A913 Gr.50/60/65 SMAW (low-hydrogen) 예열 — 3/4" to 1-1/2"

SMAW (Low-Hydrogen)

Low-hydrogen SMAW (E7018/E7016) uses basic-coated electrodes requiring rod oven storage, assigned to Category B in Table 5.11.

For high-strength shapes and plate, E7018 provides adequate tensile match for steels up to Category C. E8018-C3 or E9018-M may be required for higher-strength steels to meet weld metal strength matching requirements. Bead sequencing on thick TMCP flanges should follow qualified WPS parameters precisely to avoid overheating the refined microstructure.

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.

SMAW-LH를 사용한 A913 Gr.50/60/65의 이 예열 이유

TMCP structural shapes for seismic frames with H8-eligible reduced preheat. This steel is prequalified only with low-hydrogen processes under Table 5.11, which is why it appears in Category B but not Category A. The 50°F minimum preheat with SMAW-LH balances the steel's strength level and carbon equivalent against the controlled hydrogen input from the consumable. Non-low-hydrogen SMAW is not an option for this grade under D1.1 prequalified WPS.

A913 Gr.50/60/65의 일반적인 용도

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".

3/4" to 1-1/2"에서 예열이 중요한 이유

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

3/4" to 1-1/2"에서 SMAW (low-hydrogen)를 사용하는 다른 강재

A913 Gr.50/60/65, SMAW (low-hydrogen)

다양한 조합 시도

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

A913 Gr.50/60/65 용접 가이드