API 5L Gr.B SMAW (non-low-hydrogen) 예열 — up to 3/4"

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.

On pipe joints, non-low-hydrogen SMAW root passes with E6010 use the keyhole technique to ensure complete penetration. Pipe rotation (roll welding) is preferred when practical; fixed-position welding requires 5G or 6G qualified procedures. The cellulosic coating generates significant spatter, so adjacent base metal should be protected with anti-spatter compound.

SMAW Tips for Pipe and Tube Steels

For API 5L Grade B pipeline (35 ksi yield), E6010 is the standard root pass electrode for structural attachments to transmission pipe governed by D1.1 — bell-hole tie-in welds, pipe shoe welds, and anchor block attachment welds. DC+ polarity at 80–110 A (1/8" rod) on fixed-position field joints. Pipeline girth welds qualifying under API 1104 follow separate procedures, but D1.1.

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

Filler Metal for SMAW

Electrode: E6010 (DC+ only) or E6011 (AC/DC) per AWS A5.1. Cellulosic coating — NOT low-hydrogen. Diameter: 1/8" (root passes, all-position), 5/32" (fill passes). No oven storage required. These electrodes intentionally produce higher hydrogen for deeper penetration — the tradeoff is higher required preheat per Table 5.11 Category A.

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

API 5L Gr.B

API 5L Grade B is the baseline pipeline steel specification used for oil, gas, and water transmission lines, with 35 ksi minimum yield and 60 ksi minimum tensile (PSL 1). At PSL 2, tighter chemistry controls (0.22% max carbon, 1.20% max manganese, 0.43% max CE-IIW) improve weldability and toughness consistency. Grade B pipeline joints welded under D1.1 follow Category A (non-low-hydrogen) and Category B (low-hydrogen) preheat requirements. API 5L covers both seamless and welded (HFW, SAW, COWB) pipe in sizes from 1/2" through 80" outside diameter. The pipeline industry typically qualifies procedures under API 1104 rather than D1.1, but structural attachments to pipeline components often fall under D1.1 jurisdiction.

SMAW를 사용한 API 5L Gr.B의 이 예열 이유

Baseline pipeline steel for oil and gas transmission at 35 ksi yield. At this thickness, SMAW with non-low-hydrogen electrodes places the joint in Category A of Table 5.11. The minimum preheat of 32°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.

API 5L Gr.B의 일반적인 용도

Specified for water transmission mains, natural gas distribution laterals, irrigation pipelines, fire hydrant supply loops, sewer force mains, and gathering system tie-ins. API 5L Gr.B pipeline girth welds use root passes with E6010 cellulosic electrodes followed by fill passes with E7018 or GMAW. Bell-hole repair joints and split-tee hot taps are typical field weld configurations. Pipeline wall thicknesses for municipal water service typically range from 0.250" to 0.500" depending on diameter and operating pressure. Mainline girth welds are radiographically inspected at 100% on high-consequence area crossings and river/road bores. Pipe diameters in municipal water range from 6" to 48" NPS, with 12" to 24" being the most common for trunk mains. Field welders typically qualify on 6G fixed pipe to demonstrate proficiency in all positions encountered during mainline tie-in and repair operations.

up to 3/4"에서 예열이 중요한 이유

Thin material sheds heat quickly, allowing hydrogen to escape the HAZ readily — lowest preheat tier in Table 5.11.

API 5L Gr.B에 32°F인 이유?

최소 예열 32°F (0°C)는 영하 이상 조건에서 능동적 예열이 필요 없음을 의미합니다. 이 두께에서 표 5.11 범주 A는 API 5L Gr.B이 비저수소 SMAW으로 충분한 연성과 낮은 탄소 당량을 가져 수소 균열 위험이 최소이므로 주위 최소값을 지정합니다. 각주 (a)에 따라 32°F 미만에서 작업 시 최소 70°F (20°C)로 예열하고 용접 중 유지하십시오.

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

API 5L Gr.B, SMAW (non-low-hydrogen)

다양한 조합 시도

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

API 5L Gr.B 용접 가이드