• ASTM A333 Grade 6 Pipe, A333 Seamless Pipe, ASTM A333 Gr6 Pipe,ASTM a333 gr6 steel pipe,ASTM A333 Grade 6 seamless pipe
  • S355J2(Q345D) Square Steel Pipe
  • U type finned tube


Location : home > News

What is a SSAW steel pipe?

Posted on 2020/12/01
What is a SSAW steel pipe?
SSAW steel pipe is also known as the Spiral Submerged- Arc Welded Steel Pipe that is a type of spirally welded steel pipe produced by using the double-sided submerged arc welding method. Spiral welded pipes are formed using narrower plates or hot rolled coils, which lowers their production costs significantly. The spiral welding process permits the production of large-diameter pipes suitable for transporting large volumes of oil and gas. Traditional SSAW pipes were historically limited to low pressure applications; however, modern SSAW pipes have been used extensively in Russia, Canada, and Asian countries in high pressure gas pipelines.
Standard and Classfication Disadvantages
Chemical Analysis and Mechanical Properties How to Identify The Quality
Production process How to Test the Stress Resistance
How to Increase the Stability Difference between ERW, SSAW, LSAW
Advantages How to Choose the SSAW Steel Pipe
Generally used: welded pipes convey fluid, metal structures, pile and so on. Our products are widely used in water engineering, petrochemical industry, chemical industry, power industry, agricultural irrigation, urban construction, and spiral submerged steel pipe is one of 20 key products of development. For the transport of liquids: water supply, drainage. For gas transportation: gas, steam, liquefied petroleum gas. For structural purposes: as piling pipe, for bridges; piers, roads, buildings and other structures tube.
The SAWH steel pipe is the spiral submerged arc welding steel pipe for short. It is made adopting sumberged arc welding technique and comes with a welding seam.
Datang has overwhelming advantages over cometiotors in manufacturing this SAWH steel pipe.We have 10 traditional one-step production lines and 1 two-step production line that enabels to produce finely pre-welded SAWH steel pipe of 360000 tons per year,and we have become the leading enterprise in this industry in virtue of large productivity and advanced technical equipment.

SSAW steel pipe internal thread display

SSAW steel pipe internal thread display
Standard: API 5L, API 5CT, ASTM A252, ASTM 53, EN10217, EN10219, BS, JIS, IS
Out Diameter: 219.1 mm – 2540mm (8″-100″)
Wall Thickness: 3.2mm – 25.4mm
Length: 6 – 22 m
Steel Grade: API 5L: GR A, GR B, X42,X46, X56, X60,X65,X70
ASTM A252 GR 1, GR 2, GR 3
BS 4360: Grade 43, Grade 50
EN:S275, S275JR, S355JRH, S355J2H
Surface:Fusion bond Epoxy coating, Coal Tar Epoxy, 3PE, Vanish Coating, Bitumen Coating, Black Oil coating as per customer’s requirement
Test:Chemical Component Analysis, Mechanical Properties (Ultimate tensile strength, Yield strength, Elongation), Technical Properties (Flattening Test, Bending Test, Blow Test, Impact Test, Exterior Size Inspection, Hydrostatic Test, X-ray Test

SSAW steel pipe (spiral submerged arc welded steel pipe) is formed by spiral bending of hot-rolled strip steel, and spiral seam steel pipe (also called spiral welded pipe, spiral pipe spiral steel pipe) is formed by automatic welding of submerged arc for inner and outer joints. It can be widely used in the production of large diameter steel pipes for the following reasons:
1) As long as the forming angle is changed, it is possible to produce steel pipes of various calibers with strips of the same width;
2) Because the continuous bending is formed, the length of the steel pipe is not limited;
3) The weld spiral is evenly distributed on the circumference of the whole steel pipe, so the steel pipe has high dimensional accuracy and high strength;
4) It is easy to change the size and is suitable for the production of small batch and multi-type steel pipes.
Since the defect is parallel to the weld, the defect of the weld is an oblique defect for the spiral pipe. In the course of use, the principal stress direction of the steel pipe, that is, the equivalent defect length in the axial direction of the steel pipe is smaller than that of the straight seam pipe; secondly, since the pipeline steel is a rolled steel plate, the impact toughness has a large anisotropy.
The CVN value in the rolling direction can be three times higher than the CVN value perpendicular to the rolling direction. The main stress of the straight seam pipe is exactly perpendicular to the direction of the lowest impact resistance of the pipe, while the spiral pipe staggers the direction of the lowest impact resistance of the pipe, which turns the disadvantage of the long weld of the spiral pipe into an advantage.

Spiral submerged arc welded pipe (SSAW steel pipe) external thread display

Spiral submerged arc welded pipe (SSAW steel pipe) external thread display
Spiral submerged arc welded pipe (SSAW steel pipe) is the strip volume control when the forward direction and forming a molding pipe centerline angle (adjustable), side molding edge welding, the weld into a spiral, the advantage of the same specifications of the strip can beproduction of a variety of diameters of pipe, meet a wider range of raw materials, welds can avoid the main stress, the force is better, the disadvantage is poor geometry,the weld seam length compared to the straight pipe length, easy to produce cracks, pores, slag, welding and other welding defects side, welding stress was tensile stress state.General long-distance gas pipeline design specification spiral submerged arc welded pipe can only be used for Class 3, Class 4 area.
Foreign raw materials will be changed to improve this process steel, so that separate forming and welding, the welding and lean pre-, post-weld cold-expanding, then the quality of welding close to the UOE pipe, currently there is no such process,is the spiralFactory directions for improvement. "Natural Gas" is still used by the traditional spiral process of production, but the tube side of the expander.United States, Japan and Germany in general negative SSAW, that trunk should not use SSAW; Canada and Italy, some use SSAW, Russia, a small amount of use SSAW, and have developed a very strict additional conditions, due to historical reasons, most still use the main trunk domestic SSAW. LSAW pipe (LSAW) is a single plate as raw material, steel in the mold or molding machine pressure (volume) into the tube, using double-sided submerged arc welding method and Expanding from the produce.

Standard and Classfication of SSAW Steel Pipe

Classfication Standard Main Products
Line Pipe API 5L PSL1/2 Line pipe
Casing API 5CT/ ISO 11960 PSL1 Steel pipe for use as casing or tubing for wells of petroleum and natural gas industries
Steel Pipe for 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
Steel Pipe for Ordinary Structure 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

SSAW Steel Pipe inner anti-corrosion layer display

SSAW Steel Pipe inner anti-corrosion layer display

Usually welded pipes are used for the transportation of normally lower pressure fluids such as water, gas, air, oil and heating steam.
Ordinary carbon steel wire bushings (GB3640-88) are steel pipes used to protect electric wires in electrical installations such as industrial and civil buildings and installation machinery.
Straight seam welded pipe is a steel pipe whose weld is parallel to the longitudinal direction of the steel pipe. Usually divided into metric electric welded pipe, welded thin-walled pipe, transformer cooling oil pipe and so on.
Spiral submerged arc welded pipe (SY5036-83) for pressurized fluid conveying is a hot-rolled steel strip coil for tube blank, regular temperature spiral forming, welded by double-sided submerged arc welding, spiral seam steel pipe for pressure fluid conveying . The steel pipe has strong pressure bearing capacity and good welding performance. It is safe and reliable after various strict scientific tests and tests. The steel pipe has a large caliber, high conveying efficiency, and can save investment in laying pipelines. It is mainly used to transport oil and natural gas pipelines.
Spiral seam high-frequency welded pipe (SY5038-83) for pressurized fluid conveying is a hot-rolled steel strip coil for tube blank, which is often spiral-formed by high-frequency lap welding, and used for spiral conveying of pressurized fluid. High-frequency welded steel pipe. The steel pipe has strong pressure bearing capacity and good plasticity, which is convenient for welding and processing. After various strict and scientific inspections and tests, the use is safe and reliable, the steel pipe has large caliber, high conveying efficiency, and can save investment in laying pipelines. It is mainly used for laying pipelines for transporting oil and natural gas.

Chemical Analysis and Mechanical Properties of SSAW Steel Pipe

The raw material of the SSAW steel pipe includes steel coil, welding wire, flux. All of raw materials must be through strict physical and chemical maintenance before the investment.
Standard Grade Chemical Composition(max)% Mechanical Properties(min)
C Si Mn P S Tensile Strength(Mpa) Yield Strength(Mpa)
API 5CT h40 0.030 417 417
J55 0.030 517 517
K55 0.300 655 655
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
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

Spiral Seam Annealing Systems:

Offering all the basic features and benefits of Thermatool seam annealing systems designed for operation on longitudinally welded API pipe, Thermatool Spiral Seam Annealing systems, however, require the installation of specially "shaped" inductors.Thermatool designs and manufactures Spiral Seam Annealing systems for producers of SAW (submerged arc welded) API line pipe.
These are custom designed on CAD systems in order to precisely follow the helix angle for a specific pipe diameter.

Production process of SSAW steel pipe

Spiral steel pipe is a spiral seam steel pipe which is made of steel coiled coil as raw material, which is often heated and extruded and welded by automatic double wire double-sided submerged arc welding process.
Production process of SSAW steel pipe
Production process of SSAW steel pipe

  • (1) Raw materials are strip coils, welding wire, flux. Strict physical and chemical testing is required before input.
  • (2) The steel head and tail are butt jointed, and the single wire or double wire submerged arc welding is used, and the automatic submerged arc welding is used after the steel pipe is rolled.
  • (3) Before forming, the strip is leveled, trimmed, planed, surface cleaned and pre-bent.
  • (4) The electric contact pressure gauge is used to control the pressure of the cylinder on both sides of the conveyor to ensure the smooth conveying of the strip.
  • (5) Adopt external control or internal control roll molding.
  • (6) The weld gap control device is used to ensure that the weld gap meets the welding requirements, and the pipe diameter, the amount of misalignment and the weld gap are strictly controlled.
  • (7) Both internal welding and external welding are performed by single-wire or double-wire submerged arc welding by American Lincoln welding machine to obtain stable welding specifications.
  • (8) The welded seams are all inspected by online continuous ultrasonic automatic injury inspection to ensure the non-destructive testing coverage of 100% spiral welds. If there is a defect, the alarm is automatically alarmed and sprayed, and the production worker adjusts the process parameters at any time to eliminate defects in time.
  • (9) The steel pipe is cut into individual pieces by an air plasma cutting machine.
  • (10) After cutting into a single steel pipe, each batch of steel pipe shall be subjected to a strict first inspection system to check the mechanical properties, chemical composition, bonding condition, surface quality of the steel pipe and non-destructive testing to ensure the pipe making process. After that, it can be officially put into production.
  • (11) The part of the weld with continuous acoustic flaw detection mark, after manual ultrasonic and X-ray review, if it is defective, after repair, it will pass the non-destructive test again until it is confirmed that the defect has been eliminated.
  • (12) The tube of the butt weld of the strip and the joint of the butt joint intersecting the spiral weld are all inspected by X-ray television or film.
  • (13) Each steel pipe is subjected to hydrostatic pressure test and the pressure is radially sealed. The test pressure and time are strictly controlled by the steel pipe water pressure microcomputer detection device. The test parameters are automatically printed and recorded.
  • (14) Pipe end machining, so that the verticality of the end face, the groove angle and the blunt edge are accurately controlled.

Production Notes of SSAW Steel Pipe

SSAW steel pipe in the production process, we need to pay attention to a series of matters. Except for the following test items, according to the API standard and other relevant standards and the special requirements of some users, but also the need for steel, steel pipe and other tests Destructive tests, including physical and chemical properties of the raw materials into the plant sampling, visual inspection of 100% steel .
  • A. Oiled marking: steel after passing were oiled to prevent corrosion, and according to user requirements for marking.
  • B. Leveling Milling: The flat steel anvil machine so that the original curl, and then through the edge milling machine for two-sided steel milling, so as to meet the requirements of the plate width, plate edge parallelism and groove shape.
  • C. Shear molding: the steel plate production line along the outer edge of the spiral curl into a tube.
  • D. Butt cut: double-sided submerged arc welding using advanced technology to pre-welding, internal welding, outside welding. The welded steel pipe using a plasma-foot cut to specification length.

How to Increase the Stability of the SSAW Steel Pipe?

After the production of SSAW steel pipe, it should be stored.If we don’t do some measures to keep its stability, it will rust and be corroded. So we will talk about how to increase the stability of the spiral welded pipe today. Generally speaking, we have followed methods:
  1. Small and medium-sized steel, wire rod, rebar, steel pipe with medium diameter, wire and wire rope, etc., can be stored in well-ventilated shed, but must put covering in the upper part of the goods and underlay at the bottom of the goods.
  2. Some small steel shape, sheet steel, steel strip, silicon steel sheet, small diameter or thin-walled steel pipe, all kinds of cold-rolled or cold-drawn steel and the metal products with high prices and easy-to-corrode can be stored in warehouse.
  3. The ground or warehouse to store spiral steel pipe should choose the place where is orderly and clean, and it is easy to fluently drain away water. It should stay away from the factories and mines that products harmful gases or dust. We also need to remove the weeds and all debris to keep the steel clean on the ground.
  4. Large-scale structural steel, steel rail, large diameter steel pipe, forgings, etc. can be opened stack.
  5. In the warehouse, SSAW steel pipe should not be stacked with the acid, alkali, salt, cement and other materials that have corrodibility on steel together. Different varieties of steel should be stacked separately, to prevent confusion and prevent contact corrosion.

Advantages of SSAW steel pipe:

  1. High production efficiency. On the one hand, the wire length is shortened, the current and current density are improved, therefore, the penetration depth of the arc and the deposition efficiency of the welding wire are greatly improved. Generally, single-sided melting depth of can be up to 20mm if do not open the groove. On the other hand, due to thermal insulation of flux and slag, the arc basically has no loss of heat radiation, welding spatter is also few. Although the heat loss for melting the flux is increased, the overall thermal efficiency is still greatly increased.
  2. High quality of weld seam. The protective effect of the slag from the air is good, the welding parameters can be stabilized by automatic adjustment, the requirement of the welder’s technical level of is not high, the composition of weld seam is stable and the mechanical performance is better.
  3. Good working conditions. In addition to reducing the labor intensity of manual welding operations, it does not have arc radiation, which is the unique advantage of submerged arc welding.

Disadvantages of SSAW steel pipe:

The flexibility of submerged arc welding is not as good as manual welding, it is generally only suitable for the weld seam that in horizontal position or small gradient. Workpiece edge preparation and assembly quality requirements are higher, which is cost more working time. Due to using submerged arc welding, we can not see the bath and weld formation process, so the welding specification must be strictly controlled.

How to Identify The Quality of SSAW Steel Pipe?

Poor quality SSAW steel pipe is easy to produce burrs, because some inferior manufacturers have tinpot equipment. Prime Steel Pipe is positioned as an excellent steel pipe manufacturer and exporter for carbon steel pipe, we have over 20 years to manufacture SSAW steel pipe. So the SSAW steel pipe produced by Prime Steel Pipe all have the best quality, you can trustingly choose our spiral welded pipe. Generally, burrs will scratch the appearance of SSAW steel pipe and is easy to fold, the tendons are thin and low. and often appear full of dissatisfaction with the phenomenon. The reason is that the manufacturers to achieve a large negative tolerance, waste a few Road before the reduction of the amount of large, iron type is small, well filled dissatisfaction. Prone to crack. The reason is that the blank is the adobe, the adobe pores and more, adobe in the cooling process due to the role of thermal stress, cracks, after rolling there are cracks.
SSAW steel pipe regularly appear quality problems in the production and use. So we need to identify the quality of SSAW steel pipe, in accordance with a certain way and performance testing, can be used in the actual use of an important role. Then how to identify fake spiral steel pipe method: there often are pimple phenomenon in appearance. In general, the overall effect of weighing will be better, mainly taking into account the cumulative error and probability theory of this problem. Pitted surface is due to the serious wear and tear caused by the uneven appearance of spiral steel pipe irregular irregular flaws. As the shoddy SSAW steel pipe manufacturers to pursue profits, often rolling the most rolling standard. Appearance easy to produce scar.
The end of top crops is smooth and tidy, composition of high-quality SSAW steel pipe is evenly. The pseudo-poor material due to poor quality, cutting the end of the face often have the phenomenon of meat, that is uneven, and no metallic luster. And because the false product manufacturers cut off the small head, head and tail will appear big ears. The size of the inner diameter fluctuates greatly. The reason is that l steel temperature is unstable yin and yang face. The composition of the steel is not uniform. Folding is the appearance of spiral steel pipe formed a variety of polylines, this defect often runs through the entire product longitudinal. The reason for the folding is due to the pursuit of high efficiency of the manufacturers, the amount of depression is too large, the occurrence of ear, the next rolling when the folding, folding products will crack after bending, thick-walled spiral steel strength decreased.
The temperature of the pseudo-material rolling is not standard, no metallic luster. A pale red or similar pig iron color. Cross section is oval. The reason is that manufacturers in order to save information, waste roll two before the pressure is too large, the strength of this rebar greatly reduced, and does not meet the specifications of the size of rebar. There are two reasons:. Fake spiral steel pipe material is not uniform, more impurities. Pseudo-poor material manufacturers guide equipment is simple, easy to stick steel, these impurities bite into the roll after the easy to produce scar.

How to Test the Stress Resistance of SSAW Steel Pipe?

The large-diameter ssaw steel pipe factory needs to test the product after the production is completed, especially its compressive capacity, because we usually use it in the ground when it is used, so it is required to have good pressure resistance, then how to test it.
Firstly, both ends of the tested steel pipe are sealed by the end seal device and low pressure water is injected. During the water injection process, the air in the pipe is exhausted through the exhaust valve. After the low pressure water is filled, the high pressure water is injected into the pipe through the pressurizing device to pressurize the gas. The specified test pressure is reached. After the specified test pressure is reached, the pressure is maintained for a predetermined period of time. If there is no leakage or deformation, the pressure is released.
Products that have been tested for resistance to stress can be used to ensure the effectiveness of the spiral tube. Of course, it is necessary to carry out relevant anti-corrosion measures according to its use environment to ensure its use effect and longevity.
Difference between ERW, SSAW, LSAW
Steel pipe for pipe technology, can be divided into (SML), mainly as the Oilfield internal transportation pipeline and small-diameter high-pressure natural gas pipeline, used for a small number of long-distance gas pipeline, the vast majority of long-distance pipeline with Direct seam high frequency (ERW), spiral submerged arc (SSAW), LSAW three (LSAW).
Here are comparisons of technological features and performance of these pipes:
ERW pipes means Electric Resistance Welded Pipes.
High frequency straight seam welding (ERW) method is divided into two forms of induction welding and contact welding, hot-rolled wide volume as raw material, pre-curved, continuous molding, welding, heat treatment, sizing, straightening, cutting, etc. process, compared with the spiral weld short, high dimensional accuracy, uniform thickness, surface quality, pressure advantages, but the drawback is that only the production of small and medium-caliber thin-walled tube, weld easy to produce gray leaf spot, not fusion ditch-like corrosion defects. Wider application areas of city gas, crude oil transportation.
Spiral submerged arc welding(SSAW)
SSAW pipe is its forward direction and forming tube centerline hose reel molding angle (adjustable), side molding edge welding and weld them into a spiral.
Spiral submerged arc pipe (SSAW pipe) is its forward direction and forming tube centerline hose reel molding angle (adjustable), side molding edge welding and weld them into a spiral, the advantage of the same specification to produce a variety of diameter sizes steel pipe, raw materials to adapt to a wider range, the weld can avoid the main stress force better, the disadvantage is the poor geometry of the weld length compared to the long straight seam pipe, prone to cracking, porosity, slag, welding partial welding defects such as welding stress was tensile stress state. General Oil and Gas Pipeline design specification spiral submerged arc can only be used for Class 3, Class 4 regional.
LSAW (LSAW) in leaflets plate as raw material, the steel plate in the mold or molding machine pressure (volume) into using double-sided submerged arc welding and flaring from production. A wide range of the finished product specifications, weld toughness, ductility, uniformity and dense, with a large diameter, wall thickness, high pressure resistance, low-temperature corrosion resistance, etc.. Required steel pipe in the construction of high-strength, high toughness, high-quality long-distance oil and gas pipelines, mostly large diameter thick wall LSAW.
API standard provisions, in the large-scale oil and gas pipelines, when 1, Class 2 areas through the alpine zone, the bottom of the sea, the city densely populated area, LSAW only applied specifically casts. Molding can be divided into:
UOE: leaflets steel plate after the edge preflex, after U molding, O forming within welding, the outer welding, mechanical cold expanded diameter process;
JCOE: Press "JCOE" pre-welding, forming, welding after cold expanded diameter process.
How to Choose the SSAW Steel Pipe?
Usage of SSAW steel pipe is relatively high, the application is very wide, it should be how to choose before in the selection to pay attention to quality.
The first method is a more professional detection method, that is, by the strength of the pressure vessel to be detected. Commonly, we use atmospheric pressure and water pressure to detect, in this way can detect the working conditions of the SSAW steel pipe in the pressure working environment, but also to detect the tightness of the spiral steel pipe, generally take the atmospheric pressure detection, because such security Relatively high, and if the water vapor pressure through the test, then the need to remove the spiral pipe after the water, too much trouble.
The second method is also relatively simple, that is, through the surface of observation. With the naked eye found in the spiral steel pipe in the welding and size of the problem, if necessary, you can also use the standard sample and the products to be compared to find the problem. In general, formal steel pipe company in the production is relatively perfect, on the other hand to beat the metal pipe, if the sound is very crisp and the echo is not very dirty, then the name is the latest selection of steel pipe, rather than scrap steel recycling.
These two methods are commonly used, we can choose a way to test, more secure way is the best to the regular manufacturers, can reduce the use of the process of abuse.
Source: China Steel Pipe Manufacturer – Cangzhou Datang steel pipe company (

how to contact us?


Cangzhou Datang Steel Pipe Co., Ltd All Right Resevered.