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