billet, rod, or tube are continuous cast, defined as the continuous solidification and withdrawal of product from an open-ended shaping mold. Methods include both vertical and horizontal casting, depending on product size, shape, and volume. Casting vertically has certain inherent technical advantages. The symmetry of cooling promotes a uniform and predictable solidification growth pattern and uniform axial loading on the freshly solidified shell as it is withdrawn from the mold. In tube or hollow section casting, the vertical process has particular merit. The disadvantages of vertical casting are mostly logistic: difficulty in handling long lengths of section; cut-off can be more difficult to engineer and control; and it is generally a semicontinuous operation. Horizontal casting requires lower capital investment, is compatible with lower production rates, and is a continuous operation. This article briefly reviews the history and methods of copper alloy continuous casting; the information is drawn from the very detailed and extensive coverage of the subject in Ref 1 and the numerous publications of equipment supply companies such as Rautomead, SMS Meer, and so on

1. Copper Continuous Casting*
Derek E. Tyler, Olin Brass (Retired)
Richard P. Vierod, Olin Brass
COPPER ALLOY PRODUCTS such as strip,
billet, rod, or tube are continuous cast, defined
as the continuous solidification and withdrawal
of product from an open-ended shaping mold.
Methods include both vertical and horizontal
casting, depending on product size, shape, and
volume. Casting vertically has certain inherent
technical advantages. The symmetry of cooling
promotes a uniform and predictable solidifica-
tion growth pattern and uniform axial loading
on the freshly solidified shell as it is withdrawn
from the mold. In tube or hollow section cast-
ing, the vertical process has particular merit.
The disadvantages of vertical casting are
mostly logistic: difficulty in handling long
lengths of section; cut-off can be more difficult
to engineer and control; and it is generally a
semicontinuous operation. Horizontal casting
requires lower capital investment, is compatible
with lower production rates, and is a continuous
operation.
This article briefly reviews the history and
methods of copper alloy continuous casting;
the information is drawn from the very detailed
and extensive coverage of the subject in Ref 1
and the numerous publications of equipment
supply companies such as Rautomead, SMS
Meer, and so on. Although a relatively simple
process, the metallurgical complexities of con-
tinuous casting involve the thermal and
mechanical interactions between the mold and
the moving solidifying shell of the casting.
The variations of alloy chemistry, physical,
thermal, and mechanical properties invoke
detailed changes in the process protocols.
The heat transfer within the mold is a key
factor in the successful production of a quality
product. The equipment suppliers have their
own proprietary designs for the mold assembly,
and some of the various design details of the
dies and cooling assemblies are described in
Ref 1. Typically, the molds (dies) are fabricated
from copper alloy components that may or may
not be sleeved with high-quality graphite
inserts. When sleeves are used, precise machin-
ing and polishing of the surfaces is essential to
provide intimate contact between graphite and
plate cooler to maximize heat transfer. Precise
control of the withdrawal parameters then
becomes of paramount importance.
History
Many of the techniques developed for copper
alloys have been adapted for aluminum and
steel. In a general timeline of developments
(Table 1), the breakthrough in continuous cast-
ing of nonferrous alloys can be credited to
Eldred in 1930 (Ref 2). He developed a
machine using graphite as the mold material
to cast copper rods and later a number of cop-
per-base alloys. Prior to that, the continuous
casting of metals had been practiced for almost
a century earlier with patents by Sellers and
Laign (Ref 3, 4).
In 1938, Poland and Lindner were granted a
U.S. patent (Ref 7) for a vertical casting
machine very similar to Eldred’s. The graphite
mold was cooled by a close-fitting metal water
jacket (Fig. 1). The potential of graphite as a
suitable mold material was quickly appreciated
by various companies, such as American Smelt-
ing and Refining Company (Ref 8) and Flocast
(Ref 17). The Asarco process (Ref 8), patented
*Portions adapted with permission from: Robert Wilson, A Practical Approach to Continuous Casting of Copper-Based Alloys and Precious Metals, Institute of Materials
(IOM Communications Ltd.), 2000
Table 1 Historical timeline of continuous casting
Year Development related to continuous casting of copper
1840 The first recorded patent in the nonferrous field was by Sellers for the manufacture of lead pipes (Ref 3).
1843 About the same time, Laign filed a patent in America for a method of continuous casting nonferrous metal
tube (Ref 4).
1914 U.S. patent was granted to Swedish engineer Pehrson for the first horizontal closed-head system for
continuous casting of cast iron bars (Ref 5).
Mid-1920s The Hazelett process was introduced as the first ingotless rolling plant for continuous casting of copper wire
rod (Contirod process) and production of continuous cast and sheared copper anode plate for electrolytic
refining (Contilanod) (Ref 6).
1930 Eldred developed a machine using graphite as the mold material to cast copper rods and later a number of
copper-base alloys (Ref 2).
1938 Poland and Lindner were granted a U.S. patent for a vertical casting machine very similar to Eldred’s
(Ref 7).
1930s The Asarco process was patented by the American Smelting and Refining Company for the continuous
casting of phosphorus-deoxidized copper (Ref 8).
Late 1930s The Properzi process was introduced in Italy to continuously cast and roll lead rod used for the manufacture
of lead pellets for shotgun cartridges. The plant is used today (2008) for the large-scale production of
aluminum rod and copper rod (Ref 9).
1950s An inexpensive machine for the continuous casting of bronzes was developed at the Tin Research Institute,
England (Ref 10).
Early 1950s United Wire, Edinburgh, patented their Unicast system for continuous casting brass and bronze rods
(Ref 11).
1957 The Swiss company Alfred Wertli introduced the first industrial horizontal continuous caster for the
production of cast iron rods and later expanded into continuous casting plants for a full range of
copper-base alloys and shapes—rod, billet, and strip (Ref 12).
1960s Technica-Guss of Wurzburg, West Germany, introduced horizontal continuous casting systems tailored to
individual customer requirements, producing strip, billets, round bars, tubes, and profiles in a range of
copper-base alloys (Ref 13).
1964 The Southwire Company of Carrolton, GA, introduced continuous casting of copper wire by the Southwire
continuous rod system, using a high-speed casting wheel mold (Ref 14).
1969 Outokumpu O.Y. of Finland introduced and patented the Outokumpu upward casting process for producing
copper rod (Ref 15).
1978 Rautomead Dundee introduced horizontal and vertical continuous casting equipment based on the
all-graphite system, with the Unicast principle of integrated melt, stabilization, and cast from a single
crucible (Ref 16).
ASM Handbook, Volume 15: Casting
ASM Handbook Committee, p 1019-1025
DOI: 10.1361/asmhba0005288
Copyright © 2008 ASM International®
All rights reserved.
www.asminternational.org

2. by American Smelting and Refining Company,
was primarily designed for the continuous cast-
ing of phosphorus-deoxidized copper, but it is
widely used today (2008) for a range of cop-
per-base alloys. The Properzi process (Ref 9)
was introduced in Italy in the late 1930s to con-
tinuous cast and roll lead rod used for the man-
ufacture of lead pellets for shotgun cartridges.
The plant is used today (2008) for the high-
volume production of aluminum rod and copper
rod.
Among the first production vertical casting
units to be introduced was the TRI equipment
developed by the Tin Research Institute in
England in 1950 (Ref 10). The equipment con-
sisted of an induction melting unit that feeds a
tundish, which was attached to a graphite mold
in a tapered steel water jacket. Withdrawal of
the product was by means of two grooved rolls
situated below the mold. Following the advent
of the TRI system, a number of vertical casting
processes appeared, such as the Unicast process
introduced by United Wire of Edinburgh. The
TRI and Unicast equipment filled a need for
equipment to produce tin bronze in the form
of rod and tube and also a selection of brasses.
Since the 1950s, United Wire plants have been
installed worldwide, particularly in Britain,
France, Italy, and the United States. Rautomead
has become a major supplier of such equipment
In 1957, the Swiss company Alfred Wertli
(Ref 12) introduced the first industrial horizon-
tal continuous caster for the production of cast
iron rods and later expanded into continuous
casting plants for a full range of copper-base
alloys and shapes—rod, billet, and strip. In the
1960s, Technica-Guss (Ref 13) of Wurzburg,
West Germany, introduced horizontal continu-
ous casting systems tailored to individual cus-
tomer requirements, producing strip, billets,
round bars, tubes, and profiles in a range of
copper-base alloys. In 1989, Technica became
a member of the Mannesmann Demag AG
group as Demag Technica GmbH and today
(2008) is a subsidiary of SMS Meer. The com-
pany is a supplier of horizontal and vertical
casting plants covering large installations for
billet and strip casting to smaller plants for
strip, wire, and tube casting of copper alloys
and precious metals.
Vertical Continuous Casting
(Ref 1, 18)
As noted, the Unicast system was developed
in the 1950s for vertical continuous casting of
bronze and brass rod approximately 16 to 19
mm (0.63 to 0.75 in.) in diameter as feedstock
for the manufacture of fine wire mesh used for
papermaking machines. The unit consisted of
an integrated continuous casting plant in which
the complete process of melting, alloying,
holding, and casting takes place in one self-
contained furnace (Ref 1). The Unicast furnace
differs from the modern version only in
that refractory brick insulation is used through-
out instead of low-thermal-mass insulation.
The integrated melting, homogenizing, and
casting in an all-graphite system produces a
high-quality product with minimal residual-
element impurities and low oxygen level, capa-
ble of being drawn to very fine wire. The initial
casting machines manufactured and used inter-
nally by United Wire were vertical casters of
approximately 1 tonne capacity with coiling
equipment to give workable coils for
subsequent rolling to 5 mm2
(0.008 in.2
) and
then drawn down to suitable wire sizes. United
Wire operates these casting units today (2008)
on a range of brasses, bronzes, and nickel-silver
alloys, producing rod of high quality.
A vertical continuous casting plant for cop-
per alloy tubes and bars consists of a channel-
type induction furnace, positioned on a tilting
frame and feeding into a water-cooled graphite
mold, with microprocessor-controlled with-
drawal system and automatic tube cut-off. Mold
or die change is made without emptying the
holding furnace by incorporating a back-tilting
mechanism, which is also a safety feature in
vertical casting, because the melting unit can
be tilted off the casting position in case of mal-
function. The product range in tubes is 20 to
125 mm (0.8 to 5.0 in.) outside diameter and
in bars 12 to 80 mm (0.5 to 3.1 in.) diameter.
Strand lengths are generally in the range of
3 to 4 m (10 to 13 ft).
Vertical Semicontinuous Slab Casters
Since the original invention of Unicast and
TRI vertical continuous casting, the most com-
monly used plant for slab casting is still the
proven design and low investment costs of ver-
tical semicontinuous casters (Fig. 2). The layout
consists of a casting pit with integrated casting
cylinder, by which the casting table and pro-
ducts are moved up and down. The liquid metal
can be supplied from the melting or holding
furnace via launder into the molds mounted on
top of the oscillating casting machine. It is
common for multiple molds to be mounted in
the casting table; this allows for very high
production rates.
At the end of the casting cycle, the produced
slabs are pulled out of the pit with an overhead
crane and a hydraulic tool for clamping of
the slab (Fig. 2b). This disadvantage can be
avoided by use of a vertical semicontinuous
caster with incorporated discharge device
(Fig. 3). This layout shows a larger casting pit
with integrated casting cylinder and casting
table, to which the discharge device is attached
by a swivel joint. The liquid metal solidifies in
the mold on top of the oscillating casting
machine. When the casting cycle is completed,
the cast slabs are pushed from the vertical posi-
tion slightly to the direction of the discharge
device, and the discharging operation starts.
The vertical semicontinuous slab casters can
be used to cast a wide range of alloys and sizes.
In addition to copper and brass, copper nickel
and other copper alloys are produced. Modern
casters incorporate components such as an auto-
matic melt-level control system to provide
automation and stable casting conditions for a
consistently good product quality. Also, adjus-
table slab molds can be used, by which the cast-
ing width can be varied and thus the inventory
of the molds reduced (Fig. 4). Most often,
copper alloy molds without sleeves are used
for slab casting.
Vertical Continuous Slab Casting
When casting copper slabs, the highest pro-
duction rates and consistent quality product
can be achieved with a fully continuous vertical
caster. The general layout is similar to the semi-
continuous mode; a holding furnace supplies
the liquid metal via an automatic melt-level
control into the molds, which are mounted on
top of the oscillating casting machine (Fig. 5).
The solidified strands pass through the second-
ary water-cooling box and are transported by a
withdrawal unit. After cutting, the products
are tilted by a tilting basket into a horizontal
position and further transported by a roller con-
veyor and lifting system.
Appropriate sensors detect the melt level in
the mold, and the flow of liquid metal is regu-
lated automatically by an electronic control.
The holding furnace is typically induction heated
and has a specific shape for vertical casting, with
an attached launder section or forehearth, thus
supplying the metal by the shortest route into
the mold without splashing.
The solidified slabs are firmly clamped and
transported by the withdrawal unit. The vertical
movable saw clamps to the strands and travels
together with the strands during the cutting
operation. After cutting, the products are taken
over by a tilting basket and tilted into a hori-
zontal position for further transport on
subsequent roller tables.
Fig. 1 Poland and Lindner vertical caster. Source:
Ref 1
1020 / Casting of Nonferrous Alloys

3. Upcasting Methods
The Outokumpu Upcasting Method. The
upward casting process was introduced and pat-
ented in 1969 by Outokumpu O.Y., Finland
(Ref 15), with the first production unit coming
into operation in 1970 for casting oxygen-free,
small-diameter copper rod. This system has all
the technical advantages of casting in the verti-
cal mode and, for small-diameter rod, none of
the disadvantages.
The method consists of a graphite die par-
tially immersed in molten metal, with the upper
part surrounded by a water-cooled jacket (Fig. 6)
(Ref 1). The assembly is located just above
the metal top surface, with the graphite die
only just immersed into the liquid and main-
tained precisely in position by an electronic
level-sensing control. The action of vertical
pulsed withdrawal of the rod raises the metal
beyond the lower extremity of the cooler, and
solidification takes place. In the melting and
transfer system, Outokumpu exposes the liquid
metal to graphite or charcoal, resulting in deoxi-
dation of the melt to a level of the order of 5
ppm oxygen. The machine operates on a multidie
system, casting, for example, 12 mm (0.5 in.)
Fig. 3 Vertical semicontinuous casting plant with
discharge device. Courtesy of Demag
Technica GmbH of SMS
Fig. 4 Adjustable molds for vertical semicontinuous
casting of slabs. Courtesy of Demag Technica
GmbH of SMS
Fig. 2 Vertical semicontinuous casting plant. (a) Layout without discharge device. (b) Slab discharging by overhead crane. Courtesy of Demag Technica GmbH of SMS
Copper Continuous Casting / 1021

4. diameter rods at speeds on the order of 3 m/min
(10 ft/min).
Rautomead Upwards Vertical Casting.
Rautomead International, Dundee, introduced a
modified upwards vertical casting process (Ref
16) based on graphite melt containment technol-
ogy and using submersed dies with inert gas pro-
tection. The equipment is used primarily for the
production of small-diameter, high-purity copper
rod with oxygen levels on the order of 5 ppm at
casting speeds on the order of 4.0 to 4.5 m/min
(13 to 14.5 ft/min). The machine is also adaptable
to alloy systems such as bronzes and brasses in
rod form and also tube. By utilizing an all-graph-
ite containment system and incorporating a spe-
cially designed graphite filter bed, deoxidation
of copper to 5 ppm oxygen is ensured.
Pressure Upcast System. A pressure Upcas-
ter (Ref 19) was developed as a production unit
at Dundee Institute of Technology (now Uni-
versity of Abertay, Dundee). During the casting
operation, an inert gas applied to the sealed
steel furnace casing exerts pressure on the mol-
ten metal in the graphite crucible, raising it into
the graphite die where it solidifies and is with-
drawn through a water-cooled jacket vertically
upward in a conventional pulsed mode. On
reverting to atmospheric pressure, metal drains
to the crucible. The equipment is primarily
intended for casting small-section high-purity
copper rod in the range of 1.5 to 10 mm (0.06
to 0.40 in.) in diameter.
A process using some of the same principles
was explored in the 1970s by Chase Brass to pro-
duce copper and brass rod. A higher throughput
was targeted, and the cast rod was reduced in-line
to wire. The process remains in use to produce
copper bus bar.
Horizontal Continuous Casting
Casting in the horizontal mode facilitates
product handling and generally occupies less
space. There are inherent problems as opposed
to vertical casting that mainly relate to grav-
ity-induced directional cooling, which, in most
cases, can be accommodated in the process pro-
tocols. The horizontal plants produce billets for
subsequent extrusion in copper or brass in sec-
tion sizes between 80 and 400 mm (3.1 and
16 in.) in diameter, operating as single- or mul-
tistrand machines. Smaller horizontal casters
are used for the production of tube, bar, and
sections in a full range of copper alloys.
The Swiss company Alfred Wertli (Ref 12)
introduced the world’s first industrial horizontal
continuous caster for the production of cast iron
rods and later expanded into continuous casting
plants for a full range of copper-base alloys.
State-of-the-art horizontal continuous casting
lines for copper alloys are mostly designed to
cast two narrow strips up to 450 mm (18 in.)
wide or one strip up to 800 mm (32 in.)
wide. Thin-strip withdrawal machines are
designed to cast two strands simultaneously,
or each strand can be independently withdrawn.
Fig. 5 Vertical continuous casting. Courtesy of Demag Technica GmbH of SMS
Fig. 6 Principle of upward casting. Source: Ref 1
1022 / Casting of Nonferrous Alloys

5. The molds can also be configured for billet
casting 100 to 400 mm (9 to 16 in.) in diameter,
bar and tube casting in the size range of 25 to
350 mm (1.0 to 14 in.) in diameter, and for
small-diameter rod and wire 12 to 25 mm (0.5
to 1.0 in.) in diameter.
The original Wertli (Ref 12) concept consists
of a channel-type induction furnace and holding
furnace, together with graphite die and cooler
assembly and runout track with withdrawal
machine and cut-off device. Molten metal flows
from the melting furnace to a holding or casting
furnace that acts as a reservoir of molten metal,
maintaining the required casting temperature.
Water-cooled graphite dies are attached to
the holding furnace or crucible. During the con-
tinuous casting operation, metal flows into the
graphite casting die, where it solidifies. The
solidified strands are intermittently withdrawn
in a pull-pause sequence by means of with-
drawal equipment. After leaving the graphite
die, which is housed within the primary cooler,
the cast strands pass through a secondary cooler
in the form of a water sparge that removes the
surplus heat contained in the solidified casting.
The crucible can be manufactured in a refrac-
tory ceramic or from graphite. Integral ceramic
crucibles are used extensively in induction
melting and casting furnaces. These are the
most energy-efficient furnaces and consist of
melting units feeding a casting unit or a single
induction-heated casting unit. The design varies
depending on the application. The metal type
and production rate will determine the crucible
capacity and power rating. Frequency is chosen
to suit these parameters and is selected from
150, 250, 500, 1000, 3000, and 10,000 Hz.
The high frequencies apply to small crucible
capacity, decreasing for the larger installations.
Induction melting and casting furnaces use
either integral or removable crucible assem-
blies, depending on the casting operation.
Precast ceramic crucibles with graphite sup-
port carriers are used in either induction-heated
or resistance-heated furnaces (Ref 1). The full
range of Rautomead graphite resistance-heated
furnaces use this basic design, ranging from
small table-top units to installations with crucible
capacity of 2500 kg (5500 lb) (copper).
Graphite can only be used in a nonoxidizing
atmosphere; therefore, the crucible and die
assembly must be housed in a sealed furnace
and protected with an inert gas, either nitrogen
or argon. Most high-grade coppers, brasses, tin
bronzes, phosphor bronzes, and aluminum
bronzes can be successfully cast in an all-
graphite crucible and die assembly (Ref 1).
The volume of the crucible is dependent on
the application and may vary in capacity from
several tonnes to 1 kg (2 lb) or less.
A crucible liner or protecting sleeve is fre-
quently fitted, particularly with larger crucibles.
This liner is manufactured in graphite and pro-
tects the main crucible against abrasion and
oxidation. The seal between crucible and graph-
ite die is often made by means of a grafoil gas-
ket sheet or washer. Grafoil consists of graphite
in flexible lamellar form, which is compress-
ible, forming a gastight seal and providing a
liquidtight seal.
Graphite baffles can be fitted within the cru-
cible and held in position between the lower
and upper graphite sleeves or liners (Ref 1). A
baffle with suitable perforations provides an
upper and lower chamber to facilitate melting
and homogenization of the charge in the upper
section prior to this metal entering the casting
die. Another, most important function is to
allow sufficient time for deoxidation of the melt
and thus avoid attack on the graphite die.
Unicast Horizontal Casting System. In the
early 1970s, the first Unicast horizontal casting
plant was installed by Timex Corporation, Dun-
dee, for continuous casting brass rod for watch
case manufacture, operating under conditions
similar to the United Wire vertical casters. This
operation was extremely successful, utilizing as
feedstock 100% internally generated brass scrap.
The recycled scrap from trim and machining
operations on case manufacturing, together with
high-quality press shop and screw machine
residue, made the process economically viable.
The chemistry of the product could be closely
controlled, reducing trace element impurities to
limits unobtainable on purchased stock.
Since its inception in 1978, Rautomead, Dun-
dee, has manufactured a wide range of continu-
ous casting machines for the nonferrous metals
industries, primarily for copper-base alloys and
precious metals. The Rautomead resistance-
heated all-graphite system is based on the
United Wire Unicast technology. The design
has been refined, particularly in the area of
refractory insulation heating element configura-
tion and unit modular construction. The major-
ity of the machines operate in the horizontal
mode, with a few special-purpose machines
casting vertically downward.
The construction of the Rautomead machines
is an integrated all-graphite melt-and-cast sys-
tem. The casters range from small table-top
units with crucible capacities of 2 to 50 kg
(4.5 to 110 lb) (copper) to large billet and strip
casters with crucible capacities to 2500 kg
(5500 lb) (copper).
Strip Casting
The horizontal strip casting process was orig-
inally developed by Technica-Guss, which is
now part of SMS Meer. It has been widely used
in the industry for more than 30 years as a near-
net shape casting process for alloys that are
considered difficult to hot roll, such as nickel-
silver mint alloys and phosphor bronze for
electronic applications.
Horizontal continuous casters are manufac-
tured for casting a range of strip widths. Typi-
cal strip widths are 450 mm (18 in.), 650 mm
(26 in.), or larger, with a common thickness
being between 14 and 20 mm (0.6 and 0.8
in.). The produced coil can be automatically
discharged onto a subsequent discharge table.
A majority of horizontal strip casters are
equipped with an in-line milling machine by
which the top and bottom of the cast surface
is cleaned of oxides and segregations so that a
perfect coil is produced for direct passing into
the cold rolling mill.
Modern strip casters comprise high-perfor-
mance coolers with temperature-sensoring sys-
tems to survey the solidification and apply
nitrogen for reduction of surface oxides. Fur-
thermore, a tight temperature control in the
holding furnace is essential for stable casting
conditions and product quality, which is rea-
lized with the stepless power control of the
inductor by the inverter technique.
A typical casting speed of a horizontal strip
caster is up to 200 mm/min (8 in./min), result-
ing in a production of approximately 6,000
tons/year for strips 650 by 16 mm (26 by 0.6
in.). Due to the limited production rate, many
companies who are using this casting process
operate several machines; even eight machines
are in operation in one company. Horizontal
strip casters are used exclusively for the pro-
duction of copper alloys and, in very few
exceptions, worldwide for copper. To overcome
the limitations of the thin-strip casting process
regarding output and copper casting, SMS Meer
developed a new concept for a vertical strip
caster (Ref 18).
Wertli Strip Casting. The Wertli strip cast-
ing plants include in-line operations such as
milling equipment, traveling shear, coiler, and
die and track friction. Hydraulically amplified
electric drives are used to achieve forces in
the range of 40 to 80 kN (9000 to 18,000 lbf)
while maintaining motion accuracy. The Wertli
drive concept is designed to handle such forces
and accelerations by using backlash-free low-
ratio gears together with a high-precision servo
motor with hydraulic amplification. To achieve
a mechanically backlash-free drive, backlash-
free gears are used between the driving motor
and the rollers that drive the strands. Slippage
between the cast strand and the drive roller is
to be avoided if a precise strand motion must
be maintained over long periods of casting.
The tight gripping of the strands is achieved
by hydraulic press-down cylinders. A cooling
system with an enhanced water-cooled surface
increases heat transfer (approximately 10%)
compared to a conventional copper plate cooler
(Ref 1).
Hazelett Casting Process. The Hazelett
steel belt casting invented in 1920 has been
developed for various product forms and today
(2008) is used in the production of copper wire,
rod, strip, and anode. The metal is usually
melted by induction and is delivered via a
tundish to a straight-through mold formed by
tensioned steel belts and edge dam blocks.
Fast-film heat extraction from the mold is
achieved by a proprietary design for the appli-
cation and removal of high-flow-rate water
cooling. The use of special coatings on the belt
is also important. Strip up to 1.25 m (4.10 ft)
wide and Contirod, a rectangular cast bar at
Copper Continuous Casting / 1023

6. 6 to 60 tonnes/h depending on plant capacity,
can be achieved. The Contilanode process is
used for producing high-quality copper anode.
The cast anode plate can be maintained geomet-
rically to within close limits. Hanger lugs are
cast in shaped recesses and thus become an
integral part of the anode body.
Wheel Casting
Properzi Wheel Casting Technology. Prop-
erzi first used wheel casting technology on cop-
per in the 1950s and commercially introduced
the continuous casting and rolling process for
copper rod in 1963. Molten copper is poured
into a revolving casting wheel from a gas-fired
melting and refining furnace. The copper rim
of the wheel is grooved to receive the molten
metal, which is then retained in the groove by
a steel belt. The solidified metal leaves the
wheel and passes through a rolling mill without
interruption.
The casting wheel has a “U” profile, a shape
that evolved to control solidification and heat
transfer as the metal traversed the cooling seg-
ments of the wheel. A Cu-Cr-Zr alloy mold is
used for the casting of all electrolytic tough
pitch (ETP) copper. The position, alignment,
and adjustment of the individual cooling spray
nozzles located around the wheel are of the
utmost importance in controlling the solidifica-
tion and uniformity of the grain structure of
the cast bar.
A layer of acetylene soot, applied to both
cavity and band, serves as a release agent and
insulator, which provides uniformity of heat
transfer. During each rotation of the wheel,
the soot is stripped by high-pressure water
sprays, then reapplied.
The cast “D” section passes through two two-
high break-down roll stands, followed by six to
eight three-high roll stands to yield product for
rod, narrow strip, trolley wire, and other
applications.
Southwire Continuous Casting Rod
Process. Following some research and develop-
ment with Properzi in approximately 1960, the
Southwire Company of Georgia, United States,
introduced a continuous casting process for the
high-speed production of ETP copper rod. The
process has been described in detail in several
published papers (Ref 20–23). The SCR
process, as it is known, incorporates a continu-
ous melting, holding, casting, rolling, pickling,
and coiling system.
The casting wheel provides a trapezoidal-
shaped casting groove in the periphery of a cop-
per alloy ring. This ring is closed by an endless
steel belt through an arc of approximately 180
to 210
, the belt being held in place by idler
wheels and tensioners. The casting groove and
the contact side of the steel band are coated
with a controlled layer of soot that serves as a
release agent and provides uniformity of heat
extraction. The cast bar passes to the rolling
mill through a trimming and descaling
operation. The mill itself is composed of a
number of roughing, intermediate, and finishing
two-roll stands. The alternating vertical and
horizontal shaft stands produce a repetitive
series of oval-to-round reductions.
In the continuous casting of ETP copper with
oxygen content in the melt of approximately
400 ppm, the dissolved oxygen reacts with the
impurities present during solidification, precipi-
tating these out of the solid solution and result-
ing in improved annealability and electrical
conductivity of the product.
The claim for success of the SRC process is
the ability to control the amount of superheat
to a very close range immediately prior to cast-
ing, generally approximately 25
C (45
F)
above the liquidus. The use of a high-purity
cathode and the close control of temperature
results in solidification in a columnar grain pat-
tern with good bar quality. In subsequent roll-
ing in the SCR process, the high temperature
and severe initial reductions in the first pass
cause dynamic recrystallization. Chia (Ref 24)
described the mode of solidification on SCR
tough pitch copper rod.
Ohno Continuous Casting Process
The Ohno continuous casting concept is
based on the application of the Ohno separation
theory of solidification (Ref 25), with the con-
tinuous cast ingot consisting of unidirectional
solidified structure with no equiaxed crystals.
The process is described by Ohno and McLean
(Ref 26).
The patented process (Ref 27) differs from
conventional techniques in that molten metal is
poured into a heated mold rather than into a
cooled mold or die. The mold is heated exter-
nally and its temperature maintained above the
solidification point of the metal being cast. As a
result, no metal nucleates on the mold surface.
The Ohno process has been adopted by Furu-
kawa, Japan (Ref 28), for the production of
oxygen-free high-purity copper rod. The rod
has a structure characterized by longitudinal
crystals or may even develop into a single crys-
tal in some growth conditions. This special
structural material is used in high-resolution
audio signal transmission, having low impuri-
ties, no grain boundaries transverse to the direc-
tion of signal transmission, smooth surface
finish, and excellent physical properties.
The production casting equipment used is
essentially as shown in Fig. 7, with some refine-
ments, including a melting furnace and a cast-
ing furnace with precise metal-level control,
ensuring constant metastatic pressure on the
solidification front. The high-purity copper
charge is deoxidized using carbonaceous mate-
rial in the melting furnace before transfer to
the casting furnace.
REFERENCES
1. R. Wilson, A Practical Approach to
Continuous Casting of Copper-Based Alloys
and Precious Metals, Institute of Materials
(IOM Communications Ltd.), 2000
2. B.E. Eldred, U.S. Patent 1,868,099, 1932
3. G.E. Sellers, U.S. Patent 1908, 1840
4. L. Laign, U.S. Patent 3023, 1843
5. A.H. Pehrson, U.S. Patent 1,088,171, 1914
6. Hazelett Process, Iron Steel Eng., Vol 43
(No. 6), 1966, p 105
7. Poland and Lindner, U.S. Patent 2,136,394,
1938
8. A. Kreil et al., Asarco Process, Met. Rev.,
Vol 5, 1960, p 413–446
9. Properzi Process, Met. Rev., Vol 6
(No. 22), 1961
10. E.C. Ellwood, J. Inst. Met., Vol 84, 1955–
1956, p 319–326
11. I.E. Ewen, United Wire Unicast Process,
U.K. Patents 894,783, 894,784, and 934,484
12. T.P. Wertu, Alfred Wertli AG, Winterthur,
Switzerland
13. Technica Guss, Wurzburg, West Germany
Fig. 7 Schematic of Ohno continuous casting. Source: Ref 1
1024 / Casting of Nonferrous Alloys

7. 14. Southwire Revolutionizes Non-Ferrous
Rod Production with SCR System,
Vol. 33, Southwire Mag., June 1975
15. M. Rantaneno, Upward Continuous Cast of
Copper Wire, Wire Ind., July 1976
16. Rautomead International, Dundee, Scotland
17. A. Krell et al., Flocast Process, Met. Rev.,
Vol 5, 1960, p 413–446
18. “Copper and Copper Alloy Rolled Pro-
ducts—Trends in Equipment/Auxiliaries
and Applications,” Seminor at Hotel Le
Royal Meridiea (Mumbai), Jan 18–19,
2006
19. R. Wilson, Pressure Upcast, U.K. Patent
GB 2,236,498B, 1992, and U.S. Patent
5,090,471, 1992
20. U. Sinha and R. Adams, Southwire Contin-
uous Rod Process: Innovations for Quality
Improvements, Wire J. Int., June 1993
21. U. Sinha and R. Adams, “Southwire Con-
tinuous Rod: A Method to Produce High-
Quality Rods for Fine Wire Drawing and
Special Applications,” Conference Indian
Copper Development Centre and Winding
Wires Manufacturers Association of India,
Oct 1988
22. G.T. Hudson, “The Production of Copper
Rod by SRC Process,” internal paper,
Southwire Company, Carrolton, GA.
23. L.C. Richards et al., “Continuous Casting—
Its History, Impact and Future,” Metals
Week Copper Conference, Dec 10, 1989
24. H. Chia, International Conf., Inst. Wire and
Mach. Assoc. (Torremolinos, Spain), April
1979
25. A. Ohno, Solidification, The Separation
Theory and Its Practical Application,
Springer Verlag, New York
26. A. Ohno and A. McLean, Ohno Continuous
Casting, Adv. Mater. Process., Vol 4, 1995,
p 43–45
27. A. Ohno, Japan Patent 1,049,148; U.S.
Patent 4,515,204; and Germany Patent
3,246,470
28. K. Nakano, “Continuous Casting of Copper
and Copper Alloys,” RD Division of
Furukawa Electric Company, Japan
Copper Continuous Casting / 1025