Innovations
in the Sub Arc process
New technologies and specialized consumables
for the continuous improvement of welding productivity
ESAB - 100 years of we
1904 - Oscar Kjellberg invents arc welding with
2004 – ESAB develops new Multiwires submerge
ESAB has devoted 100 years to welding in leading
position in the research and development of
processes and products innovation, since 1904
when Oscar Kjellberg invented the first covered
electrode. ESAB’s mission is to supply to the
welding industry the best possible solution, product
and process technologies.
The result achieved in 100 years is remarkable: the
productivity of the welding processes has increased
by 100 times, from 1 kg/hour of the first electrodes
for manual welding to 100 kg/hour of the latest
equipment for Multiwires submerged arc welding.
Thanks to the possibility to use current values of up
to 1000 A on a single 4 mm wire, the SAW –
Submerged Arc Welding process offers a much
higher productivity than the other welding
processes.
Tandem welding head
DC+AC
Single welding head
Twin-Arc
Single welding head
Single cored wire
Single welding head
Single solid wire
20 kg/hour
12 kg/hour
8 kg/hour
5 kg/hour
elding productivity
covered electrode: deposition rate <1 kg/hour
ed arc welding techniques: deposition rate up to 100 kg/hour
The SAW process can deposit a considerable quantity of high quality welded
metal, at a low total welding cost in a wide range of applications. In the search
for higher productivity, ESAB has developed the Multiwires welding technology,
with equipment using up to 6 wires simultaneously, reaching a deposition rate of
100 kg/hour.
Six-Arcs welding head
1DC+5AC
Twin tandem welding head
+ cold wire
Triple-Arc welding head
1DC+2AC
100 kg/hour
Single welding head
+ cold wire
50 kg/hour
Deposition
rates
for submerged
arc welding
from 5 to 100 kg/hour
with the new technologies
40 kg/hour
25 kg/hour
ESAB - Multiwires
Multiwires submerged ar
New methods for the continuous improvemen
Twin-Arc
1
1
1
2
Welding head
DC power source
PEH control panel
Wires in the same torch
This welding technique uses two wires, spaced at a distance of
approximately 8 mm with a single torch.
Current is produced by a single power source for the two wires,
which are also guided by a single wire-feeder.
Therefore it is possible to use double current and feed values
compared to those of the single wire. The Twin-Arc process also
permits a highly flexible deposition rate.
With few components and a limited investment it is possible to
convert a single-wire ESAB A6 equipment into a Twin-Arc
equipment.
Tandem
2
1
1
2
Welding heads
DC power source
AC power source
PEH control panels
This technique differs from the Twin-Arc as it uses two wires
guided by separate feeding systems and fed by two different
power sources, even if they form the same weld pool. The
greater penetration force of the arc fed with DC is used on the
first wire to ensure optimal penetration at the bottom of the
chamfer, while the second wire is fed with AC, performing the
joint filling function. The DC/AC system is used for applications
with one or more passes, but for multi-pass welds, the AC/AC
system can be used when a high penetration is not required.
Single welding head +
synergic cold wire
1 Welding head - 1 DC power source
1 Motor for welding wire + cold wire
1 PEH control panel
The cold wire submerged arc welding technique was invented in
the ESAB laboratories in 1998 and offers an increase by over
50% in the deposition rate. It consists in the insertion in the weld
pool of a cold wire, in synergy with the welding wire.
The cold wire can be inserted in front of or behind the welding
wire, depending on whether penetration or filling is more
important. The system makes it possible to use different
materials for the cold wire to produce particular metallurgical
properties, and it is ideal for high quality welds and special steels.
rc welding equipment
nt of performance and productivity
Tandem-Twin
+ synergic cold wire
2
1
1
2
Twin-Arc welding heads + cold wire
DC power source
AC power source
PEH control panels
The Tandem-Twin technique with double synergic cold wire
combines the advantages of the three techniques illustrated above,
and makes it possible to reach extremely high deposition rates, up
to 50 kg/hour, with high speeds and without using multi-pass even
for greatest thicknesses. It is also possible to get a high penetration
and an effective joint filling thanks to the DC and AC combination of
the two welding heads. The insertion of the cold wires in the weld
pool makes it possible to reduce the heat input and the dilution.
Moreover, it is possible to achieve the best control of the
metallurgical properties, using various wire combinations.
Triple-Arc welding head
3
1
2
3
Welding heads
DC power source
AC power sources
PEH control panels
When high welding speed is needed on big thicknesses with
single pass, for example in pipe factories and ship prebuilding,
the three-wire system offers great advantages. In fact, speeds
and deposition rates four times higher than those of single-wire
welding can be reached. DC is normally used for the first wire, to
reach maximum penetration, the second AC wire performs the
filling, while the last AC wire usually operates at lower current a
finishing function.
Six-Arcs welding head
6
1
5
6
Welding heads
DC power source
AC power sources
PEH control panels
It is a particularly suitable method for the production of pipes
longitudinally welded. The welding speed can reach 10 m/min
and the deposition rate 100 kg/hour. High welding speed means
less heat input and consequently better mechanical
characteristics. At present the machine is used in the
development centre of the ESAB welding processes in Goteborg
to test and develop new processes and new wire-flux
combinations for high quality steels for pipe lines, like X-70 and
beyond. In fact, the growing demand for pipe lines requires the
use of very strong steels with thinner thicknesses, to reduce the
weight and therefore the costs of the pipe lines.
Solid wires, cored wires an
The correct choice of the consumables and wire + flux combi
Two basic requisites must be met for the components welded with the submerged arc process: the service
conditions of the base materials and the productivity. In fact, both may influence the choice of the
consumables (wire + flux) to be used in production.
The aim is to perform a welded joint which meets the requirements of the base material (e.g. Tensile strength,
resistance at low temperatures) in the shortest possible time. However, the productivity needs remain tied to
the single applications and are connected with other factors like the type of joint, the available equipments
and the manufacturing cycles.
The wire choice
• Mild wires in carbon steel (C, Mn, Si) : general steel
structures, shipbuilding, plants (welded beams).
OK Autrod 12.20/12.22/12.24 + OK Flux 10.71
OK Autrod solid wires
As a general rule it may be said that the chemical analysis of the
consumables must be as close as possible to that of the base
material as far as the main or alloyed elements are concerned.
Exceptions are permitted if particular requisites (i.e. resilience at
low temperature), not otherwise possible without the use of low
alloyed wires, even if these are absent in the base materials.
It is possible to group in families different types of wires and
identify the market segment in which their use is the most
common.
OK Tubrod cored wires
Since years Esab has had the availability of carbon steel or low
alloyed cored wires for submerged arc welding. The cored wires
are the cheapest means to obtain a weld deposit of even
complex chemical composition when the equivalent solid wires
are not available on the market, extremely expensive or even not
manufactured.
The cored wires for rolls cladding (steel mills, ship masts etc,) are
typical examples, even if an aspect often not taken into due
consideration is the large difference in productivity compared to
the solid wires. In fact, it can easily be said that the productivity
increase under normal conditions of use is over 30% compared
to a solid wire. Also available in spools of standard weight of 30
kg or in 300 kg drums, they have the advantage of being able to
be used without changes and/or modifications to the existing
welding equipment. Similarly to the solid wires, they can be
grouped, according to the chemical analysis for the use, in the
same market segments.
Comparison of deposit speed with single wire
OK Tubrod 15.00S + OK Flux 10.71
OK Autrod 12.20 (S2) + OK Flux 10.71
• Wires in carbon steel (C, Mn, Si, low impurities):
storage industry (tanks), boilers (heat exchangers,
offshore).
OK Autrod 12.22/12.32 + OK Flux 10.62
• Wires in carbon and low alloyed with Mo (C, Mn, Si, Mo):
wind towers, boilers.
OK Autrod 12.22/12.24 + OK Flux 10.72
• Wires low alloyed with Cr-Mo: boilers (pressurized
apparatuses for high temperatures), processing industries
(refineries).
OK Autrod 13.10/13.40 + OK Flux 10.62
• Wires alloyed with Cr-Mo-V (P91): thermoelectric power plants.
OK Autrod 13.35 + OK Flux 10.93
• Stainless wires alloyed with Cr-Ni-Mo: processing
industries (refineries), food industry, chemical industry.
The entire stainless range + OK Flux 10.92/10.93
nd fluxes for all applications
ination determines joint quality and productivity
The flux choice
Agglomerated fluxes
They are fluxes obtained by dry-mixing the
ingredients.
These ingredients are then “alloyed” together
by compounds with low melting point like
sodium silicates. The agglomerates
contain metallic deoxidizers to prevent
porosity in welding.
These fluxes absorb the humidity from
the environments and must therefore
be correctly stored before use or
submitted to a drying treatment.OK
flux 10.71 and OK 10.62 are
agglomerated fluxes. The agglomerated
fluxes are those most widely used in the
Italian market and have replaced the
common practice of using fused fluxes.
Fused fluxes
After mixing, the ingredients are placed in ovens and fused.
When the compound has cooled, it is ground to obtain grains
of identical chemical analysis and of the required dimensions.
The fused fluxes do not contain water based alloys
and therefore do not fear humidity.
OK Flux 10.40 and OK 10.45 are fused fluxes.
Active and neutral fluxes
All the fluxes interact with the base materials and influence
their composition and mechanical characteristics. It is
common to classify a flux as active if it adds Silicon and
Manganese in the weld pool. However, this addition is always
proportional to welding voltage and to the flux quantity used.
Its use is recommended for one, maximum three weld beads.
With the neutral fluxes there are not significant transfers of
Silicon and/or of Manganese in the weld pool and they are
therefore recommended for multipass applications for joining
low alloyed or high strength steels.
However, it is important to stress that the original distribution
between acid and neutral fluxes has been extended through
the introduction on the market of the so-called basic or highly
basic fluxes.
Strip cladding
Specific fluxes are available for cladding and rebuilding
with strip, for the submerged arc and electroslag
processes.
OK Flux 10.05 + austenitic strips (SAW)
OK Flux 10.10 + austenitic strips (ESW)
OK Flux 10.14 + austenitic strips (ESW
high speed and high current density)
OK Flux 10.16 + strips with nickel base (SAW)
OK Flux 10.11 + strips with nickel base (ESW)
ESAB A6 system
A modular system with components, to build
“made to measure” submerged
arc welding installations
The A6 system offers the best solution for all submerged
arc welding applications. Its modularity and wide range of
power sources make it possible to develop the most
suitable SAW installation for production needs.
The head can be completed with motorized slides
and a guide system which automatically
follows the joint, and maintains the correct
stick-out regulation: it is possible to
upgrade it at any time to exploit the Esab
Multiwires solutions,
without having to
change the basic
equipment.
The welding head can
be installed on
gantries, on column
and booms, on beam
carriages, or on tractors.
All “made to measure”
for you by Esab.
Esab reserves the right to make modifications without notice.
If you wish to receive further information, photocopy this page, compile it and send it by fax or, if you prefer, by post. We will
send you the required material.
Consumables for submerged arc welding
Plants for automatic welding
Name
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Number of welders in the company
ESAB Saldatura SpA
Via Mattei 24, 20010 Mesero – MI – Italy
Tel.+39 02 97968 1 – Fax +39 02 97289 181
www.esab.it
e-mail: esab.saldatura@esab.se
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MARCS - T - 05K - 0604
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