Sector Focus: Steelmaking
12 NSC
July/Aug 18
Semi-finished billets, blooms and
slabs from the continuous casting
process (see NSC Sept 2017) are
transformed into a variety of construction
products by various processes of heating and
mechanical working. The resulting products
are either used directly in the fabrication
of steel components, that are subsequently
assembled into structures on site, or made
into further products for use in construction.
Shaping Steel
Steel is a strong material that is highly
resistant to shaping at normal temperatures,
but this resistance lessens considerably
at higher temperatures. For that reason,
the billets, blooms and slabs from the
steelmaking process are shaped into basic
products at carefully controlled elevated
temperatures.
The method that is most commonly used
for shaping is to heat the steel to around
1280°C in a reheat furnace and then roll the
steel, squeezing it between sets of rolls. Rolls
are arranged in pairs, either just horizontally
or both horizontally and vertically, and
housed in a ‘stand’.
To change the shape of a material as
strong as steel the rolls must exert forces
measured in hundreds of tonnes and must
also draw the steel continuously through
the rolls while reducing the thickness. Two
main classes of product are produced - flat
products such as plates, sheets or strips of
uniform thickness, and long products which
are lengths of a particular cross section,
ranging from rectangular bars to double
flange H sections.
For flat products, two horizontal rolls are
set one above the other in an open housing.
These work rolls that contact the hot steel
are often supported by larger diameter rolls
to prevent them bending under the rolling
loads to ensure a uniform thickness product.
For long products there are two types
of mills; structural and universal. In a
structural mill there are multiple stands
each containing specially shaped rolls where
the full set of rolls gradually shape the hot
steel in successive passes through separate
roll gaps. The product passes through each
roll gap only once. In a universal mill the
stands contain both vertical and horizontal
rolls and the hot steel passes backwards and
forwards through the same mill multiple
times with the shape being formed by
reducing the gap between rolls on successive
passes.
Plates
Plates are available in a wide range of grades
and sizes. For use in building construction
plate will normally be welded into fabricated
sections.
Normal plate sizes range from 5mm to
200mm thick, with widths up to 3.5m and
lengths up to 18.0m. Plates with a nominal
yield strength of 275N/mm2 or 355N/mm2,
commonly used in construction, can be
supplied in either the As Rolled (AR),
Normalised (N), Normalised Rolled (NR)
or Thermomechanically Rolled (TM)
supply conditions, and are rolled from
continuously-cast slab.
Close control of chemical composition
is maintained to produce clean steels with
consistent strength and toughness properties
that meet all relevant national standards, as
with all structural products, and state-ofthe
art levellers produce flat plates with
controlled residual stress.
Strip
Strip steel is used to produce many different
products and in many applications. It is
available in three main forms.
• Hot rolled
• Cold rolled
• Hot-dipped galvanized coil.
The most common form of strip steel used
in construction is hot-dip galvanized coil.
The typical thickness used in construction
is 0.4 to 3.2mm. It is generally available in
coiled form in widths from 900 to 1,800mm.
Standard open sections
Open sections commonly used in
construction range from large columns,
beams and piles down to smaller products
including channels and angles.
Various types of mill are used to produce
different long products. For example, heavy
section and medium section mills have three
or four stands using rolls with specially
machined profiles corresponding to the
initial roughing, and the intermediate and
finishing stages of rolling.
British, European and International
standards define dimensions for a wide
variety of open section shapes, such as I and
An introduction to steel
construction products
In this sector focus article, New Steel Construction provides an
overview of the various forms of steel construction products and
describes how they are produced.
Semi-finished Products Blooms
Billets
Furnace Slabs
“We pride ourselves on the quality of our products and services, and our ability to
respond to customer requirements.
“Our steel is produced to the highest standards - well within the tightest
dimensional tolerances – and we’ve a proven track record of delivering costeffective
solutions for developments of all sizes, from skyscrapers and sports stadia
to schools and shopping centres.
“We continue to invest in our manufacturing operations to further improve the
quality of our steel, and we also have an established network of distribution centres
across the UK and Ireland. In doing so, we’re not only able to offer a first class service
but offer great value in the UK steel construction supply chain.”
British Steel Managing Director Construction, Richard Farnsworth
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/Fabrication
/Construction
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/Steel_construction_products#Flat_products_-_plates
/Steel_construction_products#Fabricated_products
/Steel_construction_products#Fabricated_products
/Steel_material_properties#Yield_strength
/Steel_material_properties#Toughness
/Steel_construction_products#Flat_products_-_strip
/Metallic_coatings#Hot-dip_galvanizing
/Steel_construction_products#Standard_open_sections