We have two rolling mills – one at Dillingen in Germany and one at Dunkirk (Dunkerque) in France. We deliberately sited the warehouse on one of the largest canals in the Netherlands so the steel plates are delivered to us by barge. The barges carry about 2000 metric tonnes of steel plates each and we usually have a few deliveries each week.
The plates come in and are offloaded by crane from the barge. We do a visual inspection immediately and where required, we conduct more detailed testing if it looks like there is a flatness problem. Rejected plates are sent back to the mill on the next barge. The plates are then tagged and moved to the right stack.
When you store steel plates, you need a very strong foundation as a cubic metre of steel weighs about 8 tonnes. Stack them too high and the foundations will start cracking. That’s one of the reasons that we have wooden mockups of our plates at exhibitions. Exhibition centres aren’t designed to take this load!
I think we have about five thousand plates at any one time. These are normally stacked by grade, by dimension and thickness. As we know where any particular plate is at a time, there is some complex mathematics that goes on behind the scenes to help minimise the number of plates that we have to lift to get to any particular plate. You can think about it in the same way as waiting for an elevator in a tall office building. If the lifts always remain where the last person got off, you have a pretty inefficient arrangement and the average waiting time will be longer. However, if you have 3 lifts, you programme them so one waits near the top, one waits in the middle, and one waits near the bottom.
We arrange the plates in a similar way so that the average time to pick up a plate is minimised. There’s a lot more to it than that of course, but it is one of the reasons why we can deliver plates to Antwerp very quickly if you have an urgent requirement.
Another important fact is worth mentioning is that all of our plates are kept inside. We have two warehouses on site (about 20,000 m2) and these keep the plates dry and mostly rust free (some oxidation occurs but this and the mill scale can be easily removed during fabrication).
We have a couple of 25 MT Scheffer cranes with smaller additional cranes to handle profiling. We don’t use any forklifts for plate movement (except when palletised) as this can damage the plates unnecessarily.
Loading takes place within the warehouse and this keeps the plates dry and the process safer – though still cold on occasion as the warehouse is unheated.
I hope that this has given you a bit of insight into how we handle our steel plates. If you have any questions, please do ask them in the comments below.