Heat Resistant & Cr-Mo

E8018-B6 Cr-Mo Welding Electrode for P5 and T5 Steel

E8018-B6 is a low-hydrogen Cr-Mo welding electrode for 5Cr-0.5Mo heat-resistant steel. It is mainly used for ASTM A335 P5, A213 T5 and similar Cr-Mo steels in refinery piping, petrochemical equipment, boilers, pressure vessels and high-temperature process systems. Classified under AWS A5.5/A5.5M E8018-B6, the electrode produces weld metal with a controlled chromium-molybdenum alloy system for matching 5Cr-0.5Mo steel. E502 is an older classification designation associated with this electrode ty

E8018-B6 for P5 and T5 Steel

E8018-B6 welding electrode is commonly selected for:

ASTM A335 P5/P5b pipe

ASTM A213 T5/T5b tube

ASTM A387 Grade 5 plate

ASTM A182 F5/F5a forgings

ASTM A217 C5 castings

Similar 5Cr-0.5Mo creep-resistant steels

The P5 welding electrode and T5 welding electrode search terms are closely related to E8018-B6 because the consumable is designed for steels with a matching Cr-Mo alloy system.

Typical applications include oil refineries, petrochemical plants, boilers, heat exchangers, pressure vessels and high-temperature piping. Commercial E8018-B6 products are also used where resistance to hydrogen attack, sulfidation and elevated-temperature service is required.

E8018-B6 Chemical Composition

AWS classification requirements for undiluted weld metal include:

Element	AWS Requirement, wt.%
C	0.05–0.10
Mn	≤1.00
Si	≤0.90
P	≤0.03
S	≤0.03
Ni	≤0.40
Cr	4.00–6.00
Mo	0.45–0.65

The 4–6% Cr and 0.45–0.65% Mo alloy system is the defining chemistry of E8018-B6. These are classification limits, not a guaranteed analysis for every commercial electrode. Actual deposited chemistry should be confirmed by the manufacturer's TDS/MTC.

Mechanical Properties of E8018-B6

AWS A5.5/A5.5M minimum requirements include:

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

Actual weld-metal results can be higher depending on electrode formulation, welding conditions and PWHT. Commercial E8018-B6 products commonly report values above these classification minimums.

Welding P5/T5 Steel with E8018-B6

E8018-B6 is a basic low-hydrogen SMAW electrode. AC or DCEP/DC+ may be specified depending on the product design.

Typical Welding Current

Electrode Diameter	Typical Current
2.5 mm	60–100 A
3.2 mm	80–140 A
4.0 mm	120–190 A
5.0 mm	150–240 A

These are commercial reference ranges rather than AWS mandatory welding parameters. Manufacturer recommendations vary by electrode size and formulation.

Preheat and PWHT

P5/T5 welding requires controlled preheat, interpass temperature and post-weld heat treatment (PWHT) to manage hydrogen cracking and weld-metal/HAZ properties.

Commercial procedures may use approximately 200–300°C preheat/interpass temperature and PWHT around 740–750°C, depending on material thickness, applicable code and qualified WPS. For example, commercial E8018-B6 products specify preheat around 250°C and PWHT around 740–750°C.

These are procedure or manufacturer references, not universal AWS requirements.

E8018-B6 vs E8018-B2 and E9018-B3

Choosing a Cr-Mo electrode by strength class alone is not enough. The consumable should also match the base-metal alloy system.

	E8018-B2	E8018-B6	E9018-B3
Typical steel	P11 / T11	P5 / T5	P22 / T22
Main alloy system	Cr-Mo	5Cr-0.5Mo	2.25Cr-1Mo
Strength class	80 ksi	80 ksi	90 ksi
Main application	1.25Cr-0.5Mo steel	5Cr-0.5Mo steel	2.25Cr-1Mo steel

E8018-B6 should be selected when the specified base material requires a 5Cr-0.5Mo consumable. E8018-B2 and E9018-B3 should not be treated as automatic substitutes. Industry product lineups likewise distinguish E8018-B6 specifically for Grade 5 / 5Cr steel.

Applications and Supply

E8018-B6 welding electrodes are commonly used for:

P5 and T5 Cr-Mo pipe welding

Oil refinery piping

Petrochemical process equipment

Boilers and heat exchangers

Pressure vessels

High-temperature Cr-Mo fabrication and repair

AWS: A5.5/A5.5M E8018-B6 ASME: SFA-5.5 E8018-B6, when certified 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-B6 Cr-Mo welding electrodes for P5/T5 and similar 5Cr-0.5Mo steels. TDS, MTC, electrode sizes, packaging and project-specific certification can be confirmed according to customer requirements.