Short Circuit: Wrong for the Job

A large Sterling, Colorado based fabricator of non ASME tanks, skids and mobile liquid transporters for the oil & gas industry allowed General Air to audit their welding practices in search of cost reduction ideas. During the fact finding PE walk through process, a number of problems surfaced including the unnecessary use of multiple welding shielding gases, excessive solid wire short circuit spatter, and mediocre bead appearance (which was particularly apparent after the part was painted). Will pulsed MIG transfer be their answer?

Excessive, costly grinding was employed to remove spatter as well as flatten the weld crown common to “ropey” short circuit welds. Determining what % spatter reduction produces what % increase in arc on time is difficult. So, after converting to just one gas mix, we decided to minimize spatter as much as possible and then be very conservative in our cost savings estimate.

Pulsed MIG Transfer: The Solution

The end-user was using both 75Ar/25CO2 for short circuit transfer and 98Ar/2O2 for axial spray transfer on circumferential welds. Changing to 85Ar/15CO2 allowed utilization of both transfers while reducing cylinder inventory and, thus, rental cost.

Next, we demoed .035 solid wire in pulse transfer (on a Lincoln PowerWave C300) to prove reduced spatter level, increased deposition rate (vs short circuit transfer) and optimal out of position capability. The resultant weld beads were markedly improved and the end-user almost immediately converted their shielding gas to 85/15 and purchased the PowerWave.  The end-user, now a General Air customer, is happy.

Success Highlights: $98,840 in Annual Savings

• 90% Spatter Reduction
• 50% Cylinder Inventory Reduction
• Improved Bead Appearance
• Inverter Energy Savings

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