A633 Gr.EのSMAW (low-hydrogen)用予熱 — 1-1/2" to 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.

On pressure vessel plate, E7018 is the standard manual electrode for nozzle welds, manhole reinforcements, and repair welding. ASME Section IX procedure qualifications typically require all-weld-metal tensile and guided bend tests. Rod moisture control is critical in vessel fabrication because vessel codes impose stricter hydrogen limits than structural codes.

A633 Gr.E

ASTM A633 Grade E is the highest-strength grade in this specification with 60 ksi minimum yield and 80 ksi minimum tensile strength (for plates up to 4”). Produced as normalized and tempered plate, it provides exceptional notch toughness with CVN testing at -60°F (15 ft-lbs transverse). Its higher strength level places it in Category C of Table 5.11, with correspondingly higher preheat requirements than the A/C/D grades. The quenched-and-tempered condition means carbon content is higher (0.22% max) with controlled manganese (1.15-1.50%) and silicon (0.15-0.50%), producing a CE-IIW of approximately 0.44-0.50. Like all Q&T steels, maximum interpass temperature must be respected to avoid degrading the tempered microstructure in the heat-affected zone during multi-pass welding.

A633 Gr.EとSMAW-LHでこの予熱が必要な理由

Highest-strength A633 grade at 60 ksi yield requiring Category C preheat. 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 225°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.

A633 Gr.Eの代表的な適用例

Found in heavy-duty crane runway girders for steel mills, offshore jacket legs, polar Class vessels, cold-region bridge main members, large-span roof trusses in Arctic facilities, and load-bearing elements in LNG terminal structures. A633 Gr.E combines 60 ksi yield with excellent low-temperature toughness (CVN testing at -60°F), making it suitable for primary structural members in environments where both high static loads and extreme cold coincide. Procurement lead times for A633 Gr.E plate can be 12-16 weeks due to limited domestic production, and plate availability above 2" thickness may require international sourcing. Repair welding requires the same preheat procedures as original fabrication to maintain the guaranteed toughness properties. Filler metal selection must provide tensile matching (80 ksi minimum) and cold-temperature CVN values that equal or exceed the base metal specification. Weld mockups for offshore and LNG applications typically undergo CTOD or wide-plate testing.

1-1/2" to 2-1/2"で予熱が重要な理由

Heavy plate with significant restraint and thermal mass — preheat is critical to maintain slow cooling for hydrogen escape.

SMAW (low-hydrogen)と1-1/2" to 2-1/2"における他の鋼材

A633 Gr.E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。

A633 Gr.E溶接ガイド