What kind of pipe is Line Pipe ?

What Kind of Pipe is Line Pipe ?

What is Line Pipe ?


Line pipe: it is pipe that takes oil, gas or water extracted out of the ground and send it to the petroleum and natural gas industry through pipelines.

Line pipe is a kind of pipe, just like PPC pipes, PPR pipes, they are all commonly advanced pipe material. Line pipe has a very good effect, especially in the transportation of carrying inflammable and explosive liquid and gas, whether from a security point of view, or from the Angle of efficiency, line pipe has an extraordinary quality. Therefore, line pipe is mainly used for the transportation of oil, natural gas and other fuels. So what are the detailed classifications of line pipes?


Types of Line Pipe

Common line pipe is mainly divided into two kinds of welded pipe and seamless pipe. Welded pipe is connected by fused welding line pipe, and in general its length of single pipe is longer than seamless pipe, thus it can satisfy the user’s mass quantity, but its stability is not as good as seamless tube. Seamless pipe are generally shorter, and cannot satisfy the consumer the use of the long distance, so consumers need to undertake both in the process of use.

In addition to the main classification, line pipe according to the level can be divided into three levels, they are the low temperature resistance line pipe, medium temperature resistance line pipe, high temperature resistant line pipe respectively. The level here is according to the high temperature resistance of line pipe’s ability, the higher the level is, the better the performance and safer the line pipe will be. In addition, there are many specifications of line pipe, which can meet the needs of consumers at different levels.


The Function of Line Pipe

Line pipe has the advantage of high temperature resistance and less loss, and the pipe material is generally so strong that can achieve durable. Because the line pipe has such a overwhelming advantage, so it is widely used in the transportation of oil, various gases and liquefied gases. Besides used in chemical industry and petroleum industry, line pipe is also widely used in heating conveying and water supply system in large factories.

In urban construction, pipeline pipe is also used as the transport carrier of gas and natural gas to provide clean, environmental friendly, efficient and energy-saving new energy for the city.


Common Standard and Steel Grade


PSL1 Line Pipe Mechanical properties
Grade Yield strength  Rt0,5 Mpa(psi) Tensile strength Rm Mpa(psi) Elongation 50mm or 2in
A25/A25P ≥175(25400) ≥310(45000) Af
A ≥210(30500) ≥335(48600) Af
B ≥245(35500) ≥415(60200) Af
X42 ≥290(42100) ≥415(60200) Af
X46 ≥320(46400) ≥435(63100) Af
X52 ≥360(52200) ≥460(66700) Af
X56 ≥390(56600) ≥490(71100) Af
X60 ≥415(60200) ≥520(75400) Af
X65 ≥450(65300) ≥535(77600) Af
X70 ≥485(70300) ≥570(82700) Af


PSL2 Line Pipe Mechanical properties
Grade Yield strength  Rt0,5 Mpa(psi) Tensile strength Rm Mpa(psi) Rt0,5/Rm Elongation 50mm or 2in
BR/BN/BQ 245(35500)-450(65300) 415(60200)-655(95000) ≤0.93 Af
X42R/X42N/X42Q 290(42100)-495(71800) ≥415(60200) ≤0.93 Af
X46N/X46Q 320(46400)-525(76100) 435(63100)-655(95000) ≤0.93 Af
X52N/X52Q 360(52200)-530(76900) 460(66700)-760(110200) ≤0.93 Af
X56N/X56Q 390(56600)-545(79000) 490(71100)-760(110200) ≤0.93 Af
X60N/X60Q 415(60200)-565(81900) 520(75400)-760(110200) ≤0.93 Af
X65Q 450(65300)-600(87000) 535(77600)-760(110200) ≤0.93 Af
X70Q 485(70300)-635(92100) 570(82700)-760(110200) ≤0.93 Af

IMRISTEEL is top5 manufacturer and supplier of API 5L PSL1 and pSL2 seamless steel pipe. If you have any need or further question, welcome to contact us anytime.

Anti-corrosive steel pipe with internal epoxy coating and external polyethylene (PE) coating

Anti-corrosive steel pipe with internal epoxy coating and external polyethylene (PE) coating


Anti-corrosion steel pipes with internal epoxy coating and external polyethylene coating is a new type of steel-plastic composite pipe, which has excellent mechanical properties and anti-corrosion and anti-aging properties.Widely used in water conservancy, electric power, chemical industry, petroleum and many other industries.


The anti-corrosive steel pipes with internal epoxy and external polyethylene coating is divided into: internal epoxy powder coating and external single layer PE coating steel pipe,internal  liquid epoxy coating and external single layer PE coating steel pipe, internal epoxy powder coating and external three layers PE coating steel pipe, internal liquid epoxy coating and external three -layer polyethylene coating steel pipe.


Inner epoxy coating external polyethylene coating structure composition:

  1. Steel pipesubstrate: seamless steel pipe, electric welded steel pipe(straight seam welded, spiral welded).
  2. Internal anti-corrosive coating: Sanitary grade fused epoxy powder coating, heavy anti-corrosive fused epoxy resin powder.
  3. External anti-corrosive coating: hot-melt single-layer polyethylene powder coating.

The internal epoxy coating external three-layer polyethylene (3PE) structure composition:

  1. Steel pipesubstrate: seamless steel pipe, electric welded steel pipe(straight seam welded, spiral welded).
  2. Internal anti-corrosive coating: Sanitary grade fused epoxy powder coating, heavy anti-corrosive fused epoxy resin powder.
  3. External anti-corrosion coating: hot-melt three-layer polyethylene coating, the bottom layer is fused epoxy resin powder, the middle layer is hot-melt adhesive, the outermost layer is high-density polyethylene.

Anti-corrosive steel pipe with internal epoxy coating and external polyethylene (PE) coating

Production process:

  1. Intermediate frequency heating steel pipe

Compared with the traditional electric furnace heating method, if heating has a higher conversion rate, which effectively saves the electric energy.Intermediate frequency heating is adopted, and the heat in the steel pipe is distributed from the inside to the outside, so that the heating temperature is more uniform, effectively ensuring the high quality curing of epoxy coating.

  1. Monolayer polyethylene adopts internal spray and external spray process

The technology of internal spraying epoxy powder and outer spraying polyethylene powder is called curtain method, also known as dappling process, which uses the waste heat of pipe to cure the two at the same time by means of intermediate frequency heating, and does not need to be separately coated and cured.

  1. The three-layer structure polyethylene usesthe fusion knot winding process

The internal wall is anti-corrosive coated by thermal spraying epoxy powder, and the powder is evenly coated on the internal surface of the steel pipe after high temperature heating and melting.The outer coating adopts high pressure extrusion winding technology, which greatly improves the compactness, toughness, abrasion resistance, impact resistance and bending resistance of the coating, and can effectively prevent the mechanical damage during construction and damage of plant roots and soil environmental stress in the process of use.

  1. Internal and external coatings of the steel pipes are done at the same time

Internal epoxy and external three layer PE realized synchronous coating, epoxy synchronous curing the core technology of one-time film, both inside and outside surface and spray coating not only greatly reduces the time, improve work efficiency, and coating process, the steel pipe under the internal and external coating packages at the same time, maximum reduces the heat loss, make full use of the latent heat of steel pipe, further improve the thermal efficiency.


Internal epoxy coating and external polyethylene coating pipeline characteristics:

1) The anti-fouling and anti-moth on the inner wall of the pipeline will not be attached by the fouling and anti-moth in the Marine or sewage microbial stations such as shell-shell and fungus.

2) Smooth inner coating, less fluid friction resistance than PCCP and ductile iron pipes.

3) The corrosion resistance of the inner wall of the pipe is better than that of ordinary PCCP and ductile iron pipe.

4) The single-layer polyethylene powder thermal spraying layer on the outer wall of the pipeline has strong soil corrosion resistance and environmental protection.

5) The pipe fittings with complete specifications can adapt to various installation needs.

6) The pipe can be connected by electric welding, clamp and flange.

7) Directly connected electric welding repair and repair method is simple and reliable.

8) The design life of internal and external anti-corrosive coating can reach more than 50 years.


Internal epoxy and external polyethylene anti-corrosive steel pipes are coated with corrosion resistance and deformation resistance.The outer coating is made of three-layer polyethylene with uniform coating thickness, which is closely combined with the steel pipe to improve the cathodic protection efficiency.The internal coating adopts thermosetting epoxy, the coating is hygienic and safe, and has no influence on the water quality. It can not only be used in the city supply and drainage pipe network and the long-distance transportation pipeline of tap water, sewage, medium water and sea water of various water quality, but also can be used as the transportation pipeline of oil, gas and mixed medium of oil and gas.And epoxy and polyethylene anti-corrosive steel pipe comprehensive cost is low, is in line with the green, environmental protection, low carbon, energy saving excellent products.With our more than ten years’ experience in pipe coating field,IMRI will surely provide you anti-corrosion coating steel pipes which can meet your needs.

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

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.