This document discusses multi-wire submerged arc welding. It describes the basic equipment used, which includes a wire feeder, welding power source, and flux feeding arrangement. It then focuses on twin submerged arc welding, which involves feeding two wires in parallel through the same contact tip to increase melt production and stability compared to a single wire. Schematics and diagrams show how twin welding is arranged. Higher deposition rates of up to 38kg/h are possible using four 2.5mm diameter wires in a tandem twin configuration. Parallel and series twin wire configurations are also explained and compared. Charts provide data on deposition rates achievable using single versus twin wire setups. Applications of the twin arc system are mentioned.

1. Multi wire Submerged Arc
Welding
Presentation prepared by :
Kunj Thummar
140050119517

2. Basic Equipment
 A wire feeder to drive the electrode to the work through the
contact tube of welding gun or welding head
 A welding power source to supply electric current to the
electrode at the contact tube
 An arrangement for holding the flux and feeding it ahead of the
arc
 A means of traversing the weld joint
Twin torch

3. Twin Submerged Arc Welding
 Twin arc welding involves feeding two wires in parallel through the same contact tip.
 It differs from tandem welding in using only one power unit and one wire feeder.
 In comparison with the use of a single wire, twin arc welding results in a higher rate of melt
production and improved stability.
 A twin-arc welding machine can be easily produced by fitting a single-wire machine with feed
rollers and contact tips for two wires.
 Without very much higher capital costs, it is possible to increase the deposition rate by 30-40 %
in comparison with that of a single-wire machine.
 Wire sizes normally used for butt welding are 2.0,2.5 and 3.0 mm, with wire separations of about
8 mm.
 Depending on the desired result, the wires may be arranged side by side or one behind the other.

4. Twin Submerged Arc Welding
For twin-wire welding, two wires are connected to the same power source.
A standard SAW machine is equipped with double drive rolls and contact tips
suitable for feeding two wires simultaneously.
It produces considerably higher deposition rates than the conventional single-wire
process using large diameter wires.
Very high welding speeds can be achieved in fillet welding, but are also used
successfully for butt welding.

5. Schematic Diagram of Twin SAW

6. Tandem twin SAW
 For higher deposition rates, it can be obtained when tandem
welding is combined with twin wires.
 The tandem twin process is simply a combination of tandem and
twin-wire welding.
 It can use a combination of DC(+)/AC or AC/AC for greater
deposition rate.

7.  A tandem twin welding head is shown in Figure.
 With the use of 4x2.5 mm diameter, wires
deposition rates of up to 38 kg/h can be achieved.
 The process can be used in joints that allows
accessibility for the equipment, e.g.
circumferential welding in wind tower fabrication

8. Parallel twin wire Series twin wire
Twin- wire SAW having two versions:
 I) Twin-wire parallel Power
 II) Twin-wire series power

9. Twin-wire parallel power
 Two electrodes are fed at the same rate through a
common tip
 The current from the single power source being split
between them
 The electrode also share the drive motor and control
of equipment and therefore carry identical arc
voltage.
 Electrode dia: 1.6 to 3.2 mm
 Spacing between them: 8 to 16 mm
 DC power source with constant voltage type used
Fig: Twin arcs of same polarity in action

10. Twin-wire series power
 Main advantage of this system is high deposition rate
and minimum dilution with base metal
 Two welding heads are used with a single DC or AC
power source
 AC used for ferrous metals;
 DC used for non-ferrous metals
 The output power cable is connected to one welding
head and return power cable is connected to other
welding head.
Fig: Two-wire SA series connection

11. Comparison between different SAW

13. Comparison between single-wire and twin-wire welding
The performance parameters shown in the table below are based on the performance of the wire
feed motor, and not on basic welding characteristics.
TYPE OF WIRE
DIAMETER
(mm)
AREA
(mm2
)
WELDING CURRENT
(A) max.
DEPOSTION RATE
(kg/h)
SINGLE WIRE
3.0 7.06 650 8.0
4.0 12.56 850 11.5
5.0 19.62 1100 14.5
TWIN WIRE
2.0 6.28 1000 14.0
2.5 9.81 1200 17.0
3.0 14.13 1500 21.0

14. WELD SYSTEM
G or L
(mm)
WIRE SIZE
(mm)
Amps. Volts
STICKOUT
(mm)
TRAVEL
SPEED
(mm/sec)
DEPOSITE
RATE
(kg/hr)
Single
Electrode
4.8 4.8 1000+ 35 32 7 13.2
Twin
Electrode
5.5 2 *2 1250- 44 32 13 30
Single
Electrode
8 4 575- 34 25.4 9 9.5
Twin
Electrode
8 2 * 2 850- 32 25.4 17 17
Single
Electrode
12.5 4.8 950+ 36 32 5 13
Twin
Electrode
12.5 2 * 2 1000- 42 32 11 22

15. WELD SYSTEM
WIRE SIZE
(mm)
Amps. Volts
STICKOUT
(mm)
TRAVEL
Single
Electrode
3.2 550+ 27 19 28
Twin
Electrode
1.6 * 2 850+ 27 19 63
Single
Electrode
4 600+ 29 19 18
Twin
Electrode
2 * 2 950+ 29 19 30
Single
Electrode
3.2 575+ 30 19 30
Twin
Electrode
1.6 * 2 925+ 26 16 55

16. Application of twin arc system

17. BIBLIOGRAPHY
http://www.thefabricator.com/article/arcwelding/improving-productivity-with-submerged-arc-
welding