A913 Gr.80のSMAW-LH (H4)用予熱 — over 2-1/2"

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.

A913 Gr.80

ASTM A913 Grade 80 (80 ksi yield, 95 ksi minimum tensile) is the highest-strength TMCP shape specification in D1.1, produced exclusively by the QST process. It requires H4-certified consumables (the strictest hydrogen control at ≤4 mL/100g deposited weld metal per AWS A4.3) and falls exclusively under Category G, which has four thickness-dependent preheat tiers (32°F up to 3/4”, 50°F up to 1-1/2”, 150°F up to 2-1/2”, 225°F above). No other hydrogen designation, standard low-hydrogen, or non-low-hydrogen SMAW is prequalified for this grade under Table 5.11. The H4 requirement limits the available consumable pool significantly — only select electrode classifications carry the H4 designator. A913 Gr.80 availability is limited to heavy W14 column sections from a small number of domestic and international mills, with procurement lead times typically 16-24 weeks.

A913 Gr.80とSMAW-LHでこの予熱が必要な理由

Highest-strength 80 ksi TMCP shape requiring H4 consumables exclusively. This steel requires H4-certified consumables — the strictest hydrogen control in Table 5.11 at no more than 4 mL diffusible hydrogen per 100g. At 225°F with SMAW-LH, the four thickness-dependent preheat tiers in Category G reflect the balance between the steel's 80 ksi yield strength and the exceptional hydrogen control provided by H4 certification. No other hydrogen designation is prequalified for this grade.

A913 Gr.80の代表的な適用例

Reserved for the most demanding column applications in super-tall structures, typically interior gravity columns carrying 50+ stories of tributary load. A913 Gr.80 allows W14 sections to replace built-up box columns, simplifying connections and reducing fabrication cost while maintaining equivalent axial capacity. Every weld on this grade demands verified H4 consumables and documented preheat compliance — no exceptions or substitutions are permitted under Table 5.11. Column splice CJP welds require UT inspection per D1.1 Table 8.2. Only a limited number of domestic mills produce A913 Gr.80 shapes, with lead times of 16-24 weeks for non-stock sizes. The H4 consumable requirement eliminates most standard electrode inventory and requires dedicated electrode orders for each project. Fabricators must establish verified H4 supply chains before bidding Gr.80 column work, as H4-designated electrodes are not stocked by most welding distributors. Rejected consumable certifications can delay erection schedules by weeks.

over 2-1/2"で予熱が重要な理由

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

A913 Gr.80とSMAW-LH (H4)

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。

A913 Gr.80溶接ガイド