TIGBook_Chpt11.pdf

XI. Tables

Table 1

Types of Tungsten Electrodes

AWS

Type of

Color

Available

Classification

Tungsten (Alloy)

Code

Finish*

Remarks

EWP

Pure

Green

Cleaned

Provides good arc stability for AC welding.

and ground

Reasonably good resistance to contamination.

Lowest current carrying capacity. Least

expensive. Maintains a clean balled end.

EWCe-2

Ceria

Orange

Cleaned

Similar performance to thoriated tungsten.

CeO 2

and ground

Easy arc starting, good arc stability,

1.8% to 2.2%

long life. Possible nonradioactive

replacement for thoria.

EWLa-1

Lanthana

Black

Cleaned

Similar performance to thoriated tungsten.

La 2 O 3

and ground

Easy arc starting, good arc stability,

0.9% to 1.2%

long life, high current capacity. Possible

nonradioactive replacement for thoria.

EWLa-1.5

Lanthana

Gold

Cleaned

Similar performance to thoriated tungsten.

La 2 O 3

and ground

Easy arc starting, good arc stability,

1.3% to 1.7%

long life, high current capacity. Possible

nonradioactive replacement for thoria.

EWLa-2

Lanthana

Blue

Cleaned

Similar performance to thoriated tungsten.

La 2 O 3

and ground

Easy arc starting, good arc stability,

1.8% to 2.2%

long life, high current capacity. Possible

nonradioactive replacement for thoria.

EWTh-1

Thoria

Yellow

Cleaned

Easier arc starting. Higher current capacity.

ThO 2

and ground

Greater arc stability. High resistance to

0.8% to 1.2%

weld pool contamination. Difficult to maintain

balled end on AC.

EWTh-2

Thoria

Red

Cleaned

Easier arc starting. Higher current capacity.

ThO 2

and ground

Greater arc stability. High resistance to

1.7% to 2.2%

weld pool contamination. Difficult to maintain

balled end on AC.

EWZr-1

Zirconia

Brown

Cleaned

Excellent for AC welding due to favorable

ZrO 2

and ground

retention of balled end, high resistance to

0.15% to 0.40%

contamination, and good arc starting.

Preferred when tungsten contamination

of weld is intolerable.

EWG

Specify

Gray

Contains other rare earths or a combination

of oxides.

*Clean finish designates electrodes that are chemically cleaned and etched. Ground finish designates electrodes

with a centerless ground finish to provide maximum smoothness and consistency.

Centerless ground tungsten electrodes are used where minimum resistance loss at the collet-electrode contact

point is desired.

Table 2

Typical Current Ranges for Tungsten Electrodes*

Direct Current,

Alternating Current,

DCEN

70% Penetration

(50/50) Balanced

Wave A

Gas Cup

Ceriated

Tungsten

Inside

Thoriated

Diameter

Lanthanated

Pure

Lanthanated

Pure

Lanthanated

.040

#5 (3/8 in)

15 – 80

20 – 60

15 – 80

10 – 30

20 – 60

.060 (1/16 in)

#5 (3/8 in)

70 – 150

50 – 100

70 – 150

30 – 80

60 – 120

.093 (3/32 in)

#8 (1/2 in)

150 – 250

100 – 160

140 – 235

0 – 130

100 – 180

.125 (1/8 in)

#8 (1/2 in)

250 – 400

150 – 200

225 – 325

100 – 180

160 – 250

*All values are based on the use of Argon as a shielding gas. Other current values may be employed depending on the

shielding gas, type of equipment, and application.

DCEN = Direct Current Electrode Negative (Straight Polarity)

Table 3

Recommended Types of Current, Tungsten Electrodes and

Shielding Gases for Welding Different Metals 1

Types of Metal

Thickness

Type of Current

Electrode 2

Shielding Gas

Aluminum

All

Pure or zirconium

Argon or argon-helium

All

AC Advanced

Lanthanated, cerium

Argon or argon-helium

Squarewave

thoriated

over 1/4"

DCEN

Lanthanated, cerium

100% Helium

thoriated

Copper,

All

DCEN

Lanthanated, cerium

Helium

copper alloys

thoriated

Magnesium alloys

All

Pure or zirconium

Argon

All

AC Advanced

Lanthanated, cerium

Argon

Squarewave

thoriated

Nickel, nickel alloys

All

DCEN

Lanthanated, cerium

Argon, argon-helium,

thoriated

argon-hydrogen

(5% max)

Plain carbon,

All

DCEN

Lanthanated, cerium

Argon or argon-helium

low-alloy steels

thoriated

Stainless steel

All

DCEN

Lanthanated, cerium

Argon or argon-helium

thoriated

Titanium, zirconium,

All

DCEN

Lanthanated, cerium

Argon

hafnium 3

thoriated

Refractory Metals 3

All

DCEN

Lanthanated, cerium

Argon

thoriated

These recommendations are general guidelines based on methods commonly used in industry.

Where thoriated electrodes are recommended, lanthanated, ceriated or rare earth containing electrodes should

be used.

A glove box is often required to prevent atmospheric contamination.

Table 4

AWS Specifications for Filler Metals, Shielding Gases and Electrodes

Suitable for Gas Tungsten Arc Welding

Specification Number

Title

A 5.7

Copper and Copper Alloy Bare Welding Rods and Electrodes

A5.9

Stainless Steel Bare Welding Rods and Electrodes

A 5.10

Aluminum and Aluminum Alloy Welding Rods and Bare Electrodes

A 5.12

Tungsten and Tungsten Alloy Electrodes

A 5.13

Surfacing Welding Rods and Electrodes

A 5.14

Nickel and Nickel Alloy Bare Welding Rods and Electrodes

A 5.16

Titanium and Titanium Alloy Bare Welding Rods and Electrodes

A 5.18

Carbon Steel Filler Metals for Gas Shielded Arc Welding

A 5.19

Magnesium-Alloy Welding Rods and Bare Electrodes

A 5.21

Composite Surfacing Welding Rods and Electrodes

A 5.24

Zirconium and Zirconium Alloy Bare Welding Rods and Electrodes

A 5.28

Low Alloy Steel Filler Metal for Gas Shielded Arc Welding

A 5.30

Consumable Inserts

A 5.32

Welding Shielding Gases

Table 5

Welding Position Designations

Plate Welds

Groove Welds

1G Flat position

2G Horizontal position

3G Vertical position

4G Overhead position

Fillet Welds

1F Flat position

2F Horizontal position

3F Vertical position

4F Overhead position

Pipe Welds

Groove Welds

1G Flat position, pipe axis horizontal and rotated

2G Horizontal position, pipe axis vertical

5G Multiple positions, (overhead, vertical and flat) pipe axis horizontal and is not rotated (fixed)

6G Multiple positions, (overhead, vertical and horizontal) pipe axis in inclined 45 ˚ from horizontal

and is not rotated (fixed)

6GR Multiple positions, (overhead, vertical and horizontal) pipe axis in inclined 45 ˚ from horizontal

and is not rotated (fixed), with restriction ring

Fillet Welds

Flat position, pipe axis is 45 ˚ from the horizontal and the pipe is rotated

Horizontal position, pipe axis is vertical

2FR

Horizontal position, weld pipe axis is horizontal and the pipe is rotated

Overhead position, pipe axis is vertical

Multiple positions, (overhead, vertical and horizontal) pipe axis is horizontal and is not rotated

Multiple positions, (overhead, vertical and flat) pipe axis is 45 ˚ from horizontal and is not rotated

Table 6

Welding Process Comparison Based on Quality and Economics

All Positions

GTAW

GMAW

SMAW

Applications

Carbon steel plate (over 3/16")

Carbon steel sheet (to 3/16")

Carbon steel structural

Carbon steel pipe — 3" IPS and under

Carbon steel pipe — over 4" IPS

Stainless steel plate (over 3/16")

Stainless steel sheet (to 3/16")

Stainless steel pipe — 3" IPS and under

Stainless steel pipe — over 4" IPS

Aluminum plate (over 3/16")

Aluminum sheet (to 3/16")

Aluminum structural

Aluminum pipe — 3" IPS and under

Aluminum pipe ” over 4" IPS

Nickel and nickel alloy sheet

Nickel and nickel alloy tubing

Nickel and nickel alloy pipe — 3" IPS and under

Nickel and nickel alloy pipe — over 4" IPS

Reflective metals, titanium—sheet, tubing, and pipe

Refractory metals, TA and Cb — sheet, tubing

GTAW — Gas Tungsten Arc (TIG)

GMAW — Gas Metal Arc (MIG)

SMAW — Shielded Metal Arc (Stick)

E — Excellent

G — Good

F—Fair

NR — Not recommended on basis of cost, usability, or quality.

Table 7

Cost Information

Approximate

Average Gas and

Relative

Weld Process

Equipment Cost

Power Cost Per Hour

Labor Cost

GTAW

$1,500 – 10,000

7.00

Medium

GMAW

$2,000 – 10,000

8.00

Low

SMAW

$500 – 2,000

1.50

Low/Medium

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