Orion Pulse Arc Welding Workbook
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again will help remove the porosity. A fresh, sharp electrode will help with this process. Sometimes adding pure laser wire
will also help in removing porosity.
In general, gold welds easily. Here are some tips when working with gold:
1. Typically a sharp electrode is preferred when welding gold.
2. Gold can easily accept small or large weld spots
3. It is often typical that gold will look black surrounding the weld location. is black layer is easily removed with steam
cleaning, clean rag, or a small glass brush.
4. Gold can easily be added to almost any other metal.
5. Very interesting welding combinations are possible.
PLATINUM PT
Platinum (Pt) has a melting temperature that is similar to stainless steel, but a density that is 3 times higher. In addition,
the specific heat of (Pt) is lower by a factor of 4 than stainless steel. is means that it takes less energy to raise the
temperature of (Pt) to its melting temperature. e end result is that (Pt) is a little more difficult than stainless steel to
weld but very similar in overall behavior.
One important consideration when welding (Pt) is its high boiling temperature (3827 deg C) relative to tungsten’s melting
temperature (3410 deg C). What this means: if the tungsten electrode is contaminated with (Pt) metal the (Pt) metal may
superheat and start to boil right on the electrode. is boiling of the (Pt) will in turn melt the tungsten electrode causing it
to lose its sharp shape.
PALLADIUM PD
Palladium (Pd) is a white lustrous metal that is typically a much lower cost than platinum. Palladium is also much lighter,
having a density ½ that of platinum. It would seem that (Pd) is the perfect metal. Unfortunately, (Pd) is generally difficult to
work with and is somewhat difficult to weld. is is mainly due to palladium cracking during the welding process.
Palladium can be welded using the Orion welder, however, cracking can occur.
Palladium cracking is an especially difficult phenomenon to overcome with laser or pulse arc welding. If only one weld
spot is made, cracking will typically not occur unless the weld joint is stressed by hammering, etc. is means that welding
over porosity in a (Pd) piece can be accomplished with the Orion to help clean up the metal during the finishing process.
However, welding more than one overlapping weld will inevitably lead to cracking (laser or pulse arc welder).
Palladium cracking can be thought of as a combination of hot cracking and new weld puddle crystal structure problems.
After a weld, the molten (Pd) re-crystallizes, typically forming a large and weak metal grain structure. When welds overlap,
the new crystal structure in the last weld puddle is weak compared to the original metal. e result - a crack will start at
the edge of the new weld where it overlaps with the old weld joint as the new weld cools and is stressed. e crack will
then run along the middle of the weld puddle in the direction of the overlapping joints. is cracking is due to the stresses
created during the weld puddle cooling process as described above with hot cracking. However, this time instead of
geometry causing the cracking, a rip starts in the old crystal structure and propagates during the cooling process, much
like ripping a piece of paper. e result – (Pd) is difficult to weld successfully without breakage. Typically, single spots of
porosity can be welded and fixed but overlapping welds will crack.
ere is a welding solution that can stop this cracking process. e addition of gold fill wire to the weld joint creates a new
alloy and stronger crystal structure. e gold can discolor the weld joint. However, by welding over the joint several times
the gold will diffuse into the (Pd). Another possible solution is to use a high gold content white-gold (Pd) alloy laser wire.
SILVER AG
Silver is an interesting metal with several properties that must be considered during the welding process. First, silver is
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