19
OrionWelders.com
A proper weld joint will help the weld puddle cool
uniformly. is will allow even stresses within the weld
puddle and prevent weld cracking.
Palladium and high carbon steel cracking is a special case and is difficult to overcome when 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 (or laser) to help clean up a ring 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 a new weld puddle crystal structure problem.
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 previous weld, the new puddle will be weak compared to the original metal. e result is
a crack will start at the edge of the new weld where it overlaps with the old weld joint. e crack will then run along the
middle of the weld puddle in the direction of the overlapping joints. is 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 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, with Pd, single spots of porosity can be welded and
fixed but overlapping welds will crack.
Pulse Arc Welding: Joint Preparation
Your Orion can be adjusted to a weld penetration of up to approximately 0.66 mm in depth (depending on the material).
However, deeper penetration usually also means large spot size around 1.5 to 2 mm. When deep penetration is desired but
the weld spot size needs to remain small or the workpiece thickness is very thick, additional weld joint preparation may be
necessary.
e Y joint is the simplest joint to prepare. Use
fill wire of an appropriate diameter to build up
material in the joint. Weld with no fill material for
the first pass to increase the weld penetration
into the joint. en add fill wire to build up
material in the top of the Y until the material is
flush with the top surface.
Other joint preparations like X, V, etc. are possible and the welding procedure
is similar.
To Next Page
Loading...
Need help?
General
