© COPYRIGHT 1998 THE ESAB GROUP, INC. LESSON II




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Lesson 1
The Basics of Arc Welding
Lesson 2
Common Electric
Arc Welding Processes
Lesson 3
Covered Electrodes for Welding
Mild Steels
Lesson 4
Covered Electrodes for Welding Low Alloy Steels
Lesson 5
Welding Filler Metals for Stainless Steels
Lesson 6
Carbon & Low Alloy
Steel Filler Metals -
GMAW,GTAW,SAW
Lesson 7
Flux Cored Arc Electrodes Carbon Low Alloy Steels
Lesson 8
Hardsurfacing Electrodes
Lesson 9
Estimating & Comparing Weld Metal Costs
Lesson 10
Reliability of Welding Filler Metals
2.2.2.5 While polarity affects the penetration and burn-off rate, the electrode coating also has a strong influence on arc characteristics.  Performance of individual electrodes will be discussed in succeeding lessons. 2.2.3 Electrode Holder - The electrode holder connects to the welding cable and con- ducts the welding current to the electrode.  The insulated handle is used to guide the electrode over the weld joint and feed the electrode over the weld joint and feed the electrode into the weld puddle as it is consumed.  Electrode holders are available in different sizes and are rated on their current carrying capacity. 2.2.4 Ground Clamp - The ground clamp is used to connect the ground cable to the work piece.  It may be connected directly to the work or to the table or fixture upon which the work is positioned.  Being a part of the welding circuit, the ground clamp must be capable of carrying the welding current without overheating due to electrical resistance. 2.2.5 Welding Cables - The electrode cable and the ground cable are important parts of the welding circuit.  They must be very flexible and have a tough heat-resistant insulation. Connections at the electrode holder, the ground clamp, and at the power source lugs must be soldered or well crimped to assure low electrical resistance.  The cross-sectional area of the cable must be sufficient size to carry the welding current with a minimum of voltage drop. Increasing the cable length necessitates increasing the cable diameter to lessen resistance and voltage drop.  The table in Figure 4 lists the suggested American Wire Gauge (AWG) cable size to be used for various welding currents and cable lengths. Total Cable Length (Ground Lead Plus Electrode Lead) Up to 50 ft. Up to 100 ft. Up to 250 ft. Up to 500 ft. Cable Voltage Cable Voltage Cable Voltage Cable Voltage Size Drop Size Drop Size Drop Size Drop 20 to 180 #3 1.8 #2 2.9 #1 5.7 #0 9.1 180 Amps 30 to 250 #2 1.8 #1 2.5 #0 5.0 #0 9.9 200 Amps 60 to 375 #0 1.7 #0 3.0 #00 5.9 #000 9.3 300 Amps 80 to 500 #00 1.8 #000 2.5 #0000 5.0 #0000 9.9 400 Amps 100 to 600 #00 2.0 #0000 2.5 ... ... ... 500 Amps Voltage drops indicated do not include any drop caused by poor connection, electrode holder, or work metal Welding Service Range (Amperes) Voltage Drop Figured At FIGURE 4 2.2.6 Coated Electrodes - Various types of coated electrodes are used in shielded metal arc welding.  Electrodes used for welding mild or carbon steels are quite different than those used for welding the low alloys and stainless steels.  Details on the specific types will be covered in subsequent lessons.