A992 Preheat for SMAW (low-hydrogen) — 1-1/2" to 2-1/2"
Per AWS D1.1:2025 Table 5.11, the minimum preheat for A992 welded with SMAW (low-hydrogen) at 1-1/2" to 2-1/2" is 150°F (65°C), Category B. Preheat below this raises hydrogen-cracking risk in the heat-affected zone; the same temperature is the minimum interpass limit maintained through the weld.
Built on AWS D1.1:2025 Table 5.11 — every value traced to the clause.
Have a preheat question? Ask Flux
SMAW (Low-Hydrogen)
Low-hydrogen SMAW (E7018/E7016) uses basic-coated electrodes requiring rod oven storage, assigned to Category B in Table 5.11.
E7018 is the default electrode for structural fillet and groove welds on common building steels. Rod ovens should hold at a minimum of 250°F per D1.1 Clause 7.3.2.1; exposure time out of the oven is limited to 4 hours maximum per Table 7.1. For overhead position, use 3/32" diameter rods to control puddle size. Vertical-up stringer beads provide the best fusion on thicker members.
Why SMAW (low-hydrogen) for A992 at 1-1/2" to 2-1/2"
Why SMAW (low-hydrogen) for A992 at 1-1/2" to 2-1/2"? SMAW (low-hydrogen) delivers 3-5 lb/hr deposition — compared to <a href="/welding/preheat-calculator/a992/saw/1-1-2-to-2-1-2-inch/">SAW</a> at 15-40 lb/hr. Position capability: all positions. Suitability: field and shop.
Filler Metal for SMAW-LH
Electrode: E7018 (AWS A5.1). Table 5.7 lists it for Group I and Group II base metals only; Groups III, IV and V take AWS A5.5 low-alloy electrodes from Table 5.7. Diameter: 1/8" (general/out-of-position), 5/32" (production), 3/16" (heavy plate flat only). Storage: 250°F rod oven minimum per D1.1 §7.3.2.1. Exposure limit: 4 hours out of oven per Table 7.1, then re-bake at 500-800°F for minimum 2 hours per §7.3.2.4 (A5.1 classification).
Typical values for reference — always verify against your approved WPS and electrode manufacturer data.
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 SMAW-LH
Standard W-shape specification for virtually all US building wide-flanges. This steel is prequalified only with low-hydrogen processes under Table 5.11. With SMAW-LH, E7018 low-hydrogen electrodes produce typically 4-8 mL/100g diffusible hydrogen under proper rod oven conditions. The 150°F minimum preheat balances the steel’s strength level and carbon equivalent against the hydrogen control provided by SMAW-LH. 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 SMAW (low-hydrogen) at 1-1/2" to 2-1/2"
| Steel | Category | Preheat |
|---|---|---|
| A1066 Gr.50 | B | 150°F (65°C) |
| A1066 Gr.60/65 | C | 225°F (110°C) |
| A1066 Gr.70 | C | 225°F (110°C) |
| A633 Gr.E | C | 225°F (110°C) |
A992 with SMAW (low-hydrogen)
Try Different Combinations
Use the interactive preheat calculator to look up any steel, process, and thickness combination from D1.1:2025 Table 5.11.
A992 Welding Guides
Primary sources
D1.1:2025 reference data. Not affiliated with AWS.
Application context
A992 in the 1-1/2 to 2-1/2 inch range with SMAW low-hydrogen typically appears in heavy-flange wide-flange shapes (W14, W36 column and beam sections) for AISC moment-frame work, plus jumbo built-up sections in transfer-girder territory and continuity-plate welds at major column-girder joints. The 150°F minimum is the AISC-tier preheat — not a token requirement.
Pre-weld notes
Stick welding at this thickness is uncommon as a primary process — most heavy-section A992 work uses FCAW or SAW for deposition rate. Where SMAW-LH applies, it is usually for fit-up correction, weld repair, or constrained-access locations on moment-frame connections where automated processes cannot reach. Three constraints sit on top of the 150°F floor: the preheat-extent rule shifts at 1-1/2 inch per Clause 7.6 (heated zone at least equal to base-metal thickness, not less than 3 inches), real preheat infrastructure is required (induction blankets, electric resistance pads), and LH electrode atmospheric exposure runs faster at the slower deposition pace of heavy-section stick welding.
What a CWI verifies
A CWI on A992 SMAW-LH heavy-section work verifies preheat through-thickness, not just surface — sampling 3-6 inches from the arc on the back side catches the through-thickness lag during heat-up. Interpass temperature held above 150°F across multi-pass deposition is verified with a contact pyrometer between pass groups. High-restraint connections in moment-frame work — column-to-girder full-penetration joints in seismic zones — may warrant the contractor specifying higher than the 150°F minimum based on the project's engineering documents.