Variations-
Metal
Transfer
Introduction
Equipment
Description
Short Arc
Welding
Power
Supply
Shielding
Gases
Globular
Transfer
Spray Arc
Welding
Cored Wire
Welding
Wire
Electrodes
Safety
Welding
Techniques
Welding
Conditions
Economics
Weld
Defects
Mig Spot
Welding
Tables

 

7 Continued on next page... Spray Arc Welding By raising the welding current and voltage still further, the metal transfer will become a true spray arc. The minimum welding current at which this occurs is called the transition current. Table 1-2 shows typical values of transition current for various filler metals and shielding gases. As seen in this table, the transition current depends on the metal wire diameter and shielding gas. However, if the shielding gas for welding carbon steel contains more than about 15% CO2 there is no transition from globular transfer to spray transfer. Figure 1-3 shows the typical fine arc column and pointed wire of the spray arc. The molten drops from the wire are very small, affording good arc stability. Short circuiting is rare. Little spatter is associated with this welding technique. Spray arc welding can produce high deposition rates of weld metal. This welding technique is generally used for joining materials 3/32 in. (2.4mm) and greater in thickness. Except when welding aluminum or copper, the spray arc process is generally restricted to welding in the flat position only because of the large weld puddle. However, mild steel can be welded out of position with this technique when small weld puddles are used; generally with a .035 in. (.89mm) or .045 in. (1.1mm) diameter wires. Figure 1-3 Spray Arc Welding Technique