TPT May 2008

T ube & P ipe W elding: T rends & P rogress

High-speed pulsing capability with new 350 DC TIG welder

Miller Electric Mfg Co, USA, has introduced the new Maxstar ® 350 DC TIG/Stick inverter to improve DC TIG welding productivity and quality in industrial applications. Compared to the previous model, the Maxstar 350 TIG welder offers high-speed pulsing capabilities – now up to 5,000 pulses per second, which is a ten-fold improvement. It also offers 50 amps more welding power and is more robust. The Maxstar 350 delivers 5-350 amp output (300 A at 32 V, 60 per cent duty cycle), weighs 135.5lb and features Auto-Line technology, allowing it to run from any input power, 208 to 575 V, single- or three-phase. A single, full-featured Maxstar 350 model has replaced three previous models. An easier-to-understand front panel controls basic TIG welding functions, while a secondary menu controls additional setup parameters and values. The Maxstar 350 is available as a stand- alone unit, as a TIGRunner package

featuring the Coolmate 3.5 cooler and a TIGRunner package with cooler and Weldcraft water-cooled torch. The Maxstar 350 enables users to adjust the number of pulses per second (PPS) from 0.1 to 5,000 PPS. It also enables control of the amount of time each pulse cycle spends at peak amperage from 5 to 95 per cent of total cycle time. Users can set the background or ‘low’ current pulsing value to between 5 to 99 per cent of peak amperage. Pulsing in excess of 40 PPS increases weld puddle agitation to create a better- as-welded microstructure. Pulsing the weld current at 100 to 500 PPS also constricts and focuses the arc. This maximizes arc stability, increases penetration and increases travel speeds. Pulsed welding also lowers heat input and reduces the size of the heat-affected zone (HAZ). Typical applications include stainless steel, nickel alloys and other metals where excess heat can lead to warping or

degrading metallurgical composition (eg carbide precipitation). In automation applications, which require maximum travel speeds, pulsing at frequencies beyond 500 PPS can further enhance arc stability and concentration. Miller Electric Manufacturing Co – USA Fax : +1 877 327 8132  The new Maxstar  350 DC TIG/Stick inverter offers high speed pulsing capabilities (up to 5,000 pulses per second)

Email : info@millerwelds.com Website : www.millerwelds.com

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M ay 2008

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