A1066 Gr.60/65のSMAW (low-hydrogen)用予熱 — up to 3/4"

SMAW (Low-Hydrogen)

Low-hydrogen SMAW (E7018/E7016) uses basic-coated electrodes requiring rod oven storage, assigned to Category B in Table 5.11.

For high-strength shapes and plate, E7018 provides adequate tensile match for steels up to Category C. E8018-C3 or E9018-M may be required for higher-strength steels to meet weld metal strength matching requirements. Bead sequencing on thick TMCP flanges should follow qualified WPS parameters precisely to avoid overheating the refined microstructure.

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.

A1066 Gr.60/65とSMAW-LHでこの予熱が必要な理由

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 50°F minimum with SMAW-LH, the preheat ensures the cooling rate stays slow enough to prevent hydrogen-induced cracking in this higher-hardenability material. Category C steels demand careful attention to interpass temperature control throughout the weld sequence.

A1066 Gr.60/65の代表的な適用例

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.

up to 3/4"で予熱が重要な理由

Thin material sheds heat quickly, allowing hydrogen to escape the HAZ readily — lowest preheat tier in Table 5.11.

SMAW (low-hydrogen)とup to 3/4"における他の鋼材

A1066 Gr.60/65とSMAW (low-hydrogen)

別の組み合わせを試す

インタラクティブ予熱計算機を使用して、D1.1:2025 表5.11のあらゆる鋼材・プロセス・板厚の組み合わせを検索できます。

A1066 Gr.60/65溶接ガイド