A633 Gr.A/C/D Preheat for SAW — over 2-1/2"

SAW (Submerged Arc Welding)

SAW submerges the arc beneath granular flux for highest deposition rates, flat/horizontal only. Category B in Table 5.11.

For pressure vessel longitudinal and circumferential seams, SAW is the primary process. Tandem or multi-wire configurations on specialized manipulators achieve consistent quality over seam lengths exceeding 40 feet. Flux basicity index per ASME Section II Part C determines the mechanical properties of the weld deposit.

Why SAW for A633 Gr.A/C/D at over 2-1/2"

Why SAW for A633 Gr.A/C/D at over 2-1/2"? SAW delivers 15-40 lb/hr deposition — the highest deposition rate among available processes. Position capability: flat and horizontal only. Suitability: shop only.

Filler Metal for SAW

Wire: EM12K or EL12 with matching flux (AWS A5.17). Common combo: F7A2-EM12K. Diameter: 3/32" or 7/64". AWS A5.17 Figure 1U uses A for as-welded and P for PWHT, not flux activity. Annex A6.1 defines active versus neutral flux by weld-metal Mn and Si change with arc voltage (Wall Neutrality Number); primary use of neutral fluxes is multipass welding and of active fluxes is single-pass welds. Voltage: 28-34V. Current: 400-800A depending on joint size. Travel: 12-24 ipm.

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

A633 Gr.A/C/D

ASTM A633 Grades A, C, and D are normalized high-strength low-alloy structural plates with enhanced notch toughness for structural applications at temperatures down to -75°F. Grade A (42 ksi yield) provides basic low-temperature service; Grade C (50 ksi yield) is the most widely specified for cold-region bridges; Grade D (50 ksi yield) offers the lowest test temperature at -75°F for Arctic service. All are normalized to produce a fine-grained microstructure that resists brittle fracture. They fall under Category B in Table 5.11, with chemistry limits (0.20% max carbon for Gr.C/D, Nb and V microalloying) producing a CE-IIW of 0.38-0.44. Charpy V-notch specimens are tested in the transverse direction at -50°F (Gr.C) or -75°F (Gr.D) with 20 ft-lbs minimum absorbed energy per ASTM requirements.

Why This Preheat for A633 Gr.A/C/D with SAW

Normalized HSLA plate with enhanced toughness for cold environments to -75°F. This steel is prequalified only with low-hydrogen processes under Table 5.11. With SAW, the submerged arc process with granular flux produces controlled hydrogen levels, with flux condition being the primary variable. The 225°F minimum preheat balances the steel’s strength level and carbon equivalent against the hydrogen control provided by SAW. Non-low-hydrogen SMAW is not an option for this grade under D1.1 prequalified WPS.

Typical Applications for A633 Gr.A/C/D

Specified for bridge pier caps in cold regions, offshore platform deck plates, Arctic pipeline support structures, cold-climate building trusses, icebreaker hull stiffeners, and polar research station framing. A633 Grades C and D provide guaranteed Charpy toughness at -40°F and -75°F respectively, making them essential for structures operating in extreme cold where brittle fracture is the primary failure mode. Impact specimen orientation (longitudinal vs transverse) affects the guaranteed toughness values and must be specified at procurement. Field welding on A633 in sub-zero ambient conditions requires heated enclosures or windbreaks to maintain interpass temperature above the Table 5.11 minimum. Filler metals for cold-region service must also meet CVN requirements at the design service temperature, typically requiring -20°F or colder impact testing. Weld procedure qualification includes impact testing of the weld metal and HAZ at the minimum design temperature.

Why Preheat Matters at over 2-1/2"

The heaviest sections demand the highest preheat in Table 5.11. Multi-pass sequences require maintaining interpass temperature throughout.

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

A633 Gr.A/C/D with SAW

Try Different Combinations

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

A633 Gr.A/C/D Welding Guides