Preparation is the key to
producing quality weld-ments with the gas metal-arc welding process. As in GTA welding,
the equipment is expensive; therefore, you should make every effort to follow the
manufac-turer’s instruction manuals when preparing to use GMA welding equipment.
Joints
For the most part, the same joint designs recom-mended for other arc welding processes can
be used for gas metal-arc welding. There are some minor modifications that should be
considered due to the welding characteristics of the GMA process. Since the arc in GMA
welding is more penetrating and narrower than the arc for shielded metal-arc welding,
groove joints can have smaller root faces and root openings. Also, since the nozzle does
not have to be placed within the groove, less beveling of the plates is required. GMA
welding can actually lower material costs, since you use less weld metal in the joint.
Equipment
The following suggestions are general and can be applied to any GMA welding operation:
Check all hose and cable connections to make sure they are in good condition and are
properly connected.
Check to see that the nozzle is clean and the
correct size for the particular wire diameter used.
Make sure that the guide tube is clean and that
the wire is properly threaded through the gun.
Determine the correct wire-feed speed and adjust
the feeder control accordingly. During welding, the wire-speed rate may have to be varied
to correct for too little or too much heat input.
Make sure the shielding gas and water coolant
sources are on and adjusted properly.
Check the wire stick-out.
Published
by SweetHaven Publishing Services
Based upon a text provided by the U.S. Navy
