On October 7, 2024, my old customer from Malaysia asked me on WhatsApp if he could buy 1 steel pipe from me. Our company is very willing to provide services to old customers.
A week later, the customer sent us a purchase order. This was our second cooperation. In 2023, we cooperated on a batch of steel pipes, butt-welded pipe fittings and other products. The customer was very satisfied with our quality and service.
Before production, the customer emphasized that the weld type of this welded pipe must be SAW, and we promised to meet the customer’s requirements.
Half a month later, the goods are completed and we provide customers with inspection photos.
API 5L Grade B Pipe Specification
API 5L Grade B is a carbon steel pipe standard issued by the American Petroleum Institute (API), primarily used for oil, gas, and water transmission. It is a widely used material in the pipeline industry due to its good mechanical properties and moderate strength.
The “Grade B” designation indicates the minimum yield strength of the steel,Stainless Steel , with a focus on suitability for use in pipelines. Grade B pipes are commonly used in moderate to high-pressure applications.
| Processing Method | Seamless and Welded |
| Size Range | 1/8″- 48″ / DN6 – 1200 |
| Thickness Schedule | SCH 10, SCH 20, SCH 40, STD, XS, SCH 100, SCH 120, SCH 160, XXS |
| Length | 6m or 12 m or Random |
| Standard | ASME B36.10M |
| Surface Treatment | Blasting and Painting , Epoxy Powder FBE, 2PE, 3PE Coating |
| Material Grade | ASTM A106B / A53, API 5L B / X42 / 46 / 52 / 56 / 60 / 65 / 70, A333 GR 6 |
Manufacturing:
Can be manufactured as seamless or welded pipe (ERW, LSAW, SSAW/HSAW).
Product Specification Levels (PSL):
API 5L includes two product specification levels: PSL1 and PSL2.
PSL1 is a basic quality level.
PSL2 has stricter chemical and mechanical requirements, and additional testing requirements.
Seamless and Welded Types
Seamless Type: Inlcuding hot rolled seamless for pipe diameter above 3 inch, cold rolled seamless below 3 inch.
ERW Welded Type: Electric Resistance Welded, for pipe diameter below 24 inch.
LSAW Type: Longitudinal Sub-merged Arc Welding, for pipe OD 20 inch to 48 inch. LSAW also called JCOE, it means pipe manufacturing shapes from J shape, C shape, O shape, and then cold expanding.
DSAW: DSAW involves two submerged arcs, one on each side of the steel plate, creating a double-sided weld. It is suitable for pipes with larger diameters and thicker walls.
HSAW: HSAW involves welding along a helix path, forming pipes with a spiral seam. This method is suitable for pipes with diameters ranging from medium to large.
API 5L Gr.B PSL1 Chemical Composition
| CHEMICAL | LIMITS | C | Mn | P | S | Cu | Ni | Cr | Mo |
| API 5L Gr.B PSL1 | MIN | ||||||||
| MAX | 0.28 | 1.20 | 0.03 | 0.03 | 0.5 | 0.5 | 0.5 | 0.15 |
API 5L Gr.B PSL1 Mechanical Property
| MATERIAL | T.S (MPA) | Y.S (MPA) | EL % |
| ASTM API 5LB | 415 min | 240 min | 23min |
API 5L Grade B Seamless Pipe Dimension
API 5L Grade B seamless pipe is a general purpose carbon steel pipe used in different industries. Its diameter ranges from 1/8” to 48”, and wall thickness ranges are SCH 10, SCH 20, SCH 40, STD, XS, SCH 100, SCH 120, SCH 160, XXS.
| DN | NPS | OD | SCH20 | SCH30 | STD | SCH40 | SCH60 | XS | 80 |
| 6 | 1/8 | 10.3 | – | 1.45 | 1.73 | 1.73 | – | 2.41 | 2.41 |
| 8 | 1/4 | 13.7 | – | 1.85 | 2.24 | 2.24 | – | 3.02 | 3.02 |
| 10 | 3/8 | 17.1 | – | 1.85 | 2.31 | 2.31 | – | 3.20 | 3.20 |
| 15 | 1/2 | 21.3 | – | 2.41 | 2.77 | 2.77 | – | 3.73 | 3.73 |
| 20 | 3/4 | 26.7 | – | 2.41 | 2.87 | 2.87 | – | 3.91 | 3.91 |
| 25 | 1 | 33.4 | – | 2.90 | 3.38 | 3.38 | – | 4.55 | 4.55 |
| 32 | 11/4 | 42.2 | – | 2.97 | 3.56 | 3.56 | – | 4.85 | 4.85 |
| 40 | 11/2 | 48.3 | – | 3.18 | 3.68 | 3.68 | – | 5.08 | 5.08 |
| 50 | 2 | 60.3 | – | 3.18 | 3.91 | 3.91 | – | 5.54 | 5.54 |
| 65 | 21/2 | 73.0 | – | 4.78 | 5.16 | 5.16 | – | 7.01 | 7.01 |
| 80 | 3 | 88.9 | – | 4.78 | 5.49 | 5.49 | – | 7.62 | 7.62 |
| 90 | 31/2 | 101.6 | – | 4.78 | 5.74 | 5.74 | – | 8.08 | 8.08 |
| 100 | 4 | 114.3 | – | 4.78 | 6.02 | 6.02 | – | 8.56 | 8.56 |
API 5L Grade B ERW Pipe Tolerance
| OD Tolerance | WT Tolerance | ||||
| A, B | X42 ~ X70 | ||||
| D<60.3milimeter | +0.41/-0.40milimeter | D<73milimeter | +20%/-12.5% | D<73milimeter | +15%/-12.5% |
| D>=60.3milimeter | +0.75/-0.40milimeter | D>=73milimeter | +15%/-12.5% | D>=73milimeter | +15%/-12.5% |
How to inspect API 5L Grade B Pipe
Visual & Dimensional Inspection
Surface Defects – Check for cracks, dents, pits, laminations, and other imperfections.
Pipe Ends– Ensure smooth, beveled, or threaded ends as required.
Dimensions – Verify outer diameter (OD), wall thickness (WT), and length using calipers, micrometers, and ultrasonic thickness gauges.
Chemical Composition Analysis
Spectroscopy (PMI – Positive Material Identification) – Ensures compliance with API 5L Grade B chemical limits.
Carbon, Manganese, Phosphorus, and Sulfur content must meet the specified range.
Applications
✅ Oil & Gas Pipelines
✅ Water Transmission Lines
✅ Structural Applications
✅ Petrochemical & Refinery Pipelines
✅ Offshore & Onshore Pipelines