Heat Resistant & Cr-Mo

E8018-B8 Cr-Mo Welding Electrode for P9 and T9 Steel

E8018-B8 is a low-hydrogen Cr-Mo SMAW electrode for 9Cr-1Mo steels, including ASTM A335 P9 and ASTM A213 T9. It is used for high-temperature piping, boilers, pressure equipment, refinery and petrochemical applications where weld-metal compatibility with the 9Cr-1Mo base-metal system is required.

E8018-B8 for P9, T9 and 9Cr-1Mo Steel

When the base material is P9, T9 or another 9Cr-1Mo steel, E8018-B8 is the relevant AWS electrode classification to consider. It is commonly used with:

ASTM A335 P9/P9b pipe

ASTM A213 T9/T9b tube

ASTM A387 Grade 9 plate

ASTM A182 F9 forgings

ASTM A217 C12 castings

Similar 9Cr-1Mo Cr-Mo steels

Typical applications include boiler components, superheaters, steam piping, refinery equipment, petrochemical process systems and high-temperature pressure equipment.

Related procurement searches include P9 welding electrode, T9 welding electrode, 9Cr-1Mo welding electrode, 9Cr-1Mo welding rod and P9 welding consumable.

E8018-B8 Chemical Composition and AWS Classification

AWS classification requirements for undiluted weld metal are:

Element	Requirement, wt.%
C	0.05–0.10
Mn	≤1.00
Si	≤0.90
P	≤0.03
S	≤0.03
Ni	≤0.40
Cr	8.00–10.50
Mo	0.85–1.20

The 8–10.5% Cr and 0.85–1.20% Mo ranges define the principal 9Cr-1Mo alloy system of E8018-B8.

These are AWS classification limits rather than guaranteed chemistry for every commercial electrode. Actual deposited chemistry should be confirmed through the manufacturer's TDS or MTC.

E8018-B8 is also associated with the former E505 classification designation.

Mechanical Requirements

AWS A5.5/A5.5M E8018-B8 minimum weld-metal requirements include:

Property	AWS Minimum
Tensile Strength	≥550 MPa (80 ksi)
Yield Strength	≥460 MPa (67 ksi)
Elongation	≥19%

Actual mechanical properties depend on electrode formulation, welding parameters and post-weld heat treatment.

Welding Parameters for E8018-B8

E8018-B8 is a basic low-hydrogen SMAW electrode. AC or DCEP/DC+ may be available depending on the product. Final polarity and current should follow the supplied TDS and qualified WPS.

Electrode Diameter	Typical Current
2.5 mm	60–100 A
3.2 mm	90–140 A
4.0 mm	130–190 A
5.0 mm	180–240 A

These are commercial reference ranges, not AWS mandatory welding parameters.

Preheat and PWHT

P9/T9 welding requires controlled preheat, interpass temperature and PWHT for weld quality and hydrogen-cracking control.

A common commercial reference is:

Preheat/interpass: approximately 200–250°C

PWHT: approximately 740°C, often around 1 hour

Final conditions depend on material thickness, joint design, applicable construction code and qualified WPS.

E8018-B8 vs E9018-B9: Which Electrode for P9 or P91?

The base-metal grade should determine the Cr-Mo consumable:

Electrode	Typical Base Material	Alloy System
E8018-B6	P5 / T5	5Cr-0.5Mo
E8018-B8	P9 / T9	9Cr-1Mo
E9018-B9	P91 / T91	9Cr-1Mo-V-Nb
E9018-B92	P92 / T92	9Cr-2W-Mo-V-Nb-N

Although E8018-B8 and E9018-B9 both contain approximately 9% chromium, they are not interchangeable consumables. E8018-B8 is associated with conventional P9/T9 9Cr-1Mo steel, while P91/T91 requires the appropriate Grade 91 consumable system.

Classification and Supply

AWS: A5.5/A5.5M E8018-B8 ASME: SFA-5.5 E8018-B8, when certified UNS: W50418 Former Classification: E505 Process: SMAW Electrode Type: Basic low-hydrogen covered electrode Typical Sizes: 2.5, 3.2, 4.0 and 5.0 mm

GD WELD supplies E8018-B8 Cr-Mo welding electrodes for P9, T9 and similar 9Cr-1Mo steels. Available sizes, TDS, MTC, packaging and project-specific certification can be confirmed according to procurement requirements.

FAQ

What steel is E8018-B8 used for?

E8018-B8 is primarily used for 9Cr-1Mo steels, including ASTM A335 P9, A213 T9 and related Grade 9 materials.

Is E8018-B8 suitable for P91 steel?

No. P91/T91 requires a Grade 91 consumable system such as E9018-B9, rather than treating E8018-B8 as a direct substitute.

What is the difference between E8018-B8 and E9018-B9?

E8018-B8 is an 80 ksi 9Cr-1Mo electrode for P9/T9 steel, while E9018-B9 is a 90 ksi 9Cr-1Mo-V-Nb electrode for P91/T91 steel. Their alloy systems and welding requirements are different.

Internal Links

👉 Internal Link 1: Anchor text: E8018-B6 welding electrode for P5 steel

Link to: E8018-B6 Cr-Mo Welding Electrode

👉 Internal Link 2: Anchor text: E9018-B9 welding electrode for P91 steel

Link to: E9018-B9 / E9018-B91 Cr-Mo Welding Electrode