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

A992 Preheat for SAW — 1-1/2" to 2-1/2"

Minimum preheat and interpass temperature for A992 welded with SAW at 1-1/2" to 2-1/2" thickness, per AWS D1.1:2025 Table 5.11.

Minimum Preheat & Interpass Temperature
150°F / 65°C
Category B
Low-hydrogen SMAW, SAW, GMAW, or FCAW process
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.

SAW with F7A2-EM12K wire/flux delivers the highest deposition rates for flat-position fillet welds on building steel. Typical parameters: 500-700 amps, 28-32 volts, 18-30 IPM travel speed. Flux consumption runs approximately equal to wire consumption by weight. Unfused flux recovery and recycling systems are standard in production shops to control consumable costs.

A992

ASTM A992 (50 ksi minimum yield, 65 ksi maximum yield, 65 ksi minimum tensile) is the standard specification for W-shapes in building construction — virtually all wide-flange beams and columns in US structural steel buildings are A992. The specification was created in 1998 to address weldability concerns with earlier A36/A572 shapes by imposing tighter chemistry controls: 0.23% max carbon, 0.15% max combined V+Cb+N, and a 0.85 maximum yield-to-tensile ratio to ensure ductile behavior in seismic connections. These controls produce a typical CE-IIW of 0.38-0.44. It falls under Category B in Table 5.11, requiring low-hydrogen welding processes. Most domestic W-shapes are dual-certified A992/A572 Gr.50, with actual mill test yields typically 50-58 ksi. The controlled chemistry makes A992 the most weldable 50 ksi structural shape available.

Why This Preheat for A992 with SAW

Standard W-shape specification for virtually all US building wide-flanges. This steel is prequalified only with low-hydrogen processes under Table 5.11, which is why it appears in Category B but not Category A. The 150°F minimum preheat with SAW balances the steel's strength level and carbon equivalent against the controlled hydrogen input from the consumable. Non-low-hydrogen SMAW is not an option for this grade under D1.1 prequalified WPS.

Typical Applications for A992

The universal W-shape steel for building frames: beam-to-column moment connections, simple shear tabs, column web doubler plates, continuity plates, collector beams in lateral systems, drag struts, transfer beams, and composite deck stud rails. A992 chemistry control (max 0.23% carbon, max 0.15% V-Cb-N) was specifically designed to improve weldability over earlier A36/A572 shapes after the 1994 Northridge earthquake revealed brittle fracture problems in welded steel moment frames. Flange CJP welds in seismic moment frames are the highest-criticality joints in US building construction. The controlled yield-to-tensile ratio (max 0.85) ensures ductile behavior in seismic connections by guaranteeing sufficient strain hardening capacity. Mill test reports for A992 shapes routinely show actual yield strengths of 50-55 ksi, well above the 50 ksi minimum. The weld access hole geometry per AISC 358 is dimensioned specifically for A992 flanges to reduce stress concentrations at the CJP weld termination.

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

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

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

SteelCategoryPreheat
A36B150°F (65°C)
A633 Gr.EC225°F (110°C)
A709 HPS70WC225°F (110°C)
A710 Gr.AC225°F (110°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 A992 with SAW at 1-1/2" to 2-1/2"?
For A992 welded with SAW at 1-1/2" to 2-1/2" thickness, the minimum preheat temperature is 150°F (65°C) per AWS D1.1:2025 Table 5.11, Category B. This is also the minimum interpass temperature — the joint must not cool below 150°F between passes.
What Table 5.11 category applies to A992 with SAW?
A992 welded with SAW falls under Category B in AWS D1.1:2025 Table 5.11. Low-hydrogen SMAW, SAW, GMAW, or FCAW process. At 1-1/2" to 2-1/2" thickness, this category requires a minimum preheat of 150°F (65°C).
Why is preheat 150°F for A992 at 1-1/2" to 2-1/2"?
The 150°F preheat for A992 at 1-1/2" to 2-1/2" 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.
What happens if I skip preheat on thick plate?
Without adequate preheat on material in the 1-1/2” to 2-1/2” range, the weld HAZ cools rapidly, trapping diffusible hydrogen in a hardened microstructure. This creates conditions for hydrogen-induced cracking (also called cold cracking or delayed cracking), which may not appear until hours or days after welding. Table 5.11 preheat minimums are set to prevent this failure mode.

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