Spiral Welded Pipe Classification

Spiral Welded Pipe can be applied in different area. Generally, it is widely applied for fluid service, ordinary structure, line pipe and casing. In the steel industry, we classified different steel pipe standards for different application. For detailed classification, please see the table below:
ClassificationStandardMain Products
1. Spirl Welded Pipe for Fluid Service GB/T 14291 Welded pipe for mine fluid sevice
 GB/T 3091 Welded pipe for low pressure fluid service
 SY/T 5037 Spirally submerged arc welded steel pipe for pipelines for low pressure fluid service
 ASTM A53 Black and hot-hipped galvanized welded and seamless steel pipe
 BS EN10217-2 Welded steel tybes for pressure purposes - delivery technical conditions - part2: Electric welded non- alloy and alloy  steel tubes with specified elevated temperature properties
 BS EN10217-5 Welded steel tybes for pressure purposes - delivery technical conditions - part5: submerged arc welded non-alloy  and alloy steel tubes with specified elevated temperature properties
2. Spiral Welded Pipe for Ordinary Structure GB/T 13793 Longitudinally electric resistance welded steel pipe
 SY/T 5040 Spirally submerged arc welded steel pipe piles
 ASTM A252 Welded and seamless steel pipe piles
 BS EN10219-1  Cold formed welded structural hollow sections of non-alloy and fine grain steels - part1: Technical delivert  conditions
 BS EN10219-2 Cold formed welded structural hollow sections of non-alloy and fine grain steels - part2: tolerances dimmsions and  sectional properties
3. Spiral Welded Pipe for Line Pipe GB/T 9711.1 Steel pipe for pipeline transportation system of petroleum and natural gas industries(Class A steel pipe)
 GB/T 9711.2 Steel pipe for pipeline transportation system of petroleum and natural gas industries(Class B steel pipe)
 API 5L PSL1/2 Line pipe
4. Spiral Welded Pipe for Casing API 5CT/ ISO  11960 PSL1 Steel pipe for use as casing or tubing for wells of petroleum and natural gas industries

Spiral Welded Pipe: Chemical Analysis and Mechanical Properties

Chemical Analysis and Mechanical Properties for Spiral Welded Pipe. Different steel pipe standards and steel grades have different requirements on chemical composition and mechanical properties. For detailed technical data, please check the table below:

 Standard Grade  Chemical Composition(max)% Mechanical Properties(min)
 C   Si   Mn     P       STensile Strength(Mpa)Yield Strength(Mpa)
 API 5CT  h40  -  -  -  -  0.030        417   417
 J55 - - - - 0.030 517 517
 K55 - - - - 0.030 655 655
 API 5L PSL1  A 0.22 - 0.90 0.030 0.030 335 335
 B 0.26 - 1.20 0.030 0.030 415 415
 X42 0.26 - 1.30 0.030 0.030 415 415
 X46 0.26 - 1.40 0.030 0.030 435 435
 X52 0.26 - 1.40 0.030 0.030 460 460
 X56 0.26 - 1.40 0.030 0.030 490 490
 X60 0.26 - 1.40 0.030 0.030 520 520
 X65 0.26 - 1.45 0.030 0.030 535 535
 X70 0.26 - 1.65 0.030 0.030 570 570
 API 5L PSL2  B 0.22 0.45 1.20 0.025 0.015 415 415
 X42 0.22 0.45 1.30 0.025 0.015 415 415
 X46 0.22 0.45 1.40 0.025 0.015 435 435
 X52 0.22 0.45 1.40 0.025 0.015 460 460
 X56 0.22 0.45 1.40 0.025 0.015 490 490
 X60 0.12 0.45 1.60 0.025 0.015 520 520
 X65 0.12 0.45 1.60 0.025 0.015 535 535
 X70 0.12 0.45 1.70 0.025 0.015 570 570
 X80 0.12 0.45 1.85 0.025 0.015 625 625
 GB/T 9711.1  L210 - - 0.90 0.030 0.030 335 335
 L245 - - 1.15 0.030 0.030 415 415
 L290 - - 1.25 0.030 0.030 415 415
 L320 - - 1.25 0.030 0.030 435 435
 L360 - - 1.25 0.030 0.030 460 460
 L390 - - 1.35 0.030 0.030 490 490
 L415 0.26 - 1.35 0.030 0.030 520 520
 L450 0.26 - 1.40 0.030 0.030 535 535
 L485 0.23 - 1.60 0.030 0.030 570 570
 GB/T3091/ SY/T503  Q195 0.12 0.30 0.50 0.035 0.040 315 315
 Q215B 0.15 0.35 1.20 0.045 0.045 335 335
 Q235B 0.20 0.35 1.40 0.045 0.045 370 370
 Q345B 0.20 0.50 1.70 0.035 0.035 470 470
 ASTM A53  A 0.25 0.10 0.95 0.050 0.045 330 330
 B 0.30 0.10 1.20 0.050 0.045 415 415
 ASTM A252  1  - - - 0.050 - 345 345
 2 - - - 0.050 - 414 414
 3 - - - 0.050 - 455 455
 EN10217-1  P195TR1 0.13 0.35 0.70 0.025 0.020 320 320
 P195TR2 0.13 0.35 0.70 0.025 0.020 320 320
 P235TR1 0.16 0.35 1.20 0.025 0.020 360 360
 P235TR2 0.16 0.35 1.20 0.025 0.020 360 360
 P265TR1 0.20 0.40 1.40 0.025 0.020 410 410
 P265TR2 0.20 0.40 1.40 0.025 0.020 410 410
 EN10217-2  P195GH 0.13 0.35 0.70 0.025 0.020 320 320
 P235GH 0.16 0.35 1.20 0.025 0.020 360 360
 P265GH  0.20 0.40 1.40 0.025 0.020 410 410
 EN10217-5  P235GH 0.16 0.35 1.20 0.025 0.020 360 360
 P265GH 0.20 0.40 1.40 0.025 0.020 410 410
 EN10219-1  S235JRH 0.17 - 1.40 0.040 0.040 360 360
 S275JOH 0.20 - 1.50 0.035 0.035 410 410
 S275J2H 0.20 - 1.50 0.030 0.030 410 410
 S355JOH 0.22 0.55 1.60 0.035 0.035 470 470
 S355J2H 0.22 0.55 1.60 0.030 0.030 470 470
 S355K2H 0.22 0.55 1.60 0.030 0.030 470 470


Inner Coating of Gas Pipeline

Inner coating can greatly improve pipeline capacity. It can prevent corrosion and reduce the role of the pumping costs. Improving gas flow within the coating technology development update has become the main methods of transport in major companies to increase the amount. It can significantly reduce the friction between the gas and the tube wall which is the basic function of the inner coating technology. The friction caused by the tube at the factory of its inner surface is rough, the use of the inner pipe wall coating becomes smooth, the friction between the gas and the wall becomes small. It will accelerate the gas flow rate, and the cost of pumping the respective compression lower.

The coating into a file (dry film thickness of 80 ~130 um) coated on the inner wall of the tube. Epoxy resins are currently the most widely used in the coating material, a lot of in-service pipeline are in use.

The inner coating should have a certain adhesion, porosity, elasticity, chemical resistance and corrosion resistance, and the ability hardness and resistance to pressure variations should reach a certain level. Quality epoxy resin coating on international standards to meet or exceed the requirements of API and ISO.

A typical inner coating comprises two components: a resin, which served as the basis for the role, two for epoxy curing agent, from the " curing" and "activation" role. The two components were tested liquid, respectively filling, use, or both will be mixed before use. After mixing, typically using a two-component spray equipment to be coated pipe. Regular manufacturers in the coating will be mixed according to a certain percentage ratio. The coating does not require preheating, but be careful to choose the right nozzle, the nozzle diameter and spraying pressure should comply with regulatory requirements. Nozzles are mounted at the end of the lance tube is rotated, the lance activities from one end to the other end of tube is coated work. Spraying process is regulated, the regulation has been available for a wet film thickness of 200 ~ 220um. Adjusted by the following four ways:
1. adjusting the boom travel speed
2. to adjust the rotation of the tube
3. adjusting the distance between the nozzle and the tube surface
4. adjust the spray pressure.

Steel Pipe Cleaning and Maintenance

Steel Pipe cleaning and maintenance need to follow certain methods to clean up. The main use of tools such as wire brush the surface of polished steel. Steel pipe cleaning and removal of loose or tilt can preheat the oxidation, rust, welding slag. Hand tools rust can reach Sa2 grade power tools rust up Sa3 level. If attached to a solid steel surface oxide scale, the result is not ideal tools rust, corrosion construction requirements not reach the depth of the anchor pattern.

Acid using solvent, emulsion cleaning fluid low pressure welded steel pipe surface, in order to achieve the removal of oil, grease, dust, lubricants and similar organisms, but it can not remove the steel surface rust, oxide, welding medicines, and therefore the production of anti-corrosion only as an adjunct. Different forms of ways and means to clear rust will cause some of the important impact of seamless, affecting a large number of performance and factors, in strict accordance with traditional Chinese medicine in cleaning certain principles and methods to clean up, to ensure that in use reflect a good value.

Generally two methods is used including chemical and electrolytic pickling process, pipeline corrosion using only chemical etching, to remove oxidation, rust, old coatings, sometimes used as a sand-blasting after reprocessing. Although chemical cleaning can achieve a certain surface cleanliness and roughness, but the anchor light pattern, and easy stacking of environmental pollution caused by spiral steel pipe. Rational used of means to clean up the rusty pipe fittings to ensure long time service in the production, create more production efficiency.


Knowledge of ERW Line Pipe

With the rapid development of economy and the continuous improvement of the energy demand, the pipeline as the oil and gas resources has developed in recent years. A number of medium-caliber ERW line pipe unit was completed and put into operation. ERW line pipe has been widely used in the oil and gas field gathering pipelines, oil and gas Spur. This article will focus on the circumferential residual stress on the impact of ERW line pipe manufacturing process and final product quality and control aspects of the problem.

ERW pipe forming process can be divided into two phases: the first stage of
deformation; the second stage for reducing distortion. In both phases, the steel pipe inner layer is always affected by the circumferential compressive stress and compressive deformation. The outer layer of fine molding of the bending process by weeks to the tensile stress and extension deformation: in the fine shaping and sizing process. Steel outer layer of compressive stress and compressive deformation. And ERW pipes of different specifications, the outer layer of the final strain differences. This shows that the ERW pipe inner and outer layers in the pipe circumferential strain is inconsistent. Stress state and stress the size of change.

Common problems in manufacturing process of ERW line pipe:
(1) ERW line pipe manufacturing process will bend uneven deformation of the pipe week up there is a large residual stress, so take the necessary measures to reduce the negative impact of residual stress on the ERW line pipe manufacturing process.
(2) the study and control of ERW line pipe residual stress should not be confined to the detection and analysis of the residual stress of the final product, required to pipe forming process of ERW pipeline analysis, taken from the perspective of process control measures to reduce ERW pipeline the residual stress of the pipe, reduce the adverse effects of residual stress may cause the quality of ERW line pipe.
(3) Sizing is mainly to ensure the pipe diameter to meet the requirements, the hydrostatic test is to ensure that the density of steel pipe, but for the ERW pipeline in terms of pipe, Is also an important process to reduce the circumferential residual stress.

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. Prior to 2000, the worldwide use X70, about 40%, X65, X60 are in the 30%, a considerable number of small-caliber product oil pipeline selection of X52 steel grade, mostly for resistance welding straight pipe (ERW steel pipe).

China is currently used in the Petroleum Pipeline tube spiral welded pipe (SSAW), LSAW pipe (LSAW), electric resistance welded pipe (ERW). 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, "West-East pipeline region selection 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 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 springback 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.

API 5L welded steel pipeis 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.