Orion Pulse Arc Welding Workbook
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often come with a coating of zinc. e zinc coating will cause the metal to appear more white or lustrous than typical steel.
As discussed above, welding on zinc will cause many issues to consider. e zinc will evaporate quickly from the weld
area causing a black coat to spread to the surrounding metal (including the welding stylus). e zinc evaporation may also
cause strange weld behavior, etc.
For best results select a low carbon steel without a zinc coating. Make sure the steel is free from other contaminates
such as rust or oil. Remember that if using the Orion to produce welds in very thick pieces the weld joint may need to be
prepared as discussed previously.
HIGH CARBON STEELS SPRING STEEL / TOOL STEEL
High carbon steel welds easily but may become brittle after the welding process. To avoid weld failure the part must be
heat treated after the welding process.
COBALT CHROME ALLOYS
Cobalt Chrome is very sensitive to oxygen contamination. If there is insufficient argon coverage or oxygen present in the
argon gas this alloy will crack. Once oxygen embrittlement has occurred the weld area must be removed (via grinding etc)
to prevent future cracking over the same area.
COPPER
Copper is one of the more difficult alloys to weld because of its high heat capacity and high thermal conductivity. ese
factors make it even more difficult to weld than silver. Copper also requires more energy than silver for the weld to take
place (about 30% more). in copper, however, welds very easily and lower energy is typically sufficient to produce very
strong welds. For thicker copper similar techniques as those employed to weld silver must be used.
BRASS
Brass is a material that contains a large amount of zinc - 30 -37% zinc by composition. e remaining material is copper.
As discussed previously, zinc is a hard metal to pulse arc weld or resistance weld because of its low melting and boiling
temperature (420 deg C, 907 deg C).
During the melting process the low temperature zinc evaporates/boils out of the brass alloy.
For low energies this simply coats the surrounding material in a black zinc film that can easily be removed with a glass
brush.
For larger pulse arc weld energies the black coat can cover larger areas and porosity can develop at the weld location as
zinc boils from the weld.
JOINING DIFFERENT METALS
Welding different metals together will produce a new alloy at the weld location. e new alloy will have different properties
(although in many cases similar properties) to the base metals. Some metals combine well, forming a strong and useful
new alloy. Other metal combinations are weak and brittle.
Helpful Hints for Combining Different Metals
1. Check the new alloy strength with scrap material to ensure the joint will turn out as expected.
2. You may need to weld over the joint location several times to get complete mixing of the weld pool and a uniform new
alloy. In most cases this is not necessary for a strong joint and the first weld will be sufficient.
3. Some material combinations may benefit from a third metal at the joint which forms a better/stronger alloy with the
two primary metals.
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