Miller Electric CST 250 VRD manual Selecting and Preparing Tungsten Electrode

SECTION 7 − SELECTING AND PREPARING

TUNGSTEN ELECTRODE

gtaw 7/97

NOTE

For additional information, see your distributor for a handbook on the Gas Tungsten Arc Welding (GTAW) process.Wear clean gloves to prevent contamination of tungsten electrode.

7-1. Selecting Tungsten Electrode

		Amperage Range - Gas Type♦ - Polarity
Electrode Diameter	DC − Argon − Electrode	DC − Argon − Electrode	AC − Argon − Using	AC − Argon − Balanced
	Negative/Straight Polarity	Positive/Reverse Polarity	High Frequency	Wave Using High Freq.
2% Thorium Alloyed
Tungsten (Red Band)
.010”	Up to 25	*	Up to 20	Up to 15
.020”	15-40	*	15-35	5-20
.040”	25-85	*	20-80	20-60
1/16”	50-160	10-20	50-150	60-120
3/32”	135-235	15-30	130-250	100-180
1/8”	250-400	25-40	225-360	160-250
5/32”	400-500	40-55	300-450	200-320
3/16”	500-750	55-80	400-500	290-390
1/4”	750-1000	80-125	600-800	340-525

♦Typical argon shielding gas flow rates are 15 to 35 cfh (cubic feet per hour).

*Not Recommended.

The figures listed are intended as a guide and are a composite of recommendations from American Welding Society (AWS) and electrode manufacturers.

7-2. Safety Information About Tungsten

Y Grinding the tungsten elec-

	trode produces dust and fly-
	ing sparks which can cause
1	injury and start fires. Use lo-
	cal exhaust (forced ventila-
	tion) at the grinder or wear an
	approved respirator. Read
	MSDS for safety information.
	Consider	using	tungsten
	containing ceria,		lanthana,
	or yttria	instead of thoria.
	Grinding dust from thoriated
2	electrodes contains low-lev-
	el radioactive		material.
	Properly dispose of grinder
	dust in an environmentally
	safe way. Wear proper face,
	hand, and body protection.
	Keep flammables away.
1	Tungsten Electrode With
	Balled End
2	Pointed Tungsten Electrode

Ref. S-0161

OM-220 812 Page 27