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How do we ensure that every sheet of Valast® 450 supplied to our customers has superior surface quality and consistent flatness?
Half of the answer is Tata Steel’s hot strip mill in IJmuiden, but for the other half we have to look to the downstream decoiling facilities.
The way in which we produce Valast® 450, using our hot strip mill in IJmuiden, will naturally lead to a superior surface quality and consistent flatness compared to many abrasion resistant (AR) products that come from a reverse plate mill. (For a detailed explanation of this, see our article on the differences between AR strip and plate.)
However, when dealing with any type of steel production there are a few further challenges that must be overcome.
The first such challenge is oxidation. It is very common for a thin layer of oxides to quickly appear on the surface of any untreated steel, which can be removed by the customer. However, Valast 450 has been engineered to demonstrate superior surface quality, meaning less treatment by our customers before processing. We didn’t want all that hard work undone by providing the steel with an oxide layer.
Second, we faced a challenge common to any strip steel. Once the strip is rolled into a coil, it effectively becomes a very large and powerful spring (see more on how we contain the coiled spring in this article). When the steel is decoiled and cut into sheets, they still retain some of the elasticity of the coil, and so aren’t perfectly flat.
To solve both of these challenges, we needed to look at the decoiling process, which takes us to our two European decoiling facilities, one in the Netherlands (Maastricht) and one in the UK (Llanwern)
These two sites feature two of the world’s most powerful decoilers, as a response to our expansion into thicker and stronger grades of steel. The ways in which the decoilers solve our challenges are beautiful in their simplicity.
First, the decoilers are fitted with brushes, which scrub the steel immediately before and after it is decoiled. This removes the oxide layer from the surface of the steel, revealing the superior surface of the strip. As it is decoiled, the strip is cut into sheets of bespoke dimensions according to the customer’s order. The sheets are carefully stored to stop further oxides forming on the surface, ensuring Valast 450 is delivered to the customer in perfect condition.
The second challenge requires a more high-tech approach. As the steel passes through the decoiler, its mechanical properties are measured. This allows the decoiler to understand the amount of force that needs to be exerted on the steel to stop it from curving. It immediately applies this force to the strip, and the result is a consistently flat sheet of Valast 450.
So, there you have it – the key to delivering Valast 450 in consistently flat sheets with superior surface quality is as much due to our decoilers in the UK and the Netherlands as it is the hot strip mill.
Want to find out more about Valast 450’s superior surface quality? Take a look at our article, Valast 450: Beauty that doesn’t fade.