Renttech’s Johan Bester, talks about gasless flux-cored welding and the advantages of using the company’s UniArc Mag200 MC multi-process inverter.
When undertaking MIG/MAG welding outside, such as on a construction site or farm, exposing the weld to the weather may hamper progress and compromise the quality of the final result. Effects of wind or even just a breeze during the welding process can be a serious problem. Put simply, valuable shielding gas can all too easily get blown away: resulting in porosity, excessive spatter and inferior weld quality.
A simple solution is to use the gasless flux-cored welding process with a Lincoln Innershield wire, a process that was originally designed to replace stick or shielded metal arc welding (SMAW). As the name suggests, Innershield wires produce their own shielding gas to protect the weld from the atmosphere. This process is perfectly suited for outdoor use – particularly in extreme operating conditions in industries such as agriculture, construction, shipbuilding, mining or wherever maintenance is required.
“Changing to gasless wires brings many benefits, especially in areas where wind can be a problem – they eliminate the inconvenience and expense of shielding gases being blown away, as is often the case with traditional MIG welding. In addition, they make it easy to weld out of position, including vertical up, vertical down, overhead and horizontally. Gasless wires are also easy to use on both thin and thick gauge material – and they can fill gaps effectively, without burning through the plate or tubing. Welders who weld 1.6 mm tubing using stick electrodes will know a lot about this particular problem,” says Johan Bester, welding sales manager at Renttech South Africa.
“In the case of gasless flux cored welding, the filler metal for the weld is basically an arc-welding electrode turned inside out,” Bester explains. “The mild steel tube or sheath becomes the main filler metal to the arc and the flux inside becomes a light slag deposited on top of the weld.” He adds that the flux shapes the weld, while protecting it against the atmosphere throughout the solidification period. It also aids in removing impurities in the base material.
The resulting slag keeps the weld from sagging or falling out when welding out of position; and is easily removed with a steel brush or chipping hammer after the weld has solidified.
“Gasless wires are also known for being able to weld over painted, rusted or galvanised surfaces – making this a favourable welding process for maintenance, repairs or modifications on ‘used steel’.” Bester emphasises, however, that good welding practice should always include removing as much of the coating, dirt or rust as possible.
“Our UniArc Mag200 MC is a multi-process inverter that is especially versatile, offering not only gasless flux-core welding but it is also able to be used for MIG/MAG welding, stick and TIG welding,” says Bester. “This single phase 200 A, 230 V machine can take either a 5.0 kg or 15 kg wire spool and weighs only 22 kg.”
“If customers already have MIG/MAG/CO2 machines that can change polarity, they can easily convert to Innershield wires,” he adds. “All that is needed the correct drive rolls, a gasless welding torch and a spool of Innershield wire, and machine is good to go.”
“The Uniarc Mag200MC is a great tool to own,” adds Bester. “Combine this with the Lincoln Innershield wire and it is now much easier to produce quality welds.”
Renttech South Africa specialises in the rental and sales of a wide range of industrial equipment and has the largest fleet of rental welding equipment in the country. Its UniArc welding machines range from single phase 220 V machines to 380 V/525 V three-phase machines, and are generator-compatible if access to electricity is a problem.
“We are extremely pleased to bring such a handy, multi-purpose machine such as the UniArc Mag200MC to our customers working in industry, construction and agriculture. It offers new levels of convenience for the user, especially in a windy, outdoor context.
This machine is now available at all our branches with our technical staff ready to introduce customers to the world of flux cored gasless welding” adds Gerrit van Zyl, managing director of Renttech South Africa.