A1066 Gr.60/65 Preheat for FCAW (H8) — up to 1"

FCAW (Flux Cored Arc Welding)

FCAW uses tubular flux-cored wire, available gas-shielded (E71T-1) or self-shielded (E71T-8) for field work. Category B in Table 5.11.

High-strength FCAW wires such as E81T1-K2 and E91T1-K2 provide tensile matching for Category C steels. The flux system in these wires is formulated for low diffusible hydrogen, often meeting H8 supplementary limits when tested per AWS A4.3. Wire storage requires climate-controlled conditions similar to SMAW electrodes to prevent moisture absorption.

A1066 Gr.60/65

ASTM A1066 Grades 60 (60 ksi yield, 75 ksi tensile) and 65 (65 ksi yield, 80 ksi tensile) are higher-strength low-alloy plates used in bridges and structural applications requiring both strength and toughness at sub-zero temperatures. They fall under Category C for standard low-hydrogen processes, reflecting their higher CE-IIW of approximately 0.44-0.50, and qualify for Category E reduced preheat (50°F up to 1”, 120°F above 1”) with H8-certified consumables. The dual-path preheat option (Category C standard vs. Category E with H8) gives fabricators economic flexibility — choosing H8 consumables adds a small material premium but can save significant preheating time and fuel cost on thick-section joints. Both grades are produced in plate thicknesses up to 6" and require ASTM supplementary toughness requirements for bridge or offshore service.

Why This Preheat for A1066 Gr.60/65 with FCAW

Higher-strength 60/65 ksi HSLA plate for bridges with H8 preheat option. With H8-certified FCAW consumables, this steel qualifies for Category E in Table 5.11. The 50°F preheat at this thickness reflects the balance between the reduced hydrogen from H8 certification and the steel's strength level. Category E uses a 1-inch thickness breakpoint rather than the standard 3/4-inch, recognizing that H8 consumables provide a wider safe margin at moderate thicknesses.

Typical Applications for A1066 Gr.60/65

Specified for long-span bridge plate girder flanges, cable-stayed deck plates, offshore wind monopile transition pieces, heavy-wall tubular joints in jacket structures, and demanding structural applications requiring both 60+ ksi yield and sub-zero toughness. The H8 preheat reduction to Category E (50°F up to 1", 120°F above 1") makes these grades economically competitive for heavy plate fabrication where heating thick sections adds hours to the welding cycle. Plate thicknesses in offshore monopile transition pieces can reach 4" or more, with individual circumferential seams requiring sustained preheating over several hours. The combination of high strength, toughness, and H8 preheat eligibility positions A1066 Gr.60/65 as a premium alternative to conventional plate grades in demanding offshore environments. Filler metal selection must achieve tensile matching (80+ ksi) while meeting CVN requirements at the service temperature — typically -4°F to -40°F for North Sea and US Gulf offshore installations.

Why Preheat Matters at up to 1"

Moderate thickness where hydrogen diffusion is still efficient. H8 consumables on eligible steels may reduce the preheat requirement.

Other Steels with FCAW (H8) at up to 1"

A1066 Gr.60/65 with FCAW (H8)

Try Different Combinations

Use the interactive preheat calculator to look up any steel, process, and thickness combination from D1.1:2025 Table 5.11.

A1066 Gr.60/65 Welding Guides