Trailing shields protect from bad welds

When using purge gas, normally argon, to protect welds from oxidisation, hot metal behind the torch is often ignored and this can lead to bad welds: trailing shields will prevent this problem

When using purge gas, normally argon, to protect welds from oxidisation, the area of hot metal behind the torch is often ignored and this can lead to bad welds, often seen on larger pipes and thicker materials where the volume of hot metal means cooling takes place after the torch has passed.

To overcome this problem, Huntingdon Fusion Techniques (HFT) manufactures a range of Trailing Shields under the Argweld brand that cover the area behind the torch with purge gas, preventing unwanted chemical reactions and helping to cool the weld pool.

A number of problems can result from too much oxygen reaching welded metal before it has cooled adequately.

These include oxidation, coking, discolouration and porosity.

The practice of "pickling" to remove unwanted colour and surface chemicals only removes impurities on the surface, it does not stop pockets of unwanted material from forming or weld failure.

HFT produce lightweight trailing shields (sometimes called trailing or leading shoes) to fit almost any radius of pipe or tube, internal and external, so that the torch can be used normally to trace around the circumference, as well as straight shields for plate or sheet work.

All Argweld Trailing Shields are made from extruded alloy casing with heat resistant, low friction silicon skirts to fit either side of the weld, creating a chamber along the length of the weld itself.

A specially designed mesh inside the shield ensures excellent gas distribution.

The shields come complete with an adjustable ring to hold the torch in place and actually help in guiding the torch for a straight weld.

Protecting the hot weld from oxygen through purging is vital when welding stainless steel, titanium or a range of other metals, particularly in the food and drinks and pharmaceutical industries, or in any safety-critical application such as the motor sport industry.

The cost of an Argweld Trailing Shield can often be justified by the saving from just one bad weld.

Huntingdon Fusion Techniques has a comprehensive distributor and after sales network in the UK and throughout the world.

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