The delivery conditions for API 5L line pipe refer to the heat treatment, machining, and final delivery condition of the steel pipe as specified by the API 5L standard upon completion of manufacturing.
API 5L line pipe is primarily used for the long-distance transportation of oil, natural gas, water, and other fluids. Its delivery conditions are determined based on the steel grade, product specification level (PSL1 / PSL2), manufacturing process, and customer technical requirements.
1. Common Delivery Conditions for API 5L Line Pipe
| Code | Delivery Condition | Main Characteristics |
|---|---|---|
| R | As-Rolled | Retains the condition after rolling; typically no additional normalizing or quenching and tempering is performed |
| N | Normalized / Normalizing Rolled | Helps improve microstructural uniformity and overall mechanical properties |
| Q | Quenched and Tempered | Increases strength and provides good toughness |
| M | Thermomechanical Rolled / Formed | Achieves the desired strength and toughness through controlled rolling and cooling processes |
Note:
According to Section 6.2 of the API 5L standard, the delivery condition for PSL1 is, in principle, selected by the manufacturer unless otherwise specified in the purchase order; PSL2 shall be supplied in accordance with the steel grade and delivery condition specified in the purchase order.
R, N, Q, and M are delivery condition suffixes in PSL2 steel grade designations; orders for PSL2 pipe must include a delivery condition suffix describing the manufacturing process. For example:
- API 5L Grade B R: Hot-rolled condition.
- API 5L Grade B N: Normalized or normalized-rolled condition.
- API 5L Grade B Q: Quenched and tempered condition.
- API 5L Grade B M: Thermomechanically rolled or formed condition.
2. Differences Between PSL1 and PSL2 Delivery Conditions
| Comparison Items | API 5L PSL1 | API 5L PSL2 |
|---|---|---|
| Delivery Condition | Determined based on conditions permitted by the standard and the manufacturer’s selection | Determined based on order requirements |
| Grade Suffix | Typically without a delivery condition suffix | Uses suffixes such as R, N, Q, M, etc. |
| Selection of Delivery Condition | At the manufacturer’s discretion, unless otherwise specified in the order | Must explicitly comply with the steel grade and condition specified in the order |
| Quality Requirements | Basic quality requirements | More stringent requirements for chemical composition, mechanical properties, and testing |
3. API 5L - Pipe Grade and Steel Grades, and Acceptable Delivery Conditions
| PSL | Delivery Condition | Pipe Grade/Steel Grade a,b |
|---|---|---|
| PSL 1 | As-rolled, normalizing rolled, normalized, or normalizing formed | L175 or A25 |
| L175P or A25P | ||
| L210 or A | ||
| As-rolled, normalizing rolled, thermomechanical rolled, thermomechanical formed, normalizing formed, normalized, normalized and tempered; or, if agreed, quenched and tempered for SMLS pipe only | L245 or B | |
| As-rolled, normalizing rolled, thermomechanical rolled, thermomechanical formed, normalizing formed, normalized, normalized and tempered or quenched and tempered | L290 or X42 | |
| L320 or X46 | ||
| L360 or X52 | ||
| L390 or X56 | ||
| L415 or X60 | ||
| L450 or X65 | ||
| L485 or X70 | ||
| PSL 2 | As-rolled | L245R or BR |
| L290R or X42R | ||
| Normalizing rolled, normalizing formed, normalized, or normalized and tempered | L245N or BN | |
| L290N or X42N | ||
| L320N or X46N | ||
| L360N or X52N | ||
| L390N or X56N | ||
| L415N or X60N | ||
| Quenched and tempered | L245Q or BQ | |
| L290Q or X42Q | ||
| L320Q or X46Q | ||
| L360Q or X52Q | ||
| L390Q or X56Q | ||
| L415Q or X60Q | ||
| L450Q or X65Q | ||
| L485Q or X70Q | ||
| L555Q or X80Q | ||
| L625Q or X90Q c | ||
| L690Q or X100Q c | ||
| Thermomechanical rolled or thermomechanical formed | L245M or BM | |
| L290M or X42M | ||
| L320M or X46M | ||
| L360M or X52M | ||
| L390M or X56M | ||
| L415M or X60M | ||
| L450M or X65M | ||
| L485M or X70M | ||
| L555M or X80M | ||
| Thermomechanical rolled | L625M or X90M | |
| L690M or X100M | ||
| L830M or X120M |
a For intermediate grades, the steel grade shall be in one of the following formats:
(1) the letter L followed by the specified minimum yield strength in MPa and, for PSL 2 pipe, the letter describing the delivery condition (R, N, Q, or M) consistent with the above formats;
(2) the letter X followed by a two- or three-digit number equal to the specified minimum yield strength in 1000 psi rounded down to the nearest integer and, for PSL 2 pipe, the letter describing the delivery condition (R, N, Q, or M) consistent with the above formats.
b The suffix (R, N, Q, or M) for PSL 2 grades belongs to the steel grade.
c Seamless only.
4. How to Select the Delivery Condition for API 5L Line Pipe?
In actual procurement and export trade, the selection can be determined based on the following factors:
1) General oil and gas transmission pipelines: Select based on steel grades such as Grade B, X42, X52, and project technical requirements.
2) Applications requiring higher strength and toughness: Consider the Q (quenched and tempered) condition.
3) When good overall mechanical properties are required: Consider the N (normalized) condition.
4) For high-strength pipeline projects: Select the M (thermomechanically rolled) condition based on the steel grade and manufacturing process.
5) For specific engineering projects: The selection should be based on the procurement technical specifications, design pressure, operating temperature, and impact toughness requirements.