2. Chapter 11
SMAW: Electrodes
Goodheart-Willcox Publisher

3. Learning Objectives Identify carbon and low alloy SMAW electrodes.
List six purposes of an electrode covering.
Interpret the AWS electrode identification system.
Determine the trial amperage of a welding machine using the rule-of-thumb method.
Select an electrode to meet the requirements of a weld.
Identify two means of storing electrodes.

4. Introduction SMAW electrode properties
Solid, round metal wires
Low-carbon steel
Covered (coated)
Melting electrode provides filler material
Electrode selection depends on several factors

5. AWS Electrode Specifications

6. Electrode Coverings Also called flux coverings Purposes
Create shield around arc and weld
Create flux to clean impurities
Create hard slag covering to protect weld while cooling
Improve mechanical and chemical properties of weld
Provide filler metal
Determine current type and polarity in electrode

7. Effects of Certain Flux Coverings
Metallic salts
Make weld stronger, more corrosion resistant, or more ductile
Iron powder
Electrode deposits more filler metal into weld in given length of time
Low hydrogen electrodes
Deposit minimum amount of hydrogen into weld
Help prevent weakened welds

8. Electrode Sizes Lengths Diameters Diameters (cont.) 9″ (229 mm)

9. AWS Electrode Identification System for SMAW Electrodes
Goodheart-Willcox Publisher

10. Recommended Polarity
Last two numerals of electrode designation indicate recommended electrical polarity

11. AWS Electrode Suffixes
Suffix indicates that alloys have been added to electrode

12. Low Hydrogen Electron Covering Compositions

13. Electrode Amperage Requirements
Electrode diameter determines amperage required
Larger diameter needs higher amperage
Manufacturer’s guide provides guidelines
Trial amperage
Rule-of-thumb method

14. Rule-of-Thumb Method Steps
Determine base amperage for the electrode
Determine difference between 1/8″ (3.2 mm) electrode and electrode to be used
Convert the fractional difference from step 2 to equivalent fraction with 32 in denominator
Multiply the number of 32nds by 30A

15. Rule-of-Thumb Method Steps (Cont.)
Calculate the trial amperage
If the electrode diameter is larger than 1/8″, add the answer from step 4 to the base amperage in step 1
If the electrode diameter is smaller than 1/8″, subtract the answer from step 4 to the base amperage in step 1

16. Welding Procedure Specification (WPS)
Used for commercial jobs
Outlines how weld is to be made
Lists diameter and type of AWS electrode
Specifies type of current and current setting or range
Not needed for most fabrication, repair, and craft welding
Welder or shop owner selects electrode

17. Factors for Selecting Electrodes
Type of metal
Metal thickness
Groove design
Joint alignment
Available welding current
Welder skill
Welding position
Deposition rate
Depth of penetration
Weld bead finish
Additional metal properties

18. Type of Metal Determine tensile strength of base metal
Tensile strength of electrode should be as strong as that of base metal

19. Metal Thickness Consider number of passes needed for metal thickness
Weld passes no more than 1/4″ (6.4 mm) thick
Wider weld beads needed for thicker metal
Electrodes that do not penetrate deeply work well with thin metal
E6012
E6013

20. Groove Design Wide V-groove joint
Small-diameter electrode for root pass
Larger electrodes for filler and cover passes
Narrow bevel-, V-, J-, and U-groove joints
Smaller-diameter electrodes for root pass and next few passes

21. Joint Alignment
Poorly designed or assembled joints may have large openings
Use electrodes designed to span large root openings
E6012
E6013
E7014

22. Welder Skill Highly skilled welders Less-skilled welders
May use large-diameter electrode and high amperage
Achieve proper penetration
Less-skilled welders
Select electrode that allows proper penetration with their level of skill

23. Welding Position
Flat
All electrodes
Overhead
EXX1X
EXX4X

24. Deposition Rate Amount of filler deposited per unit time
Measured in pounds or kilograms per hour
Achieving high deposition rate
Larger electrode diameter
Higher amperage
DCEP

25. Depth of Penetration Good penetration on thick metal
Deeper penetration
E6010
E6011

26. Weld Bead Finish When good appearance is needed
When appearance is not as important
E6010

27. Additional Metal Properties
Alloying elements
Improve strength
Provide corrosion resistance
Add other desirable characteristics
Low hydrogen electrode coatings
Low in moisture
Low in hydrogen

28. Care of Electrodes Keep in shipping containers until used
Keep away from moisture
Moisture contains hydrogen (H2)
Hydrogen weakens the weld
Do not bend electrodes

29. Care of Low Hydrogen Electrodes
Store in electrode drying oven
Use within specified time after removing from oven
Goodheart-Willcox Publisher

30. Electrode Dispenser Provides temporary storage
Protects electrodes while out of oven