What are differences between API 5L PSL1 and PSL2 steel pipe ?

What are differences between API 5L PSL1 and PSL2 steel pipe ?

API 5L generally refers to the implementation standard of steel line pipe, which is used to transport oil, gas and water extracted from the ground to oil and natural gas industry enterprises.

steel line pipe includes seamless steel tube and welded steel tube. Currently, welded steel tube types commonly used on pipelines in China include spiral submerged arc welding tube (SSAW), straight seam submerged arc welding tube (LSAW) and resistance welding tube (ERW). Seamless steel tube is generally used when the diameter of pipeline is less than 152mm.

Raw material of API 5L steel tube has many kinds of steel grades, such as GR.B, X42, X46, X52, X56, X60, X70, X80, etc. Now large steel mills have developed pipeline steel tube with steel grades of X100 and X120. The higher the requirements for raw materials and production, the higher the steel grade is, and the carbon equivalent between different steel grades is strictly controlled.

When it comes to API 5L, we all know that there are two standards below it, PSL1 and PSL2. Although the difference is only one word, the contents of these two standards are quite different. This is like GB/T9711.1.2.3 standard almost, all say the same, the requirement is a thousand miles apart.

Let me elaborate on the differences between PSL1 and PSL2:

PSL is short for product specification level. The product specification level of pipeline pipe can be divided into PSL1 and PSL2, which can also be said that the quality level can be divided into PSL1 and PSL2.

PSL2 is higher than PSL1, and these two specifications have different requirements not only for inspection, but also for chemical composition, mechanical properties and tolerance. Therefore, when placing an order according to API 5L, in addition to the usual indicators such as specification and steel grade, the contract must also indicate the product specification level, namely, PSL1 or PSL2.

PSL2 is superior to PSL1 in chemical composition, tensile property, impact work, nondestructive testing and other indexes.

1. Chemical composition

API 5L PSL1 chemical compositionAPI 5L PSL2 chemical composition

2. Mechanical Properties

PSL1 does not require impact performance. For all steel grades of PSL2 except X80, the average value of Akv at 0℃ at full size: longitudinal ≥41J, transverse ≥27J, at the same condition for X80: longitudinal ≥101J, transverse ≥68J


PSL2 mechanical properties

3. Tolerance

Tolerance of PSL2 pipe size
tolerance of PSL1 wal thickness tolerance of PSL2 wall thickness

4. Inspection and Defect Repair

Non-destructive inspection of a seamless pipe is mandatory for PSL2 pipe whereas for PLS1 pipe it is supplementary requirements. Repair of pipe body plate and skim by welding is not allowed in PSL2 pipes whereas it is allowed in PSL1 pipes. Similarly, weld repair without filler metal is not allowed in PSL2 pipes whereas it is allowed with purchaser’s permission in PSL1 pipes.

Baotou Steel is the top 3 manufacturer and supplier of seamless steel line pipe in China. It has the world’s most advanced production equipment PQF mill. It can fabricate GR.B, X42, X46, X52, X56, X60, X70, X80 with 1.8 million tons annual output of seamless steel pipe. If you want to learn more, please feel free to contact me.

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