600°C and in nitrogen at around 800°C. Oxygen and nitrogen will also diffuse into titanium at temperatures above 400°C raising the tensile strength but embrittling the metal. Despite this reactivity titanium is used extensively in chemical processing, offshore and aerospace applications."
In critical welding applications, it is therefore crucial that the oxygen level surrounding the weld is purged of oxygen to 50 ppm or lower. Measuring the oxygen level is the most efficient way to know exactly when to commence welding.
The PurgEye® Desk is leading the way in inert gas purging technology by reading oxygen levels from 1,000 ppm, right down to levels as low as 1ppm (highly accurate to 10 ppm), ensuring titanium welders achieve perfect oxide free, zero colour welds time and time again.
Avoiding the requirement to drain down pipelines for repair work or to carry out maintenance can save a considerable amount of time and potential loss of product.
Qwik-Freezer™ Pipe Freezing System eliminates the need to drain pipework by creating a freeze plug. Available from the Pipestoppers® Division of Huntingdon Fusion Techniques HFT® Qwik-Freezer is a very cost effective and quick way to perform pipeline maintenance without draining the system, meaning very little or no system downtime.
Luke Keane, Technical Sales Manager for HFT® said: “Qwik-Freezer™ is a simple, low cost method for pipe repairs. A flexible jacket is wrapped around the pipe at the point where the freeze is required. A nozzle in the jacket is then coupled to a cylinder of low cost liquid carbon dioxide by means of a high-pressure hose. When the CO2 is injected into the space between the jacket and the pipe, at a temperature of -78oC, the pipe contents freeze and a secure ‘ice plug’ is formed, which seals the pipe.”
Metals that are classed as reactive are sensitive to oxygen when they are heated, therefore the oxygen must be purged from the welding zone before, during and after welding. When welding reactive metals such as titanium, zirconium and nickel alloys, it is therefore important to monitor the oxygen level before, during and after welding.
Weld Purging Experts Huntingdon Fusion Techniques HFT® have designed and manufactured the PurgEye® 600, all in one Weld Purge monitor®, which reads from atmospheric level of oxygen (20.94%), down to one part per million (0.0001%).
Weld Purging with a minimal level of oxygen present will avoid discolouration of the weld and heat affected zone and limit oxidation that could lead to a loss of metals’ corrosion resistant properties. It will help to guarantee the greatest weld joint strengths and the highest resistance to corrosion.
Heavy-duty pipe blocking and stopping is easy with the Steel Plugs Range from Pipestoppers®.
Pipestoppers®, a division of Huntingdon Fusion Techniques HFT®, manufacture Steel Plugs, which have been the favoured heavy-duty plug for applications such as leak testing, pipe stopping and blocking for their sealing effectiveness and durability.
HFT Pipestoppers® Steel Plugs can be used for low pressure testing and plugging all pipes, pipelines and pipe work between 2 to 48” (50 to 1,200 mm) diameter.
Luke Keane, Technical Sales Manager for HFT® said: “Plugging challenges are a thing of the past with our Steel Plugs range. They provide a strong, leak-free seal with each plug having a long life span.”
Correctly preparing each Tungsten Electrode for welding is crucial. It is one of the most important variables in TIG / GTA welding and each Tungsten Electrode must be ground properly to improve arc starting, stability and subsequently weld quality.
Manufactured with a diamond wheel, the TEG-1000 Tungsten Electrode Grinder from Huntingdon Fusion Techniques HFT® will ensure the grinding of each Tungsten Electrode results in clean and smooth finishes, with no splintering and eliminating arc jumping.
Luke Keane, Technical Sales Manager for HFT® said: “It is very important to have a dedicated Grinder for Tungsten Electrodes. This will help to ensure that the wheel and tungsten tip do not become contaminated during the grinding, which can possibly transfer foreign material to the weld.”
Weld Purging short pipe pieces and dome-end welds where tandem Inflatable Tube and Pipe Purging Systems are unsuitable, Huntingdon Fusion Techniques HFT® manufactures Weld Purge Dams.
Ron Sewell, Chairman for HFT® said: “When welding tubes and pipes, the most cost- effective solution is to restrict the volume, usually with a Tandem Weld Purging System, especially welding metals such as stainless steels, titanium and zirconium.”
“Where Tandem Weld Purging Systems are unsuitable, Weld Purge Dams are available for pipe diameters from 6 to 88” (152 mm up to 2,235 mm) and offer a low-cost alternative to foam or cardboard dams that are still frequently handmade by welders on site. Unsuitable materials can often lead to rework of some kind and in worst cases cause welds to be rejected.
Supporting the liquid weld root with a high temperature Backing Tape will ensure minimal oxidation and will require much less post-weld cleaning.
Argweld® glass fibre Weld Backing Tape® from Huntingdon Fusion Techniques HFT® supports weld roots and eliminates the creation of slag, whilst removing contact with air to dramatically reduce the amount of contamination.
Ron Sewell, Chairman for HFT® said: “Available up to 600 amps, our Weld Backing Tape® has no true melting point so it works satisfactorily with TIG or MIG welding (GTAW or GMAW) where temperatures can reach up to 6,000ºC. This overcomes the concerns associated with ceramic fibre versions that have a melting point of 1,800ºC.”