The challenge:
There were two main sections at Hische which made significant use of welding technology: The welding primarily involved circumferential seams on pipe components for gas turbine power plants. The weld roots of the circumferential seams on the pipe components were welded using a TIG process. The company also welds long box profiles. To achieve reliable results when welding three-metre-long components with the MIG/MAG welding machines, a rail first had to be placed underneath every side of the box profile. This was the only way to prevent sagging of the seam and subsequent poor quality.
The solution:
coldArc, a modified short arc for MIG/MAG processes, was used by Hische to get the desired results from root welding that were previously only possible with TIG welding. Between TIG and MIG/MAG, however, MIG/MAG welding offers significantly higher welding speeds. The forceArc arc is targeted and concentrated. It is further characterised by deep penetration, good sidewall fusion and spatter-free welding. When welding box profiles, single-bevel groove seams can be welded with full penetration from one side and the backing run is automatically created on the rear side.
The success:
Welding the root pass with MIG/MAG and coldArc instead of TIG boosts the welding speed by 40% and with almost identical quality. When welding box profiles, Hische can use forceArc to avoid pre-assembly and having to tack weld the four rails. This saves a significant amount of material and time. With forceArc, the individual parts are tensioned and then welded with full penetration, saving two hours per crane boom, not to mention reductions in the amount of gas and welding consumable used. This is because the forceArc allows the welder to narrow the preparation angle of the weld seam, thereby cutting welding times, heat input and distortion. Thanks to the high weld seam quality of Hische’s newly-acquired welding processes, the company was able to access the new market of marine technology, an industry with extremely high requirements on product quality and safety.
