25
24
Fig 9 AC Advanced Preparation
x = 1.5 to 4 times diameter
D
x
Fig 10 Correct Grind Direction
Fig 11 Incorrect Grind Direction
D
30°
30° x
Fig 8 Tungsten Preparation
x = 1.5 to 4 times diameter
(2 x D = 30° included angle)
Tungsten Current Ranges
Electrode
Diameter (mm)
Gas
Cup Size
DC
Current Amps
Filler Wire
Diameter (mm)
1.0
6
15-80
1.6
1.6
6
70-150
1.6-2.4
2.4
8
150-250
2.4-3.2
Safety Consideration Thoritated
Tungsten.
Thoriated Tungsten contains the
element Thorium (Th). Thorium is a
radioactive element which mainly
emits alpha particles. Alpha particles
cannot penetrate skin, or clothing,
but can be a harmful carcinogen if
released inside the digestive tract,
or lungs.
There is almost no release of
radioactive material during arcing.
There is no significant hazard in handling
and storage. The Thoria is inside the
tungsten electrode, it is enclosed in a
tungsten matrix and so there is little
radiation emitted externally.
The greatest risk of exposure is during
the grinding of the thoriated tungsten
electrodes. Care needs to be taken, to
control the dust. A dust mask should
be worn, and grinder area clean up
should be done with a vacuum cleaner.
