When finalising your structural hollow section design, incorporating hot finished normalised S355NH steel tubes, do you then consider whether they’re going to be readily available?
At Tata Steel, we pride ourselves on supplying high quality steel tube products. When it comes to structural hollow sections, our hot-finished range to EN 10210 fits this bill perfectly. is widely recognised as the default for hollow sections across a broad range of construction and structural applications, and to make sure it remains there, we have worked hard to ensure the widespread availability of this range.
We manufacture over seventy thousand tonnes of hot finished hollow sections for the UK market every year - but very often for a particular project, individual lengths of different section sizes are required. So the UK market is well served by a smooth supply chain which is able to supply just the right sections, at the right time, in the right lengths and often with some initial fabrication such as cutting and drilling. We supply to all the major national stockholders, giving a full spread of availability throughout the UK.
We have the ability to produce over 650 different steel tube sizes in our range, across circular, square, rectangular and elliptical shapes, ranging from 40mm square up to 400mm square and equivalents in other shapes. However, some sizes are more popular than others and no stockholder would want to stock everything, so we have looked at our own production patterns to understand how well our range is represented in the market.
Dean Paterson, demand planner at Tata Steel explains “We manage our steel tube mills to be as efficient as possible, so we have specific rolling programmes, but these differ across our three mills that produce . We looked at how often any particular size has been manufactured and supplied into the UK market over a full year period. By expressing that as a proportion of the total number of times we could have manufactured that size, we were able to build up a picture of the repeatability of demand in the UK market right across our wide section size range.”
This exercise has enabled us to classify each section size relative to it’s availability. The sizes we produce most frequently are always likely to be available throughout the supply chain and stock is regularly replenished. This accounts for 93% of the volume of in the UK market, covering 176 section sizes from 40x40x3.2mm at the smallest all the way to 500x300x16mm at the largest and a good spread in between.
1 - In general, any size of classified as category 1 is likely to be held in stock by at least one of the leading stockholders in the UK.
2 - The second category is those section sizes which we manufacture on between 20% and 60% of available opportunities. These sizes are all manufactured several times per year, but sometimes without the regular re-stocking which we expect for category 1 sizes. This accounts for a further 6% of our production volume and 49 additional sizes. These sizes are likely to be in stock or available on a short lead-time.
3- The third category of section sizes are those which we manufacture only occasionally. Most of these sizes are intermediates which are rarely required, but our wide-ranging capabilities, regular rolling programme and good relationships throughout the UK structural steel supply chain ensure that even these sizes, when they are required, can be produced. Having knowledge about which sizes are likely to have a longer lead-time and minimum quantity requirements can help ensuring an efficient design and construction process.
Dave Chapman, technical advisory engineer for Tata Steel, explains the importance of this to engineers: “I talk to structural engineers all the time about specifying EN 10210 hot finished hollow sections and one of their biggest concerns is knowing whether their design will get changed later in the process because the section they have chosen isn’t available. This new classification, based on real-world data, really helps engineers to know what to specify.”
Dave also stated that this doesn’t limit engineers to using only the biggest runners: “The 176 section sizes which are most available are widely spread across the range of sizes and do cover most situations, but it’s also great to see the second classification – those that are produced regularly, but not quite as often. In reality, many of these will be in stock and if they’re not, they can quickly go onto a rolling cycle.”
For all the other sizes in the portfolio which are infrequently manufactured and not widely stocked, Dave is similarly optimistic: “Most of the third-category sizes are intermediates that engineers are less likely to use anyway. But by openly classifying them like this, an engineer can easily see that if they really want these sizes, they are available, but attention needs to be paid to getting them manufactured, since there will be lead time and minimum quantities to consider.”
As well as making availability tables available, we are now starting to build this classification of hollow sections into our information aimed at helping engineers to specify the right steelwork from the start. The industry-standard “Blue Book” will be updated to include this information, while there are further tools in development which we will make available to help engineers to design more efficiently.
To help make this availability classification clear, we have produced a handy guide to the availability of our range of true hot finished hollow sections below:
The range of true hot finished hollow sections represents by far the widest range of such steel tubes on the UK market. By specifying to EN 10210 S355NH, you can now not only be assured of the advantages of a fully normalized hollow section, but also have peace of mind in the best availability across the widest range of sizes.
A final word from Dave Chapman, “What really helps with engineers is that we’ve not just looked at how many tonnes we produce, but we’ve linked that to the real-world availability by looking at how often a particular size is supplied into the UK market. Of course we can’t guarantee what any of our customers will want to hold in stock, but through this approach we can give the best possible information across the whole market.”