Sector Focus: Steelmaking
Rolling Steel Construction Products
Rods and Bars
Welded Tube
“Shortly customers will be able to benefit from ArcelorMittal Section’s continued
investment in quality and service; in 2017 we started a €40 million programme of
upgrading the finishing facilities at our Differdange mill which includes the world’s
largest section roller straightener with a 2500cm³ modulus.”
ArcelorMittal Senior Technical Sales Engineer & Business Development, Neil Tilley
NSC 13
July/Aug 18
Sponsors
Steelmaking
Headline: ArcelorMittal, British Steel
Silver: Tata Steel
H shaped sections, angles and channels.
The nominal sizes of ‘universal beams’
(UB), ‘universal columns’ (UC) and ‘parallel
flange channels’ (PFC) are given in BS
EN 10365, which replaced the old BS4 in
February 2017. These sections are typically
defined by a serial size (nominal flange
width and section depth) and a weight per
metre created by varying the thickness
of the web and flanges. (Note that the
‘internal’ width between flanges is constant
for any serial size - it is determined by the
rolls - and an increase in flange thickness
results in a corresponding increase in
depth.) Dimensions for design, detailing
and resistance are given in the Steel for Life
Interactive Blue Book and the ArcelorMittal
Orange Book.
The nominal sizes of ‘angles’ are given in
BS EN 10056 and these sections are typically
defined by a serial size comprising the leg
length, either equal or unequal, and the leg
thickness.
Hot rolled open sections are produced in
lengths up to about 25m. A nominal yield
strength of 355N/mm2 is most commonly
used in construction, although 460N/mm2
sections are also available. Such sections are
typically supplied in either the As Rolled
(AR) or Thermomechanically Rolled (TM)
supply conditions, and are rolled from
continuously-cast blooms, billets or ‘dog
bones’.
Structural hollow sections
There are two basic methods of producing
hollow sections - the seamless process in
which a hole is pierced through a hot solid
bar to form the bore and then the bar is
rolled to form the round tube, and the
welded process in which a steel plate or
strip is formed into a cylindrical shape and
the edges welded together. The latter is the
most commonly employed for structural
applications. The High Frequency Electric
Resistance Welding (HFERW) method forms
the bulk of tube production in small and
medium sizes, up to 508mm in diameter.
Steel strip is uncoiled and guided, cold,
through sets of forming rolls to produce
the cylindrical shape. At the point where
the edges meet, a high frequency current is
introduced into the edges of the strip, either
by induction using an encircling coil or by
contacts sliding on the surface of the strip.
The electric current produces enough local
heat to melt the strip edges as they are forged
together. The weld is formed instantly. Pipes
of wall thicknesses above 16mm and with
diameters above 508mm are produced by
several consecutive forming processes and
Submerged Arc Welded (SAW).
Square and Rectangular hollow
sections are ‘squared up’ by passing them
through a suitable series of work rolls
that progressively changes the shape. This
reduction and reshaping process can be
carried out hot or cold, which results in
the distinction between ‘hot finished’ and
‘cold formed’ products. For a cold formed
rectangular section, the corner radius is
not as tight as can be achieved with the hot
process (which makes it easy to distinguish
the two types visibly). The mechanical
properties of hot finished and cold
formed can also vary and for this reason
it is unwise to consider these products as
interchangeable.
Hollow sections are typically produced
in lengths 6m to 14.5m, depending on
the size and thickness, and these sections
are typically defined by a serial size
comprising the outer dimension(s), and
the wall thickness. Dimensions for hollow
sections are defined in BS EN 10210-2 for
hot finished sections and BS EN 10219-2
for cold formed sections. A nominal yield
strength of 355N/mm2 is most commonly
used in construction, although 420N/mm2
hot finished hollow sections are also
available.
Furnace Reheat Hot Rolling Mills
LONG
PRODUCTS
FLAT
PRODUCTS
TUBE
MILL
Sections
Plate
Hot Rolled Light Gauge/Decking
/Design
/The_Blue_Book#Interactive_.22Blue_Book.22
/Steel_construction_products#Structural_hollow_sections
/Welding
/Welding#Submerged_arc_welding_.28SAW.29.2C_process_121