R-Tech TIG 500 AC/DC, Operating Instructions Manual

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6
Use of DCEN
For a given diameter of tungsten electrode,
higher amperage can be used with straight
polarity. Straight polarity is used mainly for
welding:
• Carbon steels
• Stainless steels
• Copper alloys
The increased amperage provides:
• Deeper penetration
• Increased welding speed
• A narrower, deeper, weld bead.
DCEP
The DCEP (reverse polarity) are different from
the DCEN in following ways:
• High heat is produced on the electrode rather
on the base metal.
• The heat melts the tungsten electrode tip.
• The base metal remains relatively cool
compared to sing straight polarity.
• Relatively shallow penetration is obtained.
• An electrode whose diameter is too large will
reduce visibility and increase arc instability.
Use of DCEP
• Intense heat means a larger diameter of
electrode must be used with DCEP.
• Maximum welding amperage should be
relatively low (approximately six times lower
than with DCEN).
Alternating Current with High-Frequency
Welding with alternating current
Welding with alternating current combines both
direct-current characteristics:
• In the positive phase, cleaning action occurs in
the weld puddle.
• During the negative phase, heat is
concentrated in the weld puddle.
• The above causes increased penetration.