This was a by-invitation visit to take pictures for training and PR use, but it’s something you don’t get to see every day. This is actually two steelworks on two separate sites, but they work closely together – I’ll describe things in the order of how steel passes through the processes.
Site 1: The first stage is to unload the raw slabs of steel – these come by rail, 30 tons or so each, 10-15m long and 9-12″ thick.
The next stage is slab cutting – working volumetrically, the right size of slab is cut to produce a steel plate of the dimensions the customer asks for.
These slabs are then weighed – they’re about 10 tons each – then they go for reheating. There are two reheating processes used – pits and a pusher oven.
The pits are gas-fired at about 1200 degrees – the slabs stay in the pit for 3-4 hours to even out the temperature.
These were interesting pictures to take – standing on a 6ft-wide metal grating with 1200-degree ovens to either side, it was pretty warm Had to work quickly as well as the CO detector was going mad – we had to get special permission to get through the safety gates.
The pusher oven is a surprisingly simple continuous process. At one end, a magnetic crane is used to load the cold slab onto a conveyor.
A hydraulic pusher then pushes the slab into a gas-fired oven like a giant pizza oven. The oven has three zones, heating the slab to about 1200 degrees and stabilising the temperature. The oven holds 24 slabs, and each takes 3.5 hours to get through the oven. Pushing a new slab in one end of the oven drops a heated slab out the other slide.
One impressive, and slightly unnerving thing about a modern steelworks is how few people there are. There’s only one person at the pusher oven itself, the worker who loads the cold slabs. Everything else for both processes is controlled remotely from a control room with CCTV cameras.
From the reheating ovens, the slab travels by conveyor.
On to descaling, where a drench of cold water blasts the scale – the low-quality steel oxide – off of the surface of the slab.
The slab then goes onto the huge rolling mill – this mill uses several passes to turn a 10-ton, 12″-thick slab of red-hot steel into a 1-2″ thick sheet in about a minute, with a 3000psi, 500 litres-per-second water system. It’s an astounding thing to watch.
Like a lot at this works, it’s an interesting mix of high tech, very heavy industry, and old-fashioned skill – the thickness of the plate is measured by gamma rays and computer-controlled, but the positioning is done manually and all controlled from this control room.
From the rolling mill, the plates then go on for hot levelling, a first stage in making sure the plate is perfectly flat.
Then the still hot plates go to the cooling floor – here, the 200-degree plates are marked out for cutting by workers wearing rubber-coated wooden clogs, using chalk and string.
The rough edges are then cut off, and the plate sized to the customer’s specifications using an end cutter:
And side roller cutters:
Before going for cold levelling to make the plate completely flat.
Finally, the finished plates travel down an underground conveyor and off to despatch.
An interesting aside – this underground conveyor tunnel is still known as BP2. This dates from the war, when tunnels off of this were used as shooting ranges to test bullet-proof armour plate!
Site 2: At this site, the steel plate is quenched, tempered and cut to size for more specialist applications – this increases the strength of the steel.
The steel plate arrives by road from site 1 or other locations around the UK. It’s unloaded by magnetic gantry crane, and transported by conveyor.
The plate goes first to the austenitising oven – a giant pizza oven that heats it to about 900 degrees.
Then it’s immediately quenched with 100 bathtubs per second of tepid water.
From here, the tempered and cooled plate is transported again by gantry crane.
To cutting and testing – test samples are cut and sent off for analysis, and the plates are cut to requirements.
The cut plates are then taken to a giant cold levelling machine.
Then the finished plates are inspected and taken to a giant despatch hall to storage and loading onto flatbed lorries.