How to "Correctly" Grind, Cut & Prepare Tungsten Welding Electrodes (11 pages)

step i: tungsten electrode tip/flat preparation

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DIAMOND GROUND PRODUCTS

“The Tungsten Electrode Experts”

2550 Azurite Circle Newbury Park, CA 91320 PH: 805.498.3837 FX: 805.498.9347 Web:

www.DiamondGround.com

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3. STEP I: TUNGSTEN ELECTRODE TIP/FLAT PREPARATION

The shape of the tungsten electrode tip is an important process variable in gas tungsten arc welding. A
good selection for quick arc initiation and arc stability is a two percent Thoriated tungsten electrode
material with a fiat tip of the smallest diameter recommended for the current. Table 1.1 is a guide for
electrode tip preparation for a range of sizes with recommended current ranges.

During the welding operation, the accurately ground tip of a tungsten electrode is at a temperature
probably in excess of 3000 °C (5500 °F), and without a correct and consistent diameter flat at the tip of
the tungsten electrode the following problems can occur:

Pointed electrode tip drops into weld pool creating weld defect and X-ray defect.

Reduction in electrode life.

Arc instability

Change in arc voltage from one electrode to next electrode because of inconsistent tip shape.


NOTE: New electrodes and cut electrodes already
have a flat at the tip of the electrode.


















Before regrinding, a used electrode is reconditioned by diamond grinding a new fiat at the tip.

Table 1.1 - Tungsten Electrode Tip Shapes And Current Ranges

DCSP

(electrode negative)

Electrode Diameter

mm

Diameter

At Tip

inches

Included

angle,

mm

Constant

Current

inches

Pulsed

Current

degrees

Range,

A

Range,

A

1.02

0.040

0.125

0.005

12

2-15

2-25

1.02

0.040

0.25

0.010

20

5-30

5-60

1.59

0.062

0.5

0.020

25

8-50

8-100

1.59

0.062

0.8

0.030

30

10-70 10-140

2.38

0.093

0.8

0.030

35

12-90 12-180

2.38

0.093

1.1

0.045

45

15-150 15-250

3.18

0.125

1.1

0.045

60

20-200 20-300

3.18

0.125

1.5

0.060

90

25-250 25-350

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