Gas Metal Arc Welding GMAW

5 Essentials of Arc Welding Arc Length Travel Speed Electrode Angle Electrode Machine Setting

GMAW Machine Settings Machine setting depends on thickness of metal. Voltage (see chart on machine) Wire speed (see chart on machine) Shielding gas (100% Carbon Dioxide = 25cfh) Protects weld area from contamination. Non-Inert = CO2 Inert = Argon Gas Drift: Windy conditions move the shielding gas away from the weld area resulting in a poor weld.

Electrode (wire) Type of wire depends on base metal. Mild steel base metal = mild steel wire. Various sizes (.023”, .030”, .035”, .045”) All machines in our shop are set up with .030” mild steel wire.

Electrode Angle Work angle (front to back) Flat welds = 90 T – Joint = 45 Travel angle (right to left) Always 90

Travel Speed Resulting weld should be 3/16” – ¼” wide.

Arc Length Stickout: Length of wire sticking out from the welding tip. Should be around ¼”. Listen carefully to your weld, should have a constant sizzle, no cracking or popping.

Welding Gun When you pull the trigger on the welding gun 3 things happen simultaneously: Shielding gas starts Wire-feed starts Arc starts Parts: Nozzle: Directs shielding gas to weld area/ Tip: Directs the wire to weld area. Distributor: Disperses shielding gas. Trigger: Starts and stops welding operation.

GMAW Related Terms Cold lap: Non-penetrating weld; weld sits on top of or overlaps base metal. Causes: Improper machine setting, low heat, improper arc length(stickout).

GMAW Safety Equipment/Tools Welding helmet Safety glasses Gloves Long sleeves Hair tied back Needle-nose pliers Wire-brush