Weld Electrode Reference — E60XX, E70XX, E80XX Classifications
Complete reference for AWS D1.1 compliant SMAW (stick) electrode classifications. Match electrode strength to base metal yield strength, understand preheat requirements, and select appropriate electrodes for structural applications.
Quick Reference
| Electrode | Min Tensile | Min Yield | Typical Base Metal |
|---|---|---|---|
| E60XX | 414 MPa (60 ksi) | 345 MPa (50 ksi) | A36 (250 MPa) |
| E70XX | 483 MPa (70 ksi) | 400 MPa (58 ksi) | A992 (345 MPa) |
| E80XX | 550 MPa (80 ksi) | 460 MPa (67 ksi) | A572 Gr. 65 (450 MPa) |
| E90XX | 620 MPa (90 ksi) | 530 MPa (77 ksi) | Quenched & Tempered (≥600 MPa) |
| E48XX | 480 MPa | 400 MPa | AS/NZS 300PLUS (300 MPa) |
| E55XX | 550 MPa | 460 MPa | AS/NZS 350PLUS (350 MPa) |
Electrode Classification System
AWS A5.1 specifies electrode classification format: EXXXX-XX
- E = Electrode (SMAW)
- XXXX = Minimum tensile strength in ksi (× 6.89 for MPa)
- XX = Coating and position capability
Example: E7018
- E70 = Minimum 70 ksi (483 MPa) tensile strength
- 1 = Iron powder low-hydrogen coating
- 8 = All-position capability (flat, horizontal, overhead, vertical-down)
Strength Matching Guidelines
AWS D1.1 permits using electrodes with strength greater than or equal to base metal. For fillet welds loaded in shear, weld strength is governed by electrode tensile strength.
Matching Rules
- A36 (250 MPa / 36 ksi) → Use E60XX electrode
- A992 (345 MPa / 50 ksi) → Use E70XX electrode
- A572 Gr. 65 (450 MPa / 65 ksi) → Use E80XX electrode
- Quenched & Tempered (≥600 MPa / ≥87 ksi) → Use E90XX+ electrode
Overmatch vs Undermatch
- Overmatch: Weld metal strength exceeds base metal. Preferred for most structural applications.
- Undermatch: Weld metal strength is lower than base metal. Acceptable for fillet welds with engineering approval.
Base Metals Reference
| Grade | Yield (Fy) | Recommended Electrode | Notes |
|---|---|---|---|
| A36 | 250 MPa (36 ksi) | E60XX | General purpose carbon steel |
| A992 | 345 MPa (50 ksi) | E70XX | Standard structural steel |
| A572 Gr. 50 | 345 MPa (50 ksi) | E70XX | High-strength low-alloy |
| A572 Gr. 65 | 450 MPa (65 ksi) | E80XX | High-strength low-alloy columns |
| S355 (EN 10025) | 355 MPa | E70XX | European structural steel |
| S460 (EN 10025) | 460 MPa | E80XX | High-strength European steel |
| 300PLUS (AS/NZS 3679.1) | 300 MPa | E48XX | Australian grade 300 |
| 350PLUS (AS/NZS 3679.1) | 350 MPa | E55XX | Australian grade 350 |
Preheat Requirements
Minimum preheat temperatures per AWS D1.1 for structural steel welding.
| Thickness | Min Preheat | Notes |
|---|---|---|
| ≤ 20 mm (≤ 3/4") | 10°C (50°F) | No preheat required (ambient) |
| 20-40 mm (3/4" - 1-1/2") | 10°C (50°F) | No preheat required (ambient) |
| 40-65 mm (1-1/2" - 2-1/2") | 66°C (150°F) | A36, A992 minimum |
| 65-100 mm (2-1/2" - 4") | 107°C (225°F) | Preheat recommended |
| > 100 mm (> 4") | 149°C (300°F) | Consider PWHT for critical joints |
Note: These are minimum requirements. For low-hydrogen electrodes (E7018-H4), lower preheat may be acceptable. High-restraint joints may require higher temperatures.
Electrode Selection by Application
| Application | Recommended Electrode | Notes |
|---|---|---|
| General structural (A992, A36) | E7018 | Low-hydrogen, excellent ductility |
| Heavy structural (A572 Gr. 65+) | E8018-C1 | Higher strength, low-hydrogen |
| Field welding (damp conditions) | E7018-H4 | Very low hydrogen (H4) |
| Horizontal position only | E7024 | Fast freezing, flat/horizontal |
| All-position, thin material | E6013 | Smooth bead, easy to use |
Common SMAW Electrodes
E60XX Series
- E6010: Deep penetration, flat/horizontal only
- E6011: Similar to E6010, good for tight gaps
- E6013: Smooth bead, easy slag removal, all-position
- E6018: Low-hydrogen, general purpose, ductile welds
E70XX Series (Most Common)
- E7014: Iron powder, faster deposition, flat/horizontal fillet
- E7018: Low-hydrogen, all-position, most common structural
- E7024: Fast-freezing, horizontal/flat fillet welds
- E7028: Low-hydrogen, all-position, smoother arc
E80XX Series (High-Strength)
- E8018-C1: Low-hydrogen, high strength for A572 Gr. 65
- E8018-C3: Low-hydrogen, high strength, deeper penetration
Charpy V-Notch Requirements
Electrode classification may include Charpy V-notch toughness requirements for fracture-critical applications:
- E7018: 27J minimum at -29°C (-20°F) for certain applications
- E8018: Specified per AWS A5.1
Toughness requirements vary by application and code. Seismic applications may require stricter toughness.
Frequently Asked Questions
Q: Can I use E70XX electrode for A36 base metal? Yes. Using E70XX (overmatch) on A36 is acceptable and often preferred for improved weld ductility.
Q: What does "XX" in E60XX mean? The "XX" indicates electrode coating and position capability. Example: E7018 has iron powder low-hydrogen coating (1) and all-position rating (8).
Q: What is low-hydrogen electrode? Low-hydrogen electrodes (designated -H4, -H8) contain very little diffusible hydrogen, reducing risk of delayed cracking in high-strength steels.
Q: When is preheat required? Preheat is required for thick sections, high-strength steels, high-restraint joints, and low ambient temperatures. See table above for minimum AWS D1.1 requirements.
Q: Can I mix metric (E48XX) and imperial (E70XX) electrodes? E48XX is metric equivalent of E70XX (48 = 480 MPa ≈ 70 ksi). The classification systems are equivalent: E48XX ≈ E70XX, E55XX ≈ E80XX.
Run This Calculation
→ Welded Connections Calculator — fillet weld capacity, weld group analysis, and directional strength increase per AISC 360, AS 4100, EN 1993, CSA S16.
See Also
- Fillet Weld Size Chart — Minimum and Maximum per AISC
- Weld Symbol Chart — AWS A2.4 Welding Symbols Reference
- Minimum Fillet Weld Size Table — AISC J2.4 & AS 4100
- Fillet Weld Size Selection — AISC 360 Table J2.4
- Steel Connection Design — Bolted and Welded Limit States
- Steel Fy & Fu Reference — Yield and Tensile Strength by Grade
- steel grade tensile strengths for electrode matching
- Connection Checks
- Fatigue Design
- Weld Group Properties
- Weld Joint Types
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