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In Tubes, Pipes and Vessels
The oil, gas, water, food and drinks, aerospace, power generation, construction and pharmaceutical industries fabricate many thousands of metres of pipes every year and all joints need to be tested for leak tightness before release for use..
It is often difficult to meet requirements for quality using manual welding.
Orbital welding has become an essential process with many tube and pipe fabrications because modern equipment can be fully automatic and reliable and offers repeatable results.
Certain welding positions such as overhead and down-hand welds often lead to faulty welds because of restricted and uncomfortable operator access.
Advanced Training Courses
Safety Critical Welding
Welding skills and the introduction of new technologies are focus areas behind a series of recommendations set out in the "2012 Nuclear Construction Lessons Learned" study report.
The report, published by the Royal Academy of Engineering, notes the need for advanced training in some welding practices*.
Titanium and its alloys are highly reactive metals and welding requires the use of special techniques to avoid embrittlement by contamination with oxygen and, to a lesser extent, nitrogen from the atmosphere. Both gases are absorbed rapidly at temperatures prevailing in fusion welding. Gas shielding requirements are thus much more stringent than for most other materials. Complete protection for the weld pool, the underside of the joint and the region behind the weld metal as it cools is essential if successful welds are to be made.
Manufacturers involved in the biofuel, semiconductor, aerospace, food production and pharmaceutical industries are all concerned with handling under aseptic conditions. The presence of any debris and contamination in finished assemblies is unacceptable and quality control procedures must be rigidly adhered to.
Nickel and its alloys are used in a very wide range of applications - from high temperature oxidation and creep resistance service to aggressive corrosive environments and very low temperature cryogenic applications. The Nimonic and Monel alloys are the most common proprietary metals, but the total range is extensive, covering nickel contents from 30% to 99%.
Whilst most welders recognise the need for inert gas purging when making quality joints, it is not obvious why purging should be continued after the weld has been completed. The answer is obvious really; hot metal oxidises in the presence of air so the weld and any metal surrounding it will discolour until it has cooled. Welders know to keep the inert gas flowing from the torch to prevent oxidation around the surface. Why do they overlook the underside?
Why should you use Inert Gas Purging when welding Stainless Steel, Titanium and Nickel Alloys?
Preventing oxidation and thus avoiding discolouration and weld underbead discontinuities in tubes and pipes can be achieved readily by purging the inside with inert gas. This simple procedure saves both time and cost, both of which can be considerable. Consider the thoughts of one specialist;
Why should you use a Weld Purge Monitor?
Preventing oxidation and contamination of joints during fusion welding demands that special attention be given to local protection using an inert gas. Whilst the welding torch provides a protective cover to the top of the fusion zone, inert gas coverage is also required in the region of the weld root. If this is not done, the weld root and local metal will at best discolour but invariably will become heavily oxidised.
