A1066 Gr.60/65 Preheat for SAW — over 2-1/2"

SAW (Submerged Arc Welding)

SAW submerges the arc beneath granular flux for highest deposition rates, flat/horizontal only. Category B in Table 5.11.

SAW on high-strength plate requires careful selection of wire-flux combinations to meet both tensile matching and toughness requirements. F8A4-EA2 or similar high-performance combinations serve Category C steels. Heat input control is particularly important on TMCP grades because SAW naturally deposits high heat input due to the deeply penetrating arc.

SAW Tips for High-Strength and TMCP Steels

For A1066 Grades 60/65 HSLA plate (60–65 ksi yield, Category C or H8 Category E), SAW with F8A4-EA2 provides tensile matching at 80 ksi minimum. H8 Category E path (50°F up to 1", 120°F above) requires H8-certified flux — verify lot certificate, not just wire. On offshore monopile transition piece seams (plate to 4" thick), tandem SAW with two wires.

Typical values for reference — always verify against your approved WPS and electrode manufacturer data.

Why SAW for A1066 Gr.60/65 at over 2-1/2"

Why SAW for A1066 Gr.60/65 at over 2-1/2"? SAW delivers 15-40 lb/hr deposition — the highest deposition rate among available processes. Position capability: flat and horizontal only. Suitability: shop only.

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 SAW

Higher-strength 60/65 ksi HSLA plate for bridges with H8 preheat option. The higher strength level of this steel places it in Category C of Table 5.11, which carries elevated preheat requirements compared to Category B grades. At 300°F minimum with SAW, the submerged arc process with granular flux produces controlled hydrogen levels, with flux condition being the primary variable, but the preheat must still ensure the cooling rate stays slow enough to prevent hydrogen-induced cracking in this higher-hardenability material.

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 over 2-1/2"

The heaviest sections demand the highest preheat in Table 5.11. Multi-pass sequences require maintaining interpass temperature throughout.

Category C Preheat for A1066 Gr.60/65

Category C in Table 5.11 applies to higher-strength steels where the combination of hardenability and residual stress requires elevated preheat. For A1066 Gr.60/65 at over 2-1/2", the 300°F minimum preheat slows the weld cooling rate to prevent formation of crack-susceptible martensite in the heat-affected zone. Maintaining interpass temperature at or above this minimum is especially critical for multi-pass welds on restrained joints.

Other Steels with SAW at over 2-1/2"

A1066 Gr.60/65 with SAW

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