Welding technology of the future
Incredibly economical, extremely safe

Mündersbach, 23 January 2012. For over 20 years, renting out tower cranes has been the core business of Wilbert Kranservice GmbH, Stromberg, to the west of Bingen on the Rhine in Germany. Since 2003, Wilbert Turmkrane GmbH have successfully produced their own cranes – for sale too. In 2008 the company opened a new plant about three kilometres away in Waldlaubersheim (fig. 1). The programme of this medium-sized, family-run group of companies is rounded off by Wilbert Montage GmbH.
"Perfect welding", according to Günter Kronewitter, head of sales for Kranservice GmbH (fig. 2), "is the be-all and end-all for the high safety and quality of the red
Wilbert cranes.“ To improve profit margins, their production department is increasingly using the innovative metal active gas (MAG) process called forceArc^® from the technological leader EWM HIGHTEC WELDING – with astounding results.

Reaching any angle thanks to a large stick-out
Generally, in Waldlaubersheim welds were produced with active gases and solid wire according to EN ISO 4063, process 135. The materials used are S235 and S355 with thicknesses from 3 to 150 millimetres, M21 shielding gas (82 percent argon, 18 percent CO₂).
The advantages which this new variant of the MAG welding process brings to a company were pointed out by the manager of steel construction at Wilbert, Roland Bender (fig. 2): "We have a lot of diagonal struts to weld. That means we always have to weld the construction at quite a sharp angle, which is difficult to access or not at all accessible for the large nozzle of an MAG torch. The forceArc^® arc is however so powerful that it acts very precisely with great directional stability, even with the stick-out protruding by 40 millimetres. Our welders can guide it reliably and penetrate exactly to the root of the seam." (fig. 3)

Half the time, twice the service life, pass on pass...
Bender also explains the cost benefits of the process: "With forceArc^® we can reduce the included angle of weld seams from 50 to 30 degrees. This means we can halve the milling time required for weld preparation, the tool wear is also halved and the power consumption is reduced considerably. The number of filler passes required is significantly lower and we can weld pass on pass without the need for intermediate passes or finishing work. With the conventional MAG process, every intermediate pass had to be grinded, which reduced its volume by 50 percent, so we now achieve incredible savings on filler wire, grinding discs, electricity, shielding gas and working time. In addition, the Phoenix welds the intermediate and final passes with metal cored wire – as defined in process 136 in the EN ISO 4063 standard – which increases the deposition rate. For the root we continue to use solid wire. By now we also source both types of wire from EWM."

Focus on process reliability
After the Schweißtechnische Lehr- und Versuchsanstalt in Mannheim (weld training and research centre) had successfully carried out welding procedure tests for the new method, Wilbert switched to the forceArc^® joining process for even more of its crane constructions. Welding engineer Linck cites the following reasons: "One of the main arguments for the new process variant is its high reliability, which decisively improves the quality of our products. The root fusion is excellent; in most cases there is no need for the backing run normally required, which involves repositioning of the workpiece; the sidewall fusion is optimal and the penetration depth good; almost no pores are formed; and the welds are reliably X-ray proof." (fig. 5)

Clean work, high reliability and quality
The company is a certified manufacturer for welded steel constructions according to DIN 18800-7 (comprehensive qualification certificate). Production takes place in two shifts per working day. There are three specialist welders and twenty standard welders with qualifications to EN 287-1 ready to work in the welding shop. The team found it really easy to change to the high-tech joining process. It not only improves and simplifies their work, but is also much more environmentally friendly (fig. 6): the workplace is much cleaner, emissions of noise and fumes are much reduced and the entire process produces less heat. As the heat input is considerably reduced, thermal distortion of the components is minimised and there is less change in the structure of the parent metal. To guarantee the safety of the Wilbert tower cranes, the company puts a lot of effort into quality checks. Every welder labels their welds with their own stamp. As specified in the drawings, the welds are checked using ultrasound, magnetic powder, dye penetration or X-ray inspection.

All-round protection – unique across Europe
Quality is also taken very seriously in the other production steps at Waldlaubersheim. Wilbert tower cranes are unique in being powder-coated as standard. To be able to do this, the company operates the largest plant in the whole of Europe. It can process parts with a weight of up to 20 tonnes and maximum dimensions of 14 x 3.30 x 3 metres (fig. 7). For an extremely durable coating, the working steps are: shot peening, electrostatic powder coating and baking. This high-quality coating achieves a durability of 80 percent of the "coastal standard". Other steel construction companies are thus very happy to use Wilbert's services for their larger-sized components.
Compared to liquid paint, powder coating is much more durable. The processing times are also much shorter. Even years later, the colours still shine bright. The process is also very good for the environment as no emissions are produced such as odours or fine dust. In addition, the waste heat from the ovens is used to heat all the workshops and offices.

An eye on the future
At Wilbert, preliminary investigations are already under way for other welding innovations: Heat-reduced welding is being tested with the next EWM development, coldArc^® – on tubes whose ends are crushed or sheared off due to the inherent design. This means that higher tolerances are required in weld preparation. With the viscous weld pool produced by coldArc^® air gaps of up to one centimetre can be reliably bridged.

Figures:

Fig. 1: View over 120,000 square metres of storage and production facilities: Since 2008, Wilbert has been producing tower cranes with outstanding properties at its new Waldlaubersheim plant
Photo: EWM HIGHTEC WELDING


Fig. 2: The team for the successful introduction of innovative welding processes at Wilbert: From right to left – welding engineer Bruno Linck, then Roland Bender, manager of steel construction & welding engineer, Michael Weißschädel, general manager of Wilbert Montage GmbH, Günter Kronewitter, head of sale for Kranservice GmbH, EWM service partner Klaus Weiler
Photo: EWM HIGHTEC WELDING

Fig. 3: Diagonal struts – sharp angles in the design are often hard to reach for MAG torches. The exception: The powerful & directionally stable forceArc^® arc operates precisely even with a stick-out of 40 millimetres
Photo: EWM HIGHTEC WELDING

Fig. 4: Solid eye plates e.g. for a rotating frame: "…reduced included angle, incredible savings, halved working time…“
Photo: EWM HIGHTEC WELDING

Fig. 5: Successful welding procedure test: One of the main arguments for the forceArc^® process is its high reliability with optimal root and sidewall fusion and deep penetration; in addition, it is X-ray proof and there are almost no pores
Photo: EWM HIGHTEC WELDING

Fig. 6: The team found it easy to change to the high-tech joining process. It not only simplifies their work, but is also more environmentally friendly
Photo: EWM HIGHTEC WELDING

Fig. 7: Europe's largest powder coating plant is at Wilbert's in Waldlaubersheim. Other steel construction companies are very happy to use Wilbert's powder coating services for their larger-sized components.
Photo: EWM HIGHTEC WELDING

	Download PDF
	Download Word File
	Download Figures as Zip