A36 Preheat for SMAW (non-low-hydrogen) — up to 3/4"
Per AWS D1.1:2025 Table 5.11, the minimum preheat for A36 welded with SMAW (non-low-hydrogen) at up to 3/4" is 32°F (0°C), Category A. 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.
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SMAW (Non-Low-Hydrogen)
Non-low-hydrogen SMAW (E6010/E6011) uses cellulosic electrodes with higher hydrogen potential, assigned to Category A in Table 5.11.
For common structural shapes and plate, non-low-hydrogen SMAW with E6010 or E6011 excels at root passes on open-root groove welds where burn-through control matters. Vertical-up technique with a slight weave keeps the puddle manageable. Rod consumption runs about 10-12 electrodes per pound of weld metal deposited. Electrode stubs should be no shorter than 2 inches to maintain adequate arc length control.
SMAW Tips for Common Structural Steels
For A36 structural steel (36 ksi yield), E6010 at 80–130 A (1/8" rod) is the preferred root-pass electrode for open-root groove welds, field tack welds, and erection connections where rod oven access is impractical. E6011 runs on AC or DC — an important advantage for generator-powered field welders with AC output. Category A applies: 32°F minimum up to 3/4", 50°F up to 1-1/2".
Typical values for reference — always verify against your approved WPS and electrode manufacturer data.
Why SMAW (non-low-hydrogen) for A36 at up to 3/4"
Why SMAW (non-low-hydrogen) for A36 at up to 3/4"? SMAW (non-low-hydrogen) delivers 3-5 lb/hr deposition — compared to <a href="/welding/preheat-calculator/a36/saw/up-to-3-4-inch/">SAW</a> at 15-40 lb/hr. Position capability: all positions. Suitability: field and shop.
A36
ASTM A36 is the most commonly specified structural steel in North America, with a minimum yield strength of 36 ksi and 58-80 ksi tensile range. It appears in both Category A (non-low-hydrogen SMAW) and Category B (low-hydrogen processes) of Table 5.11. A36 is available as plate (up to 8" thick), W-shapes, channels, angles, and bars from virtually every domestic mill. Its moderate carbon content (0.26% max for shapes, 0.25% max for plate up to 3/4") and typical carbon equivalent of 0.35-0.42 give it good weldability across all prequalified processes. A36 plate thicker than 1-1/2" carries a slightly higher carbon limit of 0.29%, while plate from 3/4" to 1-1/2" stays at 0.25% max.
Why This Preheat for A36 with SMAW
Widely used structural carbon steel with 36 ksi yield and 0.26% max carbon. At this thickness, SMAW with non-low-hydrogen electrodes places the joint in Category A of Table 5.11. The minimum preheat of 32°F compensates for the higher diffusible hydrogen from cellulosic electrode coatings. The thicker the material, the longer hydrogen takes to escape the heat-affected zone, which is why preheat rises with thickness even for this common grade.
Typical Applications for A36
Common in angle-to-gusset fillet welds, beam web clip angles, stiffener plates, base plate bearing connections, light bracing members, stair stringers, handrail posts, and miscellaneous steel fabrication. A36 plate is the default choice for connection elements such as shear tabs, moment end plates under 36 ksi demand, and simple beam-to-column seated connections. In retrofit and renovation, A36 angles and channels are standard for reinforcement brackets and framing infill. Typical shop drawing callouts include 3/8" and 1/2" A36 plate for gussets, 5/16" fillet welds on clip angles, and partial joint penetration groove welds on base plate stiffeners. A36 is so ubiquitous that most structural steel shops maintain permanent inventory in multiple thicknesses from 1/4" through 2" plate. Fillet weld sizes on A36 connections typically range from 3/16" minimum to 5/8" for heavy gusset-to-column welds, with E70XX electrodes providing significant overmatching strength.
Why Preheat Matters at up to 3/4"
Thin material sheds heat quickly, allowing hydrogen to escape the HAZ readily — lowest preheat tier in Table 5.11.
Why 32°F for A36?
A minimum preheat of 32°F (0°C) means no active preheating is needed above freezing conditions. Table 5.11 Category A at this thickness assigns the ambient minimum because A36 with non-low-hydrogen SMAW has sufficient ductility and low enough carbon equivalent that hydrogen cracking risk is minimal at this section thickness. Per footnote (a), if working below 32°F, preheat the joint to at least 70°F (20°C) and maintain during welding.
Other Steels with SMAW (non-low-hydrogen) at up to 3/4"
A36 with SMAW (non-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.
A36 Welding Guides
Primary sources
D1.1:2025 reference data. Not affiliated with AWS.
Application context
A36 plate at or below 3/4 inch with SMAW using non-low-hydrogen electrodes — most commonly cellulosic E6010 or E6011 — is the field-rework and root-pass combination where positive penetration and operator-side arc control matter more than the hydrogen-control benefits of low-hydrogen electrodes. This is Category A in Table 5.11, distinct from the Category B path used by SMAW-LH/SAW/GMAW/FCAW on the same steel.
Pre-weld notes
Cellulosic and rutile electrodes deposit weld metal with substantially higher diffusible hydrogen than the low-hydrogen E70xx series, which is why Table 5.11 places non-low-hydrogen SMAW in Category A with its own preheat row. At thin section the 32°F floor matches Category B numerically, but the categories diverge at the higher thickness bands — Category A pushes to 150°F at the 3/4 to 1-1/2 inch band where Category B holds at 50°F, and the gap widens at heavier sections. The Clause 7.3.2.1 holding-oven discipline does not apply to non-LH electrodes the same way; their shipping container handling, dryness check, and operator-side arc control dominate.
What a CWI verifies
A CWI on A36 non-low-hydrogen SMAW thin-section work verifies (1) electrode classification on the can against the WPS-cited type — cellulosic, rutile, and other non-low-hydrogen variants are not interchangeable, (2) the WPS scope explicitly covers non-low-hydrogen SMAW (Category A), since most modern WPSs default to low-hydrogen and Category B, (3) the joint detail and matching-strength filler from Table 5.7 Group I, and (4) operator-side variables — arc length, travel angle, oscillation pattern — because non-LH electrode arc control is more operator-sensitive than LH.