Grade and Delivery States
API 5L Grade B, also known as L245, is a specific API 5L pipe with a minimum yield strength of 241 MPa, about 35,000 psi. It is divided into two levels, PSL1 and PSL2, and has four delivery states, R, N, Q, and M, meaning as-rolled, normalized, quenched and tempered, and thermomechanically rolled.
Composition and Mechanical Properties of PSL1
For PSL1 Grade B, the chemical composition limits carbon to 0.28 percent maximum, manganese to 1.20 percent, phosphorus and sulfur to 0.030 percent each. The minimum yield strength is 241 MPa and the minimum tensile strength is 414 MPa, with elongation per the standard table. PSL1 does not require impact testing.
Composition and Mechanical Properties of PSL2
For PSL2 Grade B, carbon is limited to 0.22 percent, manganese to 1.20 percent, phosphorus to 0.025 percent, and sulfur to 0.015 percent. Yield strength is 241 to 448 MPa and tensile strength 414 to 758 MPa, with mandatory Charpy impact testing, maximum yield-to-tensile ratio of 0.93, and carbon equivalent control.
Testing Requirements
Non-destructive testing uses full-coverage ultrasonic testing supplemented by eddy current or magnetic flux leakage, with the ultrasonic classification meeting Level L2 of the applicable edition. Tensile testing verifies elongation of 22 percent minimum and hardness limits, and Charpy V-notch impact testing is critical for low-temperature performance, with an average of three specimens of at least 20 J at minus 20 degrees C for the referenced condition.
Dimensional Tolerances
The outside diameter tolerance is plus or minus 0.75 to 1.25 percent depending on size, and the wall thickness tolerance is plus 12.5 percent and minus 10 percent. Positive tolerance control ensures pressure safety margins in the delivered pipe.
Frequently Asked Questions
Q: What is the yield strength of Grade B?
A: 241 MPa minimum, about 35,000 psi.
Q: What are the four delivery states?
A: R, N, Q, and M, covering as-rolled, normalized, Q and T, and TMCP.
Q: What is the PSL2 carbon limit?
A: 0.22 percent maximum.
Q: What NDT is applied?
A: Full-coverage UT with eddy current or MFL supplement.
Q: What is the wall tolerance?
A: Plus 12.5 percent and minus 10 percent.
Q: What is the ISO designation of Grade B?
A: L245 per ISO 3183.
For API 5L Grade B pipe quotations with specification and test requirements, contact our sales team.
