A572 Gr.50 SAW 예열 — 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.

SAW with F7A2-EM12K wire/flux delivers the highest deposition rates for flat-position fillet welds on building steel. Typical parameters: 500-700 amps, 28-32 volts, 18-30 IPM travel speed. Flux consumption runs approximately equal to wire consumption by weight. Unfused flux recovery and recycling systems are standard in production shops to control consumable costs.

SAW Tips for Common Structural Steels

For A572 Grade 50 structural steel (50 ksi yield, Category B only), SAW F7A2-EM12K at 550–700 A is the dominant process for crane runway girder web-to-flange fillet welds, built-up column seams, and plate girder fabrication in building construction. The deep-penetrating SAW arc on A572 Gr.50 plate achieves excellent root fusion on fillet welds without back-gouging.

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

Filler Metal for SAW

Wire: EM12K or EL12 with matching flux (AWS A5.17). Common combo: F7A2-EM12K. Diameter: 3/32" or 7/64". Flux type: active (A) for single-pass, neutral (N) for multi-pass. 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.

A572 Gr.50

ASTM A572 Grade 50 (50 ksi minimum yield, 65 ksi minimum tensile) is the dominant high-strength low-alloy structural steel in building construction. Most W-shapes rolled today are dual-certified A572/A992, with actual yield typically 50-58 ksi. It falls under Category B only in Table 5.11 — non-low-hydrogen SMAW is not prequalified for this grade. Chemistry limits include 0.23% max carbon (shapes) and columbium (niobium) or vanadium microalloying for grain refinement, producing a typical CE-IIW of 0.40-0.45. A572 Gr.50 plate is available in thicknesses up to 6" and is the default grade for connection plates, gussets, and base plates in building construction when loads exceed A36 capacity. The Gr.42, 55, 60, and 65 grades exist but Gr.50 accounts for over 90% of A572 production.

SAW를 사용한 A572 Gr.50의 이 예열 이유

Dominant 50 ksi HSLA structural steel often dual-certified with A992. 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.

A572 Gr.50의 일반적인 용도

Dominates building construction for W-shape column splices, beam-to-column moment connections, braced frame gusset plates, base plates over 36 ksi demand, crane runway girder webs, and mezzanine floor beams. A572 Gr.50 plate is the standard for connection elements in seismic designs per AISC 341. Complete joint penetration groove welds at beam flanges are the most critical weld detail in moment frames. The most common connection plate thicknesses are 3/4" and 1" for moment end plates and 1/2" to 5/8" for shear tabs. Demand-critical welds in seismic applications require notch-tough filler metals meeting AISC 341 Section A3.4b supplemental requirements with CVN testing at -20°F. Column splice CJP welds at every 2-3 story intervals are typically 2G or 3G field welds requiring portable preheat equipment. Base plate welds to foundation embed plates carry the full column load and require strict preheat compliance on thicker plates.

over 2-1/2"에서 예열이 중요한 이유

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

over 2-1/2"에서 SAW를 사용하는 다른 강재

A572 Gr.50, SAW

다양한 조합 시도

인터랙티브 예열 계산기를 사용하여 D1.1:2025 표 5.11의 모든 강재, 공정, 두께 조합을 조회하세요.

A572 Gr.50 용접 가이드