Steel production, vital to industries such as transportation and construction, is an extremely expensive and energy-intensive process.
Now an EPSRC-funded project, led by Warwick Manufacturing Group at Warwick University, is investigating the use of a new technology that could dramatically reduce the cost and amount of energy consumed by the process.
The Assure 2 project, which also involves McGill University in Montreal, Canada, and Tata Steel, could allow new advanced steels and steel alloys to be produced using the technology, which is known as belt casting.
In conventional steel production, the molten material is cast into continuous slabs of around 250 millimetres in thickness. These are cut into lengths, hot rolled, and then cold rolled, ultimately producing a strip of around 1mm thickness.
This is extremely energy-intensive, and steel makers have been investigating ways to improve the efficiency of the process by directly casting a thin strip of steel, according to Prof Claire Davis at WMG, who is leading the project.
“In belt casting you cast a strip directly onto a moving belt,” said Davis. “This strip is around 5-10mm thick, so there is very little rolling required to produce a product for the automotive industry, for example.”
Energy consumption accounts for around 20 to 40 per cent of the cost of conventional steel production. A significant portion of the energy consumed is in heating and reheating the steel.
Belt-casting could reduce this energy consumption by more than 3 gigajoules per tonne of steel produced, the researchers claim.
The technique could also allow new advanced high strength strip (AHSS) steel grades, including alloys containing aluminium or manganese, to be produced.
These materials have extremely attractive properties such as increased strength and lower density, but they cannot be produced using conventional processing, as it can lead to the creation of cracks, for example, said Davis.
“Belt-casting could potentially be used to manufacture these hard to produce, high value AHSS steels, in an energy efficient and cost efficient way,” she said.
The researchers will investigate the relationship between the belt casting process and the composition and microstructure of the materials produced.
They will collaborate with Prof Roderick Guthrie at McGill University, the world’s leading expert on belt casting technology, including using the university’s pilot plant facilities to investigate scaling up the process to commercial levels.
During one of several ‘summer-vac’ jobs, in 1961/2, I spent time at the Steel Company of Wales, in Port Talbot (or P’tlbt as the local steel masters called it!) Unless I am mistaken, one of the developments then in train was so-called “continuous casting” . Is this development an extension of that? I am aware that certain industries are somewhat conservative (that is a small ‘c’) but 55 years does seem a long period of gestation for something so important. I recall several large streams of hardening (still red) material exiting the retorts from a series of ‘lips’ and then passing onto rollers. Capital ‘C’ onservatives seem intent on removing steel-making from our economy entirely?
A good idea but you must be able to maintain quality control with the material composition and properties. Continuous steel making was tried here in Australia, but quality control appeared to be the biggest issue.
Ok , 3 gigajoules (GJ) sounds impressive but how many GJ are used to make a tonne of steel by conventional means? Numbers on their own like this are almost meaningless. Please put them in context or express as a percentage.
I googled a bit and it seems to take about 6-15MJ per kilo so presumably 6-15 GJ per tonne, assuming that the information isn’t bogus and that I am not mixing up tons and tonnes :-). hence it’s an improvement of anything from 1/5 to 1/2. Apparently, however, electricity is only 6% of the cost of steelmaking. This process might remove other costs too and it is also appropriate to high-spec steels so there is more to it.
What should be the reduction ratio to achieve the high strength structural steel sheets in belt-casting and can this be achieve by continuous rolling just controlling the temp in an on-line chamber with the required thickness slabs.