The classification alone is not a procedure
Select a covered electrode from the base-metal grade, joint, thickness, position, power source, service duty, hydrogen requirements and applicable welding procedure—not habit alone.
Structural and safety-critical work requires the approved WPS, material records, relevant standard and current product data sheet.
1. Read the full classification
AWS characters describe electrode, strength class, position and coating/current characteristics. E6013 and E7018 are not simply weaker and stronger versions of the same tool.
Confirm approvals, sizes, polarity, operating range, mechanical values and redrying rules for the exact branded product.
2. Match the metal and joint duty
Unnecessarily high weld-metal strength can create mismatch; unknown, dirty or coated steel adds quality and fume hazards.
Thin sheet, hollow-section fabrication, heavy structures and pipe roots need different procedures. Joint geometry and specified weld quality remain decisive.
3. Select diameter for thickness and position
Larger electrodes usually need more current and create a larger pool. They can improve deposition on thick flat work but are harder to control on thin, vertical or overhead joints.
Start within the manufacturer's range for that diameter and adjust only inside the qualified procedure after a representative trial.
4. Check current, polarity and machine
An electrode may permit AC, DCEP, DCEN or a combination. Incorrect polarity changes arc stability and penetration.
Also verify duty cycle, leads, holder, work clamp, supply and open-circuit voltage rather than relying on nameplate amperage alone.
5. Keep low-hydrogen electrodes dry
Moisture pickup in low-hydrogen coatings can increase hydrogen-related cracking risk. Lincoln Electric specifies controlled holding for opened EXX18 products; ESAB documents protection from intact vacuum packs.
Never apply one household-oven recipe to every electrode family. Follow the exact manufacturer's temperature, time and exposure limits.
6. Make storage traceable
Keep sealed packs dry, clean, raised and protected; rotate stock and retain class and lot identity. Use holding ovens and portable quivers when the procedure requires them.
Do not mix electrode families under unsuitable conditions or issue cracked, wet, rusty or unidentified rods for critical work.
7. Control safety and trials
Plan shade, PPE, fume extraction, electrical safety and fire control. Coated metals and confined spaces need specific assessment.
Trial welds help set the process, but surface appearance cannot prove internal soundness; use qualified inspection where required.
Ordering checklist
Provide:
- Base-metal grade and thickness
- Joint, position and service
- WPS, standard and approvals
- Electrode class, product and diameter
- AC/DC, polarity and current range
- Hydrogen or toughness requirements
- Package, lot and certificate needs
- Holding and redrying arrangements