A36 Preheat for SMAW (non-low-hydrogen) — 3/4" to 1-1/2"

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.

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 150°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 3/4" to 1-1/2"

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

Other Steels with SMAW (non-low-hydrogen) at 3/4" to 1-1/2"

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