Preheat Heat Input Fillet Weld Size Deposition Rate Carbon Equivalent
AWS D1.1:2025 · Table 5.11 · Category C

A633 Gr.E Preheat for SAW — 3/4" to 1-1/2"

Minimum preheat and interpass temperature for A633 Gr.E welded with SAW at 3/4" to 1-1/2" thickness, per AWS D1.1:2025 Table 5.11.

Minimum Preheat & Interpass Temperature
150°F / 65°C
Category C
Low-hydrogen SMAW, SAW, GMAW, or FCAW process (higher-strength steels)
AWS D1.1:2025 Table 5.11, §5.7
Reference tool. Verify against project-applicable edition and Engineer-approved WPS.

SAW (Submerged Arc Welding)

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

For pressure vessel longitudinal and circumferential seams, SAW is the primary process. Tandem or multi-wire configurations on specialized manipulators achieve consistent quality over seam lengths exceeding 40 feet. Flux basicity index per ASME Section II Part C determines the mechanical properties of the weld deposit.

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.

Why This Preheat for A633 Gr.E with SAW

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 150°F minimum with SAW, 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.

Typical Applications for A633 Gr.E

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.

Why Preheat Matters at 3/4" to 1-1/2"

Preheat climbs at this range as thicker material slows heat dissipation, trapping hydrogen at crack-susceptible grain boundaries.

Category C Preheat for A633 Gr.E

Category C in Table 5.11 applies to higher-strength steels where the combination of hardenability and residual stress requires elevated preheat. For A633 Gr.E at 3/4" to 1-1/2", the 150°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 3/4" to 1-1/2"

SteelCategoryPreheat
A36B50°F (10°C)
A53 Gr.BB50°F (10°C)
A106 Gr.BB50°F (10°C)
A709 HPS70WC150°F (65°C)

Try Different Combinations

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

What is the minimum preheat for A633 Gr.E with SAW at 3/4" to 1-1/2"?
For A633 Gr.E welded with SAW at 3/4" to 1-1/2" thickness, the minimum preheat temperature is 150°F (65°C) per AWS D1.1:2025 Table 5.11, Category C. This is also the minimum interpass temperature — the joint must not cool below 150°F between passes.
What Table 5.11 category applies to A633 Gr.E with SAW?
A633 Gr.E welded with SAW falls under Category C in AWS D1.1:2025 Table 5.11. Low-hydrogen SMAW, SAW, GMAW, or FCAW process (higher-strength steels). At 3/4" to 1-1/2" thickness, this category requires a minimum preheat of 150°F (65°C).
Why is preheat 150°F for A633 Gr.E at 3/4" to 1-1/2"?
The 150°F preheat for A633 Gr.E at 3/4" to 1-1/2" with SAW reflects the combination of the steel's hardenability and the increased restraint at this thickness. Higher preheat slows the cooling rate in the heat-affected zone, giving diffusible hydrogen more time to escape before the steel transforms to a crack-susceptible microstructure.
Why does preheat increase at 3/4 inch?
Below 3/4”, the thin section sheds heat and hydrogen quickly. Above 3/4”, the thicker material acts as a heat sink, cooling the HAZ faster and trapping diffusible hydrogen at crack-susceptible grain boundaries. Table 5.11 raises the minimum preheat at this threshold to slow the cooling rate and give hydrogen more time to diffuse out of the weld zone.

D1.1:2025 reference data. Not affiliated with AWS.