A913 Gr.50/60/65 Preheat for FCAW — up to 3/4"

FCAW (Flux Cored Arc Welding)

FCAW uses tubular flux-cored wire, available gas-shielded (E71T-1) or self-shielded (E71T-8) for field work. Category B in Table 5.11.

High-strength FCAW wire follows the steel's Table 5.6 base-metal group, not its Table 5.11 preheat category: Table 5.7 marks AWS A5.20 carbon-steel wire N/A for Groups III, IV and V and lists AWS A5.29 low-alloy classifications such as E8XTX-K2X for Group III and E9XTX-K2X for Group IV. The flux system in these wires is formulated for low diffusible hydrogen, often meeting H8 supplementary limits when tested per AWS A4.3. Wire storage requires climate-controlled conditions similar to SMAW electrodes to prevent moisture absorption.

FCAW Tips for High-Strength and TMCP Steels

For A913 Grades 50/60/65 TMCP shapes (CE-IIW 0.35–0.42), FCAW E71T-1M at 220–260 A with 0.045" wire is well-suited for heavy W14 column splice CJP welds and beam-to-column continuity plate fillets. With H8-certified E71T-1M, qualifies for Category D (32°F all thicknesses) — practical for year-round column splice erection without propane preheat equipment. D1.1 Clause 7.7 heat input limitations do NOT apply to A913/A913M.

Typical values for reference — always verify against your approved WPS and electrode manufacturer data.

Filler Metal for FCAW

Gas-shielded: E71T-1C (AWS A5.20, classified with 100% CO2) or E71T-1M (classified with 75 to 80 percent argon, balance CO2). The C and M designators identify the shielding gas used for classification; the actual gas must follow the electrode manufacturer and the qualified WPS. Self-shielded: E71T-8 (no external gas, field-ready). Diameter: 0.045" standard, 1/16" for high-deposition. Stick-out: 3/4" to 1-1/4" (longer than GMAW due to resistive heating of flux core).

Typical values for reference — always verify against your approved WPS and electrode manufacturer data.

A913 Gr.50/60/65

ASTM A913 Grades 50 (50 ksi yield), 60 (60 ksi yield), and 65 (65 ksi yield) are quenched-and-self-tempered (QST) structural shapes produced by thermo-mechanical controlled processing (TMCP) — an in-line water quench immediately after the final rolling pass, followed by self-tempering from the core heat. This produces a fine-grained bainitic/ferritic microstructure throughout the full cross-section with carbon content typically 0.10-0.16% and CE-IIW of 0.35-0.42. Standard low-hydrogen processes use Category B; H8-certified consumables qualify for the reduced Category D (32°F all thicknesses), reflecting the inherent hydrogen cracking resistance of the TMCP microstructure. Available exclusively as W-shapes (primarily W14 heavy column sections), A913 is not produced as plate or other forms. The QST process eliminates the need for separate mill heat treatment, providing consistent through-thickness properties.

Why This Preheat for A913 Gr.50/60/65 with FCAW

TMCP structural shapes for seismic frames with H8-eligible reduced preheat. This steel is prequalified only with low-hydrogen processes under Table 5.11. With FCAW, flux-cored wire in FCAW provides a combination of deoxidizers and low-moisture flux formulations that control hydrogen. The 32°F minimum preheat balances the steel’s strength level and carbon equivalent against the hydrogen control provided by FCAW. Non-low-hydrogen SMAW is not an option for this grade under D1.1 prequalified WPS.

Typical Applications for A913 Gr.50/60/65

Specified for seismic moment frame columns, high-rise building corner columns, transfer girder bearing seats, heavy truss chords, stadium cantilever support columns, and parking garage moment frame members. A913 TMCP shapes eliminate the need for post-rolling heat treatment, providing consistent through-thickness properties from flange tip to web center. Column splice CJP welds and beam-to-column continuity plate fillet welds are the critical weld joints. Available in W14 sections from W14x132 through W14x730, these shapes are the backbone of seismic column design in high-rise construction. The TMCP process creates a fine-grained microstructure throughout the full cross-section, unlike conventional heat-treated shapes that may have property gradients. The H8 path to Category D (32°F all thicknesses) offers significant fabrication cost savings on heavy column splices that would otherwise require 150-225°F preheat under Category B. Column flange thicknesses on W14x455 and heavier sections exceed 3".

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.

Other Steels with FCAW at up to 3/4"

A913 Gr.50/60/65 with FCAW

Try Different Combinations

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

A913 Gr.50/60/65 Welding Guides