E8018-B8 Welding Electrode Supplier in Mumbai, India
Nicorex Alloys, operating from Mumbai, is an ISO 9001 and ISO 14001 certified supplier and stockist of E8018-B8 welding electrodes in all standard diameters. We provide these welding electrodes as classified under AWS A5.5 and ASME SFA 5.5.
Where lower chromium-molybdenum consumables reach their oxidation and creep limits above 550°C, this electrode takes over. E8018-B8 is a basic-coated, iron-powder, low-hydrogen covered electrode that deposits 9% chromium and 1% molybdenum weld metal for service temperatures up to 600°C, with oxidation resistance extending to 700°C. This 9Cr-1Mo SMAW electrode is also recognised by the superseded E505 designation (AWS A5.4-81) and trade names such as 9-chrome welding rod. The weld deposit contains 8.0–10.5% Cr and 0.85–1.20% Mo, with carbon controlled at 0.05–0.10%. After PWHT at 740°C for 1 hour, all-weld-metal delivers a minimum tensile strength of 550 MPa (80 ksi), yield strength of 460 MPa (67 ksi), and elongation of 19%. The extra chromium content provides creep rupture strength up to 600°C and resistance to mineral oil attack, making it commonly specified for 9Cr-1Mo steels in petrochemical cracking units and coker heater tubing.
Available diameters are 2.5, 3.15, 4.0, and 5.0 mm in electrode lengths of 350–450 mm, packed in hermetically sealed cans (2.5 kg and 5.0 kg). Polarity is DCEP (recommended) or AC, with all-position capability. Base metals joined include ASME P-No. 5B Group 2 steels: A335 P9, A213 T9, A182 F9, A387 Grade 9, and A217 C12. Key industries include petroleum refining, power generation, high-pressure hydrogen service, and chemical processing.
E8018-B8 Electrode Specifications & Technical Data
| AWS Classification | E8018-B8 |
|---|---|
| ASME SFA Standard | SFA 5.5 |
| UNS Number | W50418 |
| Former Classification | E505-15 / E505-16 / E505-18 (AWS A5.4-81, superseded) |
| Welding Process | SMAW (Stick Welding) |
| Electrode Coating | Basic, low-hydrogen, iron-powder (EXX18 type) |
| Current / Polarity | DCEP (recommended) or AC |
| Welding Positions | All positions (F, V-up, OH, H) |
| Available Diameters | 2.5, 3.15, 4.0, 5.0 mm |
| Electrode Length | 350 mm (2.5–3.15 mm) / 450 mm (4.0–5.0 mm) |
Understanding the AWS E8018-B8 Electrode Designation
| Designator | Technical Meaning |
|---|---|
| E | Electrode -covered consumable for SMAW |
| 80 | Minimum tensile strength: 80 ksi (550 MPa) after PWHT |
| 1 | All-position welding capability (1G, 2G, 3G, 4G) |
| 8 | Low-hydrogen potassium coating with iron powder; AC and DCEP |
| B6 | Weld deposit: nominal 5% Cr, 0.5% Mo (formerly classified as E502) |
Chemical Composition of E8018-B8 Weld Deposit (%)
| Element | Carbon (C) | Manganese (Mn) | Silicon (Si) | Chromium (Cr) | Molybdenum (Mo) | Nickel (Ni) | Phosphorus (P) | Sulfur (S) |
|---|---|---|---|---|---|---|---|---|
| AWS A5.5 Spec Range | 0.05–0.10% | 1.00% max | 0.90% max | 8.00–10.50% | 0.85–1.20% | 0.40% max | 0.03% max | 0.03% max |
| Typical Value | 0.059% | 0.519% | 0.207% | 8.122% | 0.897% | 0.087% | 0.015% | 0.008% |
Mechanical Properties of E8018-B8 All-Weld-Metal
| Property | Tensile Strength | Yield Strength (0.2%) | Elongation (2 in / L=5d) | Charpy V-Notch Impact | Hardness (as-welded) | Hardness (after PWHT) |
|---|---|---|---|---|---|---|
| AWS A5.5 Minimum | ≥550 MPa (80 ksi) | ≥460 MPa (67 ksi) | ≥19% | Not specified | Not specified | Per code limits |
| Typical (As-Welded) | 703 MPa (101,900 psi) | 623 MPa (90,300 psi) | 21% | Not reported | >400 HV | — |
| Typical (After PWHT) | ~663 MPa (96 ksi) | ~525 MPa (76 ksi) | ~25% | Project-specific | — | ≤241 HB (ASME B31.3) |
Base Metal Compatibility & P-Number Matrix for E8018-B8
| ASME P-No. | ASTM Grades | Product Forms |
|---|---|---|
| P-5B Group 2 | A335 P9 | Seamless pipe |
| P-5B Group 2 | A213 T9 | Boiler/superheater tube |
| P-5B Group 2 | A182 F9 | Forged fittings, flanges |
| P-5B Group 2 | A387 Grade 9 Cl.1/2 | Pressure vessel plate |
| P-5B Group 2 | A217 C12 | Castings |
| P-5B Group 2 | A369 FP9, A426 CP9 | Forged/centrifugally cast pipe |
| P-5B Group 2 | A199 T9, A200 T9 | Condenser/heat exchanger tube |
| Joint Combination | Recommended Filler | Notes |
|---|---|---|
| P-5B Gr.2 (9Cr) to P-5B Gr.1 (5Cr) | E8018-B8 or E8018-B6 | Use B8 if service >550°C |
| P-5B Gr.2 (9Cr) to P-4 (P11, 1.25Cr) | E8018-B8 | Overmatches P11 side |
| P-5B Gr.2 (9Cr) to P-8 (austenitic SS) | E309L-16 or ENiCrFe-2 | Ni-based filler for cyclic thermal service |
| P-5B Gr.2 (9Cr) to P-1 (carbon steel) | E8018-B8 | Overmatches carbon steel side |
Recommended Welding Parameters for E8018-B8
| Diameter (mm) | Length (mm) | Current Range (A) | Polarity |
|---|---|---|---|
| 2.5 | 350 | 60–90 | DC(+) |
| 3.15 | 350 | 90–130 | DC(+) |
| 4.0 | 350/450 | 130–170 | DC(+) or AC |
| 5.0 | 450 | 170–230 | DC(+) or AC |
Maintain a short arc length (approximately equal to core wire diameter); 9Cr weld metal picks up atmospheric nitrogen, which degrades toughness. Use stringer beads; avoid weaving beyond 3× electrode diameter. Preheat: 200–300°C (392–572°F) minimum for P9 base metal, increasing to 250–300°C for walls above 12.5 mm. Interpass: 200–300°C; do not exceed 300°C.
After the final pass, apply post-heat at 300–350°C for a minimum of 2 hours, then slow-cool under insulation before PWHT. PWHT: 720–760°C (1328–1400°F), minimum 1 hour per 25 mm of thickness. Post-PWHT hardness must be ≤241 HB per ASME B31.3.
Get AWS Class E8018-B8 Welding Electrode at Competitive Prices
Industrial Welding Applications of E8018-B8 Coated Electrode
- Delayed coker heater tubes, vacuum distillation transfer lines, and crude unit. E8018-B8 is the mandatory consumable for these P9-grade piping circuits.
- A213 T9 superheater and reheater tubes operating at 560–600°C in coal-fired and gas-fired power stations require E8018-B8 to match base metal creep performance. Boiler headers and attemperator connections fabricated from A387 Grade 9 plate also rely on this electrode.
- Hydrogen reformer outlet piping, hydrocracker reactor shells, and hydrogen loop piping in ammonia plants
- Heat exchangers, reactor vessels, and transfer piping in synthetic fuel plants and coal liquefaction facilities.
Storage, Handling & Re-Drying Procedures for E8018-B8
E8018-B8 deposits fully martensitic 9Cr-1Mo weld metal that is extremely susceptible to hydrogen-induced cold cracking. Strict electrode storage is non-negotiable.
Keep electrodes in factory-sealed hermetic containers until immediately before use. Store sealed containers in a dry environment at a minimum 5°C above ambient dew point. After opening, transfer all electrodes to a heated holding oven at 120–175°C (250–350°F). If exposed to the atmosphere for more than 2 hours, re-bake at 370–430°C (700–800°F) for a minimum of 1 hour.
Maximum re-baking cycles: 2 (stricter than 5Cr electrodes due to 9Cr martensite sensitivity). Exposure from holding oven: Exposure times should follow project welding procedures and applicable fabrication codes. Issue to welders in heated quivers. For humid climates (coastal refineries, offshore), use only fresh sealed stock. Record electrode issue and return times as part of weld quality documentation.
How to Order E8018-B8 Electrodes from Nicorex Alloys
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AWS Classification - E8018-B8 or E8018-B8L (low-carbon) per AWS A5.5
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Electrode Diameter(s) - 2.5, 3.15, 4.0, 5.0 mm
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Quantity - In kg or number of sealed cans
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Packaging - Hermetically sealed cans (2.5 kg / 5.0 kg) or vacuum-packed
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Hydrogen Designation - H4R if project requires ≤4 ml/100g
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Third-Party Approvals - DNV, ABS, Lloyds, Bureau Veritas, BHEL, PDIL (specify all)
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Test Certificate - MTC 3.1 per EN 10204; specify additional CVN or diffusible hydrogen tests
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Matching Consumable Set - ER80S-B8 TIG/MIG wire if needed
- Delivery Address & Timeline - Delivery address & timeline
Complete 9Cr-1Mo consumable sets (E8018-B8 + ER80S-B8 TIG rod + ER80S-B8 MIG wire) keep weld deposit chemistry consistent across SMAW, GTAW, and GMAW processes on the same project.
Frequently Asked Questions
What is the Difference Between E8018-B8 and E8018-B6 Welding Electrodes?
E8018-B8 deposits 9Cr-1Mo weld metal (A-Number A-5) while E8018-B6 deposits 5Cr-0.5Mo (A-Number A-4). E8018-B8 has a maximum service temperature of 600°C versus 550°C for E8018-B6, and provides oxidation resistance to 700°C. E8018-B8 is used for P9 steels (A335 P9, A213 T9); E8018-B6 is for P5 steels.
Can E8018-B8 be Used to Weld P91 (9Cr-1Mo-V-Nb) Steel?
No. P91 steel (ASME P-No. 15E) requires E9015-B9 or E9018-B9 electrodes with vanadium (0.15–0.30%) and niobium (0.02–0.10%). E8018-B8 lacks these elements, so the weld deposit won’t develop MX carbonitride precipitates essential for P91 creep performance.
What Makes E8018-B8 Weld Deposits Resistant to Mineral Oil Attack?
The 8–10.5% chromium in E8018-B8 weld metal forms a stable chromium oxide scale that resists naphthenic acids and mineral oil breakdown products at elevated temperatures.
Can E8018-B8 Be Used for Welding P11 to P9 Dissimilar Joints?
Yes. E8018-B8 is recommended for P-4 (P11, 1.25Cr-0.5Mo) to P-5B Group 2 (P9, 9Cr-1Mo) dissimilar joints. The 9Cr deposit overmatches P11 in oxidation resistance and creep strength.
When Not to Use E8018-B8 Welding Electrode?
Do not use E8018-B8 for P91 (9Cr-1Mo-V-Nb) or P92 (9Cr-2W) steels: these CSEF steels require E9015-B9 or E9015-B92 with vanadium and niobium additions. Do not use for open-root pipe welding without back-purge. Never weld with E8018-B8 without PWHT.