TPT November 2012

Blasting and coating

Duratrim solves welding problems A COMMON problem in the HF welding process for coated materials is the inclusion of oxides in the weld zone: this can cause premature weld failure and quality control rejects. This can lead to huge costs in scrap and ultimately loss of reputation with the end customer. Duratrim is a new edge conditioning system specifically designed to solve the problem with aluminised and galvanised tubular products. savings; increased production ‘uptime’; higher weld integrity; increased life from ID/OD scarfing tools; and increased life from impedors.

The unit is positioned at the entry end of the mill between the accumulator exit and mill forming bed. The strip is then simply fed through the Duratrim and the insert tool holders adjusted prior to starting. After starting no further adjustment is normally required and standard cross welds will comfortably pass through without disruption to production. Duratrim can also be used offline for edge treatment in a ‘coil to coil’ process; typically this would be for TIG mills where one unit is utilised for multiple process lines. While Duratrim is particularly effective for aluminised and galvanised strip it can also be used for regular steel as well as non-ferrous materials such as stainless, brass and aluminium. Superior Technologies Europe – UK Website: www.st-europe.co.uk

It works by removing a very small amount of material from the top, bottom and sides of the strip prior to entry into the forming mill. The unique design differs from other edge preparation systems as Duratrim allows the strip to ‘float’ through the unit rather than ‘forcing’ it through scarfing inserts (like other systems). This is made possible by four pairs of carbide scarfing inserts mounted in specially designed tool holders. The tool holders operate with continuous positive pressure on the strip moving in both vertical and horizontal directions, thus ensuring small variations

Reducing problems with welding

in strip profile, width and thickness are taken care of automatically. The system requires only compressed air to operate and has individual pressure adjustment of all eight scarfing inserts making it possible to individually adjust the amount of material removed. Insert and tool holder design give an edge profile at the welding point which can reduce the inside and outside welding bead. Less ‘squeeze’ out is required leading to significant benefits including: reduction of strip width offering material

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N ovember 2012