What is The Meaning of API 5L Line Pipe?

General Information of API 5L Line Pipe:

Specifications for API 5L adhere to the International Organization for Standardization ISO 3183. The API 5L specification provides standards for pipe suitable for use in conveying gas, water, and oil in the natural gas and oil industries. The API SPEC 5L covers seamless and welded steel line pipe. It includes standard-weight and extra-strong threaded line pipe; and standard-weight plain-end, regular-weight plain-end, special plain-end, extra-strong plain-end, special plain-end, extra-strong plain-end pipe; as as well as bell and spigot and through-the-flow line(TFL) pipe.

Grades covered by this specification are A25 ,A ,B (and the following "X" Grades), X42, X46, X52, X56, X60, X65, X70, X80. The two digit number following the "X" indicates the Minimum Yield Strength (in 000's psi) of pipe produced to this grade.

Pipe manufactured to ASTM106 Grade A or B are not interchangeable with API 5L. Requirements to API 5L X grades are more stringent, rolled grades are not acceptable and rework is not allowed. Moreover, particular attention is given to toughness and toughness tests for sour services and higher pressure & temperature classes.

Applications and benefits of API 5L Line Pipe:

1. API 5L line pipe is preferred in long pipelines due to its inexpensiveness, so it is widely used in gas, water and oil transportation.
2. API 5L line pipe can resist to crack propagation, so it used to pipeline steel.
3. Line Pipe and Sour Service Line Pipes.

Production Equipments of Precision Welded Pipe

In the process of three typical production methods, the main pipe equipment, pipe forming unit cold drawing machine, cold rolling unit and cold reducing unit, has a decisive role in the formation of precision welded pipe. But the equipment types of precision pipe pipe is much, the range of that is big, and technical performance requirements are different. If we want to meet the quality requirements of precision welded pipe, we must be suitable configuration.

1. On the manufacturing stage of precision welded pipe:

Strip preparation - Desktop rack or chain conveyor
Uncoiler - Cantilever or Double Cone Uncoiler
Straightening of steel - Roller leveling machine
Shear - oblique cutting shears
Butt welding machine
Live sets of materials - live sets (box, cage, spiral, tunnel, etc.)
Milling edge planing edge - milling edge planing machine
Forming - continuous forming machine (roll, row roll, FF forming, etc.)
Welding - high frequency induction or contact heating welding equipment
Clear burrs - inside and outside deburring devices (both inside and outside)
Weld heat treatment - IF linear induction heating device (or steel pipe heat treatment)
Cooling - air cooling and cooling water jacket
Sizing - continuous sizing machine (roll)
Nondestructive testing - Ultrasonic or eddy current flaw detection
Flying shear - flying shear (stamping, rolling, sawing, milling, etc.)
Straightening - Roller Straightening Machine (5 ~ 7 Roll)
Cut off the flat head - cutting machine and the head machine and step into the bench
Eddy current testing - eddy current flaw detector (instead of hydraulic pressure test)
Water pressure test - hydraulic pressure test machine (single or multi-type)

2. On the cold drawn and cold rolling stage of precision welded pipe:

Rolling head - rolling head or hammer machine
Intermediate heat treatment - continuous roll annealing furnace
Pickling, cleaning - pickling, washing tanks and flushing facilities
Phosphating, saponification - phosphating, saponification tank
Cold drawing - cold drawing unit
Lubrication - Lubricating pond
Cold Rolling - Roller Cold Rolling Mill
Heat treatment of the finished product - Protection atmosphere Heat treatment furnace (chamber or roll)

3. Cold reduction stage of precision welded pipe:

Cold reduction - cold reduction unit (two or three roller type cold reduction unit frame according to the total amount of deformation configuration)

As the precision welded pipe varieties, specifications, technical requirements are different, the production process and processes are not the same, some processes take a long time, some processes less time, so the production process prone to uneven, and the need for a buffer link, In order to make the smooth progress of production, to minimize the weak links, about 90% of the precision welded pipe products have to go through the middle of the warehouse to balance production capacity.

The Characteristic of Seamless Precision Steel Tube

Precision steel pipe is a kind of steel pipe that inside and outside of the wall are without oxidation layer, withstand high pressure without leakage, high precision, high finish, cold bending is not deformed, flaring, flattening no cracks and so on. The main advantage of seamless precision steel tube is characterized by a smaller diameter, high precision, high precision, good surface quality, better performance, more dense metal. It has strict requirements on the pipe body bore, the outer wall size and the tolerance and roughness. Seamless precision steel pipe is mainly used for mechanical structure, hydraulic equipment, hydraulic and pneumatic cylinder manufacturing.

The characteristic of seamless precision steel tube:

1. Finished tube size accuracy, internal and external diameter can be accurate to within 0.05mm.
2. Internal and external surface finish is good.
3. There is no oxide film on the inner and outer surfaces of the precision tube after cold rolling.
4. Precision pipe flaring, flattening no cracks, cold bending is not deformed, can withstand high pressure.
5. Performance is superior, can make a variety of complex deformation and mechanical deep processing.

The uses of seamless precision steel pipe:

1. Precision tube for automobile manufacturing, precision pipe for automobile parts, precision tube for precision equipment, Precision pipe for boiler equipment.
2. Motor shell with precision tube, motor shell, DC motor tube.
3. Industrial processing categories: machinery manufacturing with precision pipe, machine tool processing with precision tube, bearing pipe with precision pipe, processing machinery parts, etc. High pressure tubing, hydraulic cylinder.
5. Other: electrical gas transmission, water power pipes and so on.

Low-frequency Electric Resistance Welding

Low-frequency electric resistance welding (LF - ERW), is an obsolete method that was used to weld seams in oil and gas pipelines. It was phased out in the 1970s but as of 2015 some pipelines built with this method remained in service.

Electric resistance welded pipe (ERW steel pipe) is manufactured by cold-forming a sheet of steel into a cylindrical shape. Current is then passed between the two edges of the steel to heat the steel to a point at which the edges are forced together to form a bond without the use of welding filler material. Initially this manufacturing process used low frequency A.C. current to heat the edges. Over time, the welds of low frequency ERW pipe was found to be susceptible to selective seam corrosion, hook cracks, and inadequate bonding of the seams, so low frequency ERW is no longer used to manufacture pipe. This low frequency process was used from the 1920s until 1970. In 1970, the low frequency process was superseded by a high frequency ERW process which produced a higher quality weld. So the high frequency process is still being used to manufacture pipe for use in new pipeline construction. In the production of ERW steel pipe manufactured by Prime Steel Pipe, high-frequency ERW process is widely used, so that we can guarantee the quality of welding seam and produce high quality ERW steel pipe.

Advantages and Application of LSAW Steel Pipe

Longitudinal Submerged Arc Welded Pipe or simply LSAW steel pipe and Straight Seam Submerged Arc Welded Pipe or simply SSAW steel pipe belong to submerged-arc welding (SAW). But LSAW steel pipe adopts single steel sheet as raw material, its advantages include: the thickness of the steel plate can reach more than 100mm, and there is no crescent bends; since it is straight seam, forming is more convenient, but also it is easy to weld tracking, which is suitable for two-step pre-precision welding production; and there is the whole body of mechanical expansion process, which can basically eliminate the residual stress. All of advantages above make LSAW can be produced big diameter steel pipe (the maximum can reach 1422mm), high-grade pipe (50mm), high steel grade (X80/X100/X120), and large structure tube that used in two, three, four types of regional and marine engineering. LSAW steel pipe and high-frequency Longitudinal Welded Pipe (HFW steel pipe) all belong to Longitudinal Welded Pipe, but the high-frequency welded pipe can be made of medium and small welded pipe (400mm), and there is intermediate frequency heat treatment process. When the diameter, steel grade is the same, high-frequency welded pipe is more superior, for example, foreign pulp pipe often use high-frequency welded pipe (HFW).

The Characteristics and Use of Precision Welded Pipe

Precision welded pipe is a broad concept, according to the different use requirement, there are many different personalized quality requirements. Precision welded pipe is the further improved result that based on the general welded steel pipe, is the fine products in the welded steel pipe products. Prime Steel Pipe as the comprehensive steel pipe manufacturer and exporter from China, has been committed to provides high-quality steel pipe for sale, if you have any requirement of precision welded pipe, please contact us.

Key Features of Precision Welded Pipe

Precision welded pipe has a fine geometric size, thickness of the transverse wall is uniform, shape of steel pipe is good, oval is small, the quality of welding line is good and burrs are small, the outer surface is smooth. Steel pipe after welding line heat treatment or protective atmosphere heat treatment, can achieve the effect of surface without oxygen, steady mechanical properties and metallurgical uniform. Its production costs are much lower than similar seamless steel pipe, and it can be directly or after a small amount of processing used for some equipment, which will reduce equipment processing costs.

Use of Precision Welded Pipe

Precision welded pipe is mainly used in chemical, textile, machinery, instrumentation, aviation, automotive and other fields. Such as cars, motorcycles on the buffer, reducer, condenser, tank pipe, drive shaft, silencer, control shaft, thrust brake tube, hydraulic cylinder, cylinder, jack, all kinds of conveyor rollers, belt roller, Textile printing and dyeing roller, textile fiber machine with draft pipe, hydraulic support tube, deep well pump pipe, all kinds of mechanical light pipe, electric heater outer tube and household appliances, etc..

API 5L Welded Steel Pipe

API early in 1926 released by the American Petroleum Institute (API) API-5L standard, initially including three steel grade A25, A, B, and later released several times. API 5L welded steel pipe is mainly used for the delivery of the onshore and offshore oil and gas, coal slurry, the slurry media and offshore platforms, power plants, chemical industry and urban construction, structural tubes.

China is currently used in the Petroleum Pipeline tube spiral welded pipe (SSAW steel pipe), LSAW steel pipe, electric resistance welded pipe (ERW steel pipe). Diameter less than 152mm selection of seamless steel tubes. Of the late 1960s to the 1970s, spiral pipe plant rapid development of crude oil pipelines almost all spiral welded steel pipe. The spiral welded steel pipe of the disadvantage is the internal stress is large, the dimensional accuracy is poor, the probability of generation of defects. According to expert analysis, should adopt the policy of "walking on two legs", and actively carry out technological transformation now spiral welded pipe plant, also in promising; vigorously develop straight seam submerged arc control tube industry in China. ERW steel pipe with a smooth appearance, high dimensional accuracy, lower prices, and has been widely used at home and abroad.

Straight seam high frequency welded steel molding process that used in the production of LSAW steel pipe by Prime Steel Pipe is with advanced, reliable quality, welding position, stable welding parameters, welding speed, high yield, and the entire production line equipment and technology are world-class level.

(1) straight seam high frequency welded steel pipe forming process spring back small residual stress.
(2) the strain hardening effect is small, precise geometric dimensions full circle, will help ensure the quality of construction and welding.
(3) straight seam high frequency welded steel bead shape is good, not prone to biting edge, inside and outside the weld misalignment defects.
(4) straight-seam pipe weld distributed in a point on the circumference and, therefore, according to the demand to weld on a favorable position.