In the fall of 2001 the new headquarters of the ING bank on the west-side of the South at Office Park "Zuiderhof" in Amsterdam will be commissioned. The building absolutely attracts attention. Oostingh Staalbouw supplied a big part of the main steel structure.
Ing. Fred Neessen, EWE and Mieke Hendriks, Lincoln Smitweld BV, Nijmegen, The Netherlands
About Oostingh Staalbouw
Oostingh is very familiar with big projects. The company, founded in 1950 in "Katwijk aan Zee", the Netherlands, is widely known all over Europe. They supplied steel structures for the city hall in The Hague, the headquarters of Renault Holland and the Holland Casino's in Amsterdam and Zandvoort. Oostingh Staalbouw uses the latest developments which enables them to complete the full production process of steel construction from design to erection by their own staff. All this activities are guaranteed by a certified quality system, according ISO 9001. The VCA** certificate (according EN 45013) proves that safety and environment are given a lot of attention as well.
For one person it is a modern design, for another it is a futuristic design, but they both agree upon one thing: it is an absolutely striking structure, figure 1. The 8-story office building will be supported by steel "legs" of 12 meter high and will take up an area of 3000 square meters. A total of 4500-tons of S355J0 steel will be incorporated. The building is made up out of steel and glass, the presence of concrete has been restricted.
Oostingh Staalbouw is responsible for a big part of the bearing bottom of the structure as well as the reverse side of the building.
Selection type of welding consumables
Oostingh Staalbouw has chosen Outershield® products of Lincoln Smitweld. As always so, also for Oostingh Staalbouw, the golden 80-20 rule applies. This means that about 80% is fillet welding and 20% is butt welding. When it comes to welding positions, 70% will be welded downhand and 30% out of position. It is almost obvious that the welding consumables Outershield MC 710-H and Outershield 71E-H, both in 1,2 mm diameter were selected.
In the structure, steel plates are used with plate thickness from 20 up to 100 mm. The applicable standard is EN 10025, which requires a minimal yield strength of 345 MPa for the material thickness range > 16 and < 40mm. Table 1 gives an overview of the relation between the nominal plate thickness in mm and the required yield strength. The minimal required Charpy V- notch impact value is 27 joule at 0°C. The applied consumables do not only have to comply with this standard. The weld metal of the as mentioned cored wires should also comply with the American AWS-classification A5.18 and A5.20 respectively. Also the European classification according EN 758 is highly significant.
Outershield MC 710-H
The Outershield MC 710-H is, an unalloyed metal cored wire. MC in the name signifies Metal Cored, which implies a fill of only metal powder without any slag forming minerals. A metal cored wire provides the highest output by welding in downhand position (1G / PA) and in the horizontal-vertical position, (2F / PB) fillet welding, and (2G / PC).
A high output and efficiency will then only be obtained when welded with high current density. That means high current and high wire feed speed. In detail the characteristic properties of the Outershield MC710-H are as follow:
High deposition rate.
High efficiency (>95%) at optimal welding parameter settings.
Nearly no spatter
Less sensitive for porosity and lack of fusion compared to the solid wire
Deep penetration, see figure 5
High mechanical properties
The Outershield 71E-H is a rutile flux cored wire with fast freezing slag. Shielding gas Argon + (10-25%) CO2 (M2.1 according EN 439). That means this wire is extremely suitable for welding in the vertical up position. One can weld with a current setting of 250-260 A., even in the vertical up welding position. So a high deposition rate is possible. Of course this is depending on the plate thickness and joint configuration. Only with one current setting, the welder can apply the wire in most welding positions. As mentioned before, 80% of all the welding activities carried out by Oostingh Staalbouw consists of fillet welding, 30% has to be welded in position. A cross section of a fillet weld in vertical up position is given in figure 6a and 6b.
Outershield 71E-H meets the highest requirements of productivity. In short the qualities of the Outershield 71E-H are as follows:
- Large setting range for wire feed speed
- Good weldpool control
- Low spatter
- Easy slag release
- High mechanical properties
Nowadays the statement "Working with high productivity" is in the minds of a lot of companies. But what does productivity in fact mean in the world of welding ? Is welding at high speed the target ? Or is fast welding compared with the lowest possible costs the goal. That means not only high speed welding, but also welding with good results in one time without rejection and no repair. One could translate this into "welding consumables with excellent weldability, good wettability and X ray quality".
Outershield MC 710-H as well as Outershield 71E-H meet this description. Wires with very good weldability, but also weldable with high currents. The current per unit area of the wire tube cross section gives a high current density. The higher the current density, the higher the melting off or deposition rate (figure 7) and the job is ready in short time.
The question is: what packaging is the best for the job. Is the small 5 kg spool or the bigger 15 kg wire spool the best choice. Or even for the 200 kg AccuTrak® ? Within Oostingh Staalbouw people realize that changing the wire spool costs at least a 15 minutes break. In that time the arc is not burning and there is no wire melting off. The duty cycle is decreasing. With that in mind, Oostingh Staalbouw has decided to use Lincoln Smitweld flux cored wires only in AccuTrak® packaging for their shops. More information about AccuTrack packaging can be found in the brochures "AccuTrak®", numbers E09/00-L7 and "LNM 26", C4.30 07/00
Lincoln Smitweld is Mr. Marc Dofferhoff and the management of Oostingh Staalbouw B.V. in Katwijk aan Zee very grateful for their cooperation with the preparation and their approval to publish this company report.