DEFINITION OF SPRAY TRANSFER
KELVIN LONGDENKELVIN LONGDEN
PROCEDURES DEPARTMENTPROCEDURES DEPARTMENT
PRESENTATION OVERVIEW
Modes of metal transferModes of metal transfer Factor affecting metal transfer Factor affecting metal transfer Spray transfer dataSpray transfer data Guidelines for spray transfer Guidelines for spray transfer
MODES OF METAL TRANSFER
Short-Circuiting Transfer (GMAW-SC)Short-Circuiting Transfer (GMAW-SC) Globular Transfer (GMAW-GL)Globular Transfer (GMAW-GL) Spray Transfer (GMAW-SP)Spray Transfer (GMAW-SP) Pulsed Transfer (GMAW-P)Pulsed Transfer (GMAW-P)
SHORT-CIRCUITING TRANSFER MODE (GMAW-SC)
Repetitive short-circuits (the arc is extinguished) between the Repetitive short-circuits (the arc is extinguished) between the wire and the welding puddle. wire and the welding puddle.
The parameters are at their lowest range for the GMAW processThe parameters are at their lowest range for the GMAW process Application in all positions for thin sheet and for the root pass Application in all positions for thin sheet and for the root pass
welding of pipe. welding of pipe. Difficult to apply successfully to thicker materials because of the Difficult to apply successfully to thicker materials because of the
low values of amperage and voltage may result in fusion low values of amperage and voltage may result in fusion problems. problems.
Not prequalified.Not prequalified.
GLOBULAR TRANSFER (GMAW-GL)
Droplet transfer is nonaxial with a diameter larger that the wire Droplet transfer is nonaxial with a diameter larger that the wire
size.size. In argon-rich gases this mode of metal transfer occurs with In argon-rich gases this mode of metal transfer occurs with
parameters below the spray transition but above that for short-parameters below the spray transition but above that for short-
circuiting.circuiting. Spatter can be excessive, rough-looking beads, glass-like silica Spatter can be excessive, rough-looking beads, glass-like silica
island formations.island formations. Limited use compared to short-circuit and spray transfer modes. Limited use compared to short-circuit and spray transfer modes. Not considered prequalified. Not considered prequalified.
SPRAY TRANSFER (GMAW-SP)
Molten metal is transferred across the arc in a continuous Molten metal is transferred across the arc in a continuous stream of fine droplets.stream of fine droplets.
The arc is stable.The arc is stable. Current and voltage above critical transition values and the use Current and voltage above critical transition values and the use
of argon-rich gas mixtures. of argon-rich gas mixtures. High deposition rates and desirable fusion and penetration High deposition rates and desirable fusion and penetration
characteristics.characteristics. Considered prequalified.Considered prequalified.
PULSED TRANSFER (GMAW-P)
Periodic surges or pulses of current above the transition value Periodic surges or pulses of current above the transition value for spray transfer which causes the detachment of droplets. for spray transfer which causes the detachment of droplets.
Between the current pulses, the arc is maintained by a relatively Between the current pulses, the arc is maintained by a relatively low background current. low background current.
Average current can be well below the transition value - weld Average current can be well below the transition value - weld appearance resembling that obtained in spray transfer. appearance resembling that obtained in spray transfer.
Not prequalified Not prequalified
METAL TRANSFER ACROSS THE ARC IN GMAW
The mode of the weld metal transfer is determined by the The mode of the weld metal transfer is determined by the
following factors:following factors:
Welding currentWelding current
Electrode sizeElectrode size Electrode compositionElectrode composition Electrode stick outElectrode stick out Shielding gasShielding gas
GAS MIXTURES FOR GMAW FOR CARBON STEELS
The gas mixtures commonly used for gas metal arc welding of The gas mixtures commonly used for gas metal arc welding of carbon steel are:carbon steel are:
Argon / Oxygen - Argon / Oxygen - 98% Ar / 2% O98% Ar / 2% O22 , 95%Ar / 5 , 95%Ar / 5% O% O22
Argon / Carbon dioxide - Argon / Carbon dioxide - 90% Ar / 10% CO90% Ar / 10% CO22 , 85 , 85% Ar / 15% % Ar / 15%
COCO22 , 75 , 75% Ar / 25% CO% Ar / 25% CO22
Argon / Carbon dioxide / oxygenArgon / Carbon dioxide / oxygen - - 91% Ar / 5% CO91% Ar / 5% CO22 / 4% O / 4% O2, 2,
90% Ar / 8% CO90% Ar / 8% CO22 / 2% O / 2% O2, 2,
GMAW Gases That Produce Similar Results Group A - Lows Energy Group A - Lows Energy
MixesMixes Argon + 1-10% oxygenArgon + 1-10% oxygen Argon + 2-10% CO2Argon + 2-10% CO2 Argon + 1-10% oxygen + 2-Argon + 1-10% oxygen + 2-
10% CO210% CO2
Group B – Medium Energy Group B – Medium Energy MixesMixes
Argon + 14-20% CO2 Argon + 14-20% CO2 Argon + 1-5% oxygen + 14-Argon + 1-5% oxygen + 14-
20% CO2 20% CO2
GMAW Carbon Steel Wire (98 % Ar 2 % O2 - DC+)A vs WFS
050
100150200250300350400450500550600650700750800850900950
1000105011001150120012501300
015 30 45 60 75 90
105
120
135
150
165
180
195
210
225
240
255
270
285
300
315
330
345
360
375
390
405
420
435
450
465
480
Current (A)
WFS
(ipm
)
0.5
0.7
0.8
0.9
1.1
1.3
1.6
Spray Start
Spray Transfer Zone
GMAW Mode of Metal Transfer (.9 mm Wire 95% Ar 5% O2)
390410430450470490510530550570590610630650670690710730
24.50 25.00 25.50 26.00 26.50 27.00 27.50 28.00 28.50
Voltage (V)
WFS
(ipm
)
Non Spray Arc
Spray Arc
GMAW Mode of Metal Transfer (.9 mm wire / 95% Ar 5% O2)
235
245
255
265
275
285
295
305
315
325
335
345
355
365
24.50 25.00 25.50 26.00 26.50 27.00 27.50 28.00 28.50
Voltage (V)
Curr
ent (
A)
Non Spray Arc
Spray Arc
GMAW Mode of Metal Transfer (.9 mm Wire Ar + 15-20 % CO2)
350370390410430450470490510530550570590610630650670690710730
28.5 29 29.5 30 30.5 31 31.5 32 32.5 33 33.5 34 34.5
Voltage (V)
WFS
(ipm
)
Spray Arc
Non Spray Arc
GMAW Mode of Metal Transfer (.9 mm wire Ar + 15-20 % CO2)
200
220
240
260
280
300
320
340
360
28.5 29 29.5 30 30.5 31 31.5 32 32.5 33 33.5 34 34.5
Voltage (V)
Curr
ent (
A)
Non Spray Arc
Spray Arc
GMAW Mode of metal Transfer (1.2 mm Wire Ar + 15-20% O2)
280300320340360380400420440460480500520540560580600620640660680700720740
26.0
0
26.5
0
27.0
0
27.5
0
28.0
0
28.5
0
29.0
0
29.5
0
30.0
0
30.5
0
31.0
0
31.5
0
32.0
0
32.5
0
33.0
0
33.5
0
34.0
0
34.5
0
35.0
0
35.5
0
Voltage (V)
WFS
(ipm
)
Non Spray Arc
Spray Arc
GMAW Mode of Metal Transfer (1.2 mm Ar + 15-20% CO2)
240
260
280
300
320
340
360
380
400
420
440
460
480
27.0
0
27.5
0
28.0
0
28.5
0
29.0
0
29.5
0
30.0
0
30.5
0
31.0
0
31.5
0
32.0
0
32.5
0
33.0
0
33.5
0
34.0
0
34.5
0
35.0
0
35.5
0
36.0
0
36.5
0
Voltage (V)
Curr
ent (
A)
Non Spray Arc
Spray Arc
GMAW Mode of Metal Transfer (1.6 mm wire Ar+15 % CO2)
300
320
340
360
380
400
420
440
460
480
500
520
30.0
0
30.5
0
31.0
0
31.5
0
32.0
0
32.5
0
33.0
0
33.5
0
34.0
0
34.5
0
35.0
0
35.5
0
36.0
0
36.5
0
37.0
0
37.5
0
38.0
0
38.5
0
Voltage (V)
Curr
ent (
A)
Non Spray Arc
Spray Arc
GMAW Mode of Metal Transfer (1.6 mm Wire Ar + 15% CO2)
150170190210230250270290310330350370390410430450
30.7
5
31.2
5
31.7
5
32.2
5
32.7
5
33.2
5
33.7
5
34.2
5
34.7
5
35.2
5
35.7
5
36.2
5
36.7
5
37.2
5
37.7
5
38.2
5
38.7
5
Voltage (V)
WFS
(ipm
)
Non Spray Arc
Spray Arc
GMAW Mode of Metal Transfer (QC)0.9mm 90%Ar-10%CO2
200225250275300325350375400425450475500525550575600625650675700725
24 25 26 27 28 29 30 31 32 33
Voltage (V)
WF
S (
ipm
)
NON SPRAY SPRAY
GMAW Mode of Metal Transfer (QC)0.9mm 80%Ar - 20%CO2
300325350375400425450475500525550575600625650675700725
29.5 30 30.5 31 31.5 32 32.5 33 33.5 34
Voltage (V)
WF
S (
ipm
)
SPRAYNON SPRAY
GMAW Mode of Metal Transfer (QC)0.9mm 86%Ar-12%CO2-2%O2
200225250275300325350375400425450475500525550575600625
27.5 28 28.5 29 29.5 30 30.5
Voltage (V)
WF
S (
ipm
)
NON SPRAY
SPRAY
Spray Transfer Guidelines
Shielding Gas – Argon rich - maximum 20% CO2Shielding Gas – Argon rich - maximum 20% CO2
Welding parameters in accordance with graphsWelding parameters in accordance with graphs
Look and sound of the arcLook and sound of the arc