API 5L-B is a pipeline steel conforming to the API SPEC 5L standard, corresponding to the domestic grade L245 (GB/T 9711 standard). The "L" in its name stands for Line, and "245" indicates a minimum yield strength of 245 MPa. It is mainly used in oil and gas pipelines (such as oil pipelines and natural gas pipelines), chemical engineering, and offshore platform structures due to its combination of corrosion resistance and high strength.
API 5L Grade B Temperature Range
Standard Service Temperature:
-46°C to 427°C
Reference: API SPEC 5L (46th Ed., Table 9)
Critical Limits:
Above 427°C: Significant high-temperature strength degradation (yield strength reduction ≥30%)
Below -46°C: Requires Gr.B L245N/L360N cryogenic grades (Charpy impact ≥40J at -60°C)
H₂S Environment Requirements:
In sour service: ≤120°C recommended → Prevents sulfide stress corrosion cracking (per NACE MR0175)
API 5L Grade B Carbon Steel Pipe Tensile Strength
| Yield Properties a R t0,5 PSI Min |
Elongational (in 2in Af % min) |
Tensile Properties grade a Rm PSI Minimum |
Tensile Properties grade b Rm PSI Minimum |
|
|---|---|---|---|---|
| Gr B | 36,500 | c | 60,200 | 65,200 |
Grade B SAW Pipe Chemical Compatibility Chart
| PSL1 | PSL2 | |||||||
|---|---|---|---|---|---|---|---|---|
| Gr | C | Mn | P | S | C | Mn | P | S |
| B | 0.27 | 1.30 | 0.05 | 0.03 | 0.24 | 1.20 | 0.020 | 0.010 |
Mechanical Characteristics of API 5L gr. B Erw Pipe
| Grade | Yield Strength | Tensile Strength | Elongation | ||||||
| Min | Max | Min | Max | E=1944 A 0.2 / U 0.9 | |||||
| Ksi | MPa | Ksi | MPa | Ksi | MPa | Ksi | MPa | ||
| B | 35 | 241 | 65 | 448 | 60 | 414 | 110 | 758 | |
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