Orion Pulse Arc Welding Workbook
20
Pulse Arc Welding: Warping
In some specialized applications, precise positioning of the workpiece relative to a model is very important. However,
during the melting process the weld pool will expand and shrink asymmetrically, meaning that the expansion during
melting is less than the shrinkage during cooling. is asymmetric expansion can warp the workpiece.
e warping can be used to one’s advantage if done correctly. Often the user can simply observe the natural warp in the
workpiece and place welds to warp the part back into proper alignment. Even if warping is not desired there are steps to
avoid this problem.
To do this, start with lower Energy settings. is will minimize the initial warping as you stabilize the workpiece. Always
alternate sides during the welding process – several welds in a row on one side can exaggerate the warping, while
alternating welds will pull the part back and forth eliminating most warping. After the smaller stabilizing welds have been
placed you can turn up the energy and make the larger welds - alternating sides as done with the lower Energy welds.
Pulse Arc Welding: Weld Cleaning
For many applications the weld joint will require very little preparation. Keep the weld area clean and free from debris.
Remember that finger oils, etc. will cause blackening around the weld spot. is blackening can easily be wiped away with a
clean rag or taken off with a glass brush (one is included with your Orion system), sand blaster or steam cleaner.
During the welding process small amounts of metal will be vaporized from the weld joint and can be deposited elsewhere
on the workpiece. Typically, this thin film of metal will look black and can easily be cleaned off with a glass brush, ultrasonic
cleaner, etc. If the welds themselves look black or discolored, it may be an indication of oxidation and can come as a result
of too little or too much argon gas flow. If the part is too hot, some metals will readily react with oxygen to form oxide
layers. If gas flow is insufficient the weld spot may be poorly covered and oxygen may be present during the weld. On the
other hand, if the protective gas flow is too high, the gas may exit the stylus nozzle in a turbulent state. When the gas flow
is turbulent it will “grab” oxygen and other atmospheric gases and bring them inside the protective argon gas shield. is
will also lead to the molten weld puddle being exposed to oxygen.
PROTECTIVE GAS RULES OF THUMB
1. 5 - 10 PSI is a good shielding gas rate
2. e shorter the electrode is, the less gas flow is necessary
3. Gas flow may need to be increased if the electrode is lengthened.
Any discolorations that shows in titanium is an indication of poor shield gas coverage. For this reason it may be helpful to
practice on titanium to make sure your gas flow is correct. Adjust your gas to ensure no discoloration in a small titanium
weld spot. is will give you confidence of proper argon shielding for other materials.
Chapter 5: Metals
Weldability of Common Metals
One very important aspect of Pulse Arc welding is a working knowledge of material properties. is knowledge will help
you understand why various metals will react differently during the welding process. Shown below is a table of properties
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