What is SSAW steel pipe?

What is SSAW steel pipe?

Spiral submerged arc welded steel pipe refers to a metal pipe with a spiral seam welded by a submerged arc welding process.

1 Application 2 Characteristics 3 Production technology
4 Raw material 5 Process performance 6 Standard classification

1 Application of SSAW steel pipe

Generally used in: welding into pipes for fluid transport, metal structures, pile foundations, etc.
The products are widely used in water supply engineering, petrochemical industry, chemical industry, electric power industry, agricultural irrigation, urban construction, and are one of the 20 key products developed in China. For liquid transportation: water supply and drainage. For gas transportation: gas, steam, liquefied petroleum gas. For structural use: for piling pipes, for bridges; for piers, roads, building structures, etc.

2 Characteristics of SSAW steel pipe

Spiral submerged arc (SSAW) 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. Raw materials instead will this process improvement abroad steel plate forming and welding separate pre-weld and lean and, after welding cold flaring near UOE pipe welding quality, currently no such process of plant improvement direction. “West-East” still is a traditional craft production, just expanded diameter of the pipe end. United States, Japan and Germany, the overall negative SSAW, think the mainline unfit for use SSAW; Canada and Italy part SSAW Russian small amount of SSAW, and have developed a very strict supplementary conditions, due to historical reasons, the majority of the domestic main trunk or use SSAW.

It is possible to produce welded pipes with large diameters with narrow blanks, and it is also possible to produce welded pipes with different pipe diameters with blanks of the same width. The production cost is low, the process is simple, and it is easy to produce large diameter pipes. Large-diameter welded pipes are mostly made by spiral submerged arc welding.

3 Production technology

Spiral Submerged-arc Welded steel pipe technological process

Spiral welded pipe production by submerged arc method is based on using tandem welding technique for joining inside and outside coil edges, which have been trimmed and beveled by carbide milling for high quality weld structure.

Spiral Seam Annealing Systems:

outside diameter control - What is SSAW steel pipe? x ray testing online - What is SSAW steel pipe? hydrostatic testing - What is SSAW steel pipe?
Outside Diameter Control X-Ray Testing Online Hydrostatic Testing

Thermatool designs and manufactures Spiral Seam Annealing systems for producers of SAW (submerged arc welded) API line pipe.

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.

These are custom designed on CAD systems in order to precisely follow the helix angle for a specific pipe diameter.

Spiral Submerged-arc Welded steel pipe technological process

There are nine modernized product lines in our company with the yield capacity of 1000 thousands tons of B-X80 steel pipe of φ219-φ3200mm, WT5-30mm.

ssaw pipe process - What is SSAW steel pipe?

Listing some notes You must know

  • Oiled marking: Steel after passing wrer oiled to prevent corrosion,and according to user requirements for making.
  • Leveling Milling: The flat steel anvil machine so that the origal curl,and then thouth 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.
  • Shear molding: The steel plate production line along the outer edge of the spiral curl into a tube.
  • Butt cut: Double-sided submerged arc welding using advanced technology to pre-welding,internal welding,outside wilding.The welded steel pipe using a plasma-foot cut to specification length.

4 Raw material

  • Q235-Q345
  • L175-L485
  • SS400
  • 16Mn
  • L290-L360
  • X42, X46, X70, X80
  • or according to the customer’s requirements.

The raw material of ssaw steel pipe is a hot rolled plate, which is a strip or a coil.
Hot-rolled steel sheets, that is, hot-rolled steel-rolled steel sheets or steel strips, commonly known as hot plates, are usually also written as zigzags, such as hot-rolled sheets, but all refer to the same hot-rolled sheet. Refers to a steel plate having a width greater than or equal to 600 mm, a thickness of 0.35-200 mm, and a steel strip having a thickness of 1.2-25 mm. The cold-rolled sheet is obtained by rolling a hot rolled coil as a raw material at a recrystallization temperature at room temperature.
The difference between hot rolled sheet and cold rolled sheet:
Hot-rolled steel sheets are divided into structural steel, low-carbon steel, and welded steel, and then you can find the steel you need according to various steels, and check the density and composition of specific steels.
Hot-rolled steel sheets have low hardness, easy processing and good ductility.
The cold rolled sheet has high hardness and high relative strength of processing.

5 Spiral submerged arc welding process performance:

  • (1) raw materials that strip, wire, flux. Must go through rigorous testing before being put into the physical and chemical.
  • (2) strip head and tail docking, using single or double wire submerged arc welding, in rolled steel by automatic submerged arc welding.
  • (3) Before molding, the strip after flattening, cutting, trimming, planing, surface cleaning and transportation to the curved edge treatment. 
  • (4) the use of electrical contacts on both sides of the conveyor control the pressure cylinder pressure to ensure the smooth delivery of the strip. 
  • (5) the use of internal or external control roll forming. 
  • (6) the weld gap control device to ensure that the weld gap to meet the welding requirements, diameter, volume and the wrong side of the weld gap have been strictly controlled. 
  • (7) the welding and soldering are used outside the United States Lincoln welding machine for single or double wire submerged arc welding, to obtain stable welding specifications. 
  • (8) After welding the weld line continuous ultrasonic injury checked to ensure 100% coverage of non-destructive testing of spiral weld. If defective, automatic alarm and spraying tags, production workers so adjusting the process parameters, and remove defects. 
  • (9) the use of air plasma cutting machine to cut a single tube. 
  • (10) cut into a single pipe, the first three of each batch of steel to carry out strict inspection system, inspection of weld mechanical properties, chemical composition, fusion status, steel surface quality and after NDT inspection to ensure that the process pipe after passing to formally put into production. 
  • (11) there is a continuous sonic flaw marks the site of the weld, manual ultrasonic and X-ray review, if there are defects after repair again after destructive testing until confirmation defect has been eliminated. 
  • (12) strip on the spiral weld seam and intersects with D-type connector where the pipe all through the X -ray television or film examination. 
  • (13) each pipe hydrostatic test pressure radial seal. Test pressure steel pipe pressure and time by computer testing device strictly controlled. Test parameters are automatically printed record. 
  • (14) pipe end machining, so that the end vertical, blunt edge bevel and accurate control.

6 Standard classification

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

Chemical Analysis and Mechanical Properties of SSAW Steel Pipe

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

Pipe End: 

square ends (straight cut, saw cut, and torch cut). or beveled for welding, beveled, 

Surface:

Lightly oiled, Hot dip galvanized, Electro galvanized, Black, Bare, Varnish coating/Anti rust oil, Protective Coatings (Coal Tar Epoxy,  Fusion Bond Epoxy, 3-layers PE)

Packing:

Plastic plugs in both ends, Hexagonal bundles of max. 2,000kg with several steel strips, Two tags on each bundle, Wrapped in waterproof paper, PVC sleeve, and sackcloth with several steel strips, Plastic caps.

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:

The ssaw steel pipe shall be the first to be in the performance test, the flattening test and flare test before leaving the factory, and shall meet the requirements specified in the standard.
Physical method testing: The physical testing method is a method of measuring or testing using some physical phenomena. Inspection of the internal defects of materials or workpieces is generally carried out by means of non-destructive testing. Non-destructive testing includes ultrasonic flaw detection, The singularity of the surface, that is, in the appearance inspection. The appearance inspection of the welded joints is a simple and widely used inspection method. It is an important part of the inspection of finished products In the case of the thin and is a possibility of defects inside the weld.
Non-destructive testing, repair welding of steel pipes, steel-to-head welds and hoop seams shall bet to X-ray or ultrasonic inspection. For the spiral weld of the steel direction for the transportation of combustible ordinary fluids, 100% SX Ray- ultrasonics shall be carried out. X-rays shall be applied to the spiral welds of steel pipes used for the transportation of common fluids such as water, sewage, air and heating steam. 
The strength test of pressurized containers: In addition to the sealing test, the pressure vessel of the fluid tests and air pressure tests. There are two types of hydraulic tests and air pressure tests. The air pressure test is more sensitive and speedy than the water pressure test. At the same time, the tested product does not need to be drained, which is especially suitable for products with difficult drainage. The conducting test, the corresponding safety technical measures must be observed to prevent accidents during the test.
Density test: In the case of a welded container for storing liquid or gas, the indentation of the weld is not dense, such as penetrating cracks, pores, slag inclusions, incomplete penetration and loose structure, etc., which can be found by a compactness test. The methods of compactness test include: kerosene test, water carrying test, water flushing test, etc.
The hydrostatic test requires that each steel pipe should be hydrostatically tested without leakage. The test pressure is calculated according to the test: P=2ST/D, the test stress Mpa of the S-hydrostatic test, and the test stress of the hydrostatic test should be corresponding steel strip standard specifies 60% of the minimum yield (Q235 is 235Mpa). Regulating time: D<508 test pressure holding time is not less than 5 seconds; D≥508 test pressure holding time is not less than 10 seconds.

Ultrasonic Test System for SSAW Pipe Weld Seam

Ultrasonic inspection of seamless pipes - What is SSAW steel pipe?
Ultrasonic inspection

Widely preferred longer lengths up to 18,5 m. considerably decreases the cost of pipeline construction resulting in less number of girth welds compared to shorter pipe lengths.

When weld ultrasonic testing, in order to track the weld automatic tracking, the probe is always in the frame just above the weld. The system uses laser vision technology to detect traces of the weld, using IPC and motion control components work together to reach out manual control, automatic track welds, adjust the probe holder the right destination location.

Laser weld ultrasonic testing automatic tracking system consists of a laser vision sensor, data processing means for controlling the composition and executing agencies. Laser vision sensor comprises a CCD camera and a semiconductor laser; data processing agencies, including image acquisition card, and industrial control computer; including PLC control mechanism and stepper motor drives; positioning actuator includes a skateboard, a stepper motor and connected institutions.

System in real time using laser vision sensor weld image; industrial control computer through a dedicated software processing to obtain the image feature points to calculate the deviation of the weld, width, and other parameters the wrong side, and then send control commands through PLC, the drive to drive a stepper motor driven skateboard and probe holder back to the correct position. Laser weld ultrasonic inspection system in the design and manufacture of automatic tracking process to fully consider the scene, laser vision sensor uses a high anti-jamming equipment , stable and reliable; data processing bodies and control mechanisms are used for industrial equipment, common good, low failure rate, easy maintenance; executive body of imported ball screw and linear guide rail, high precision, durable, good dustproof performance.

For spiral weld ultrasonic inspection, testing is now more commonly used method, which is to weld pipe arranged on both sides of a number of ultrasonic shear wave probes, parallel motion detection pipe weld seam parallel or perpendicular to the seam weld defects.

Lifetime of SSAW Steel Pipe

SSAW steel pipe itself has no life limit, and the service life is mainly related to the operating environment and production process. Spiral steel pipe operating environment is relatively poor In order to extend the service life, the outer wall and inner diameter of the steel pipe are preserved.
Anti-corrosion steel pipe refers to a steel pipe that has been treated by anti-corrosion technology and can effectively prevent or slow down the corrosion phenomenon caused by chemical or electrochemical reaction during transportation and use. The anti-corrosion steel pipe can effectively prevent or slow down the corrosion and prolong the service life of the steel pipe and reduce the running cost of the steel pipe.
There are many steel pipeline anti-corrosion coatings in China, such as petroleum asphalt, PE jacket and PE foam jacket, epoxy coal tar pitch, coal tar enamel, epoxy powder and three-layer composite structure, and epoxy coal tar pitch cold-wrapped belt (PF type). , rubber-plastic epoxy coal tar cold tape (RPC type), etc., the most widely used pipe anti-corrosion methods are three-layer PE composite structure, single-layer powder epoxy, PF cold-wrapped tape, RPC-type cold Wrap.

How To Effectively Carry Out SSAW Steel Pipe Connection Work

The connection method of ssaw steel pipe is generally welded, because the welded pipe is relatively low in cost. Some projects will also use other connection methods due to factors such as construction period, construction conditions, geographical environment, etc., such as: screw connection, flange Connection, socket connection, groove connection, etc. Let’s talk about the characteristics of other connection methods:

  1. Flange connection Generally, the flange connection speed is fast, the construction is convenient, and the tool is simple. However, in terms of safety and sealing, most of the engineering requirements cannot be met. Generally, the pipeline with low pressure is often used for the connection. Such as mud pipes, etc.
  2. Groove connection: also known as clamp connection technology, has become the first technology of current liquid and gas pipeline connection. Although this technology is developed later in China, due to its advanced technology, it is quickly Received by the domestic market. The application of the grooved pipe joint technology makes the complicated pipe connection process simple, fast and convenient. Make pipe connection technology a big step forward. The groove connecting pipe fittings comprise two major types of products:
  • pipe joint with sealing function, rigid joint, flexible joint, mechanical tee and grooved flange;
  • pipe joint with transition function, elbow, tee, Four-way, reducer, blind plate, spiral welded pipe, etc. The groove connecting pipe joint for sealing is mainly composed of three parts: a sealing rubber ring, a clamp and a locking bolt. 

The rubber sealing ring located on the inner layer is placed on the outer side of the pipe to be connected, and is matched with the pre-rolled groove, and then the clamp is fastened on the outside of the rubber ring, and then fastened by two bolts. Due to the unique sealable structural design of the rubber seal ring and the clamp, the groove joint has good sealing property, and the sealing property is correspondingly enhanced as the fluid pressure in the pipe is increased.
The groove connection makes the pipe connection operation simple, is conducive to construction safety, good system stability, convenient maintenance, labor saving and time saving, and therefore has good economic benefits. With the clamp connection, although the price of the individual fittings of the clamp is relatively high, the overall benefit of the entire pipe network installation is higher than that of the flange connection.

The clamp pipe joint connection is an advanced pipe connection method, that is, it can be set or buried, that is, there are steel joints and flexible joints. Therefore, it has a wide range of applications. It can be used in fire water systems, air conditioning hot and cold water systems, water supply systems, petrochemical pipeline systems, thermoelectric and military pipeline systems, sewage treatment pipeline systems, etc.

How to buy welded steel pipes?

There are many types of welded steel pipes, such as wire rods, spiral welded steel pipes, Spiral submerged arc welded steel pipe, straight seam welded steel pipes, etc., which are the best-selling and most popular welded steel pipes in the market. Take the spiral welded steel pipe, how can we buy a good quality and affordable product when we buy it? In fact, there are skills to follow. We are not blindly purchasing. It is believed that the products with beautiful appearance are also good in quality. This concept has been in the minds of some of our consumers. Deep-rooted, but in fact it is very wrong.
How to choose to purchase a spiral welded steel pipe brand product with high quality, low cost and high quality service. Nowadays, there are many brands of spiral welded steel pipe in the market. How can we choose the most suitable spiral welded steel pipe brand products? Through this article, the spiral welded steel pipe brand is purchased as a comprehensive guide for the majority of consumers or friends who are about to face the purchase problem.
Just like eating in a restaurant, the more people eat the restaurant, it proves that the food in the restaurant is delicious. I believe that the eyes of the people are bright. When purchasing spiral welded steel pipe products, they are buyers, wholesalers and individuals. You must also choose the brand spiral welded steel pipe products as you like to eat, and you can purchase local brands according to the following points.

  1. Find a manufacturer of spiral welded steel pipe brands that is trusted by local people.
  2. Collect the list of local spiral welded steel pipe brand manufacturers, and sort them by category (according to the manufacturer’s entity size, production equipment, production personnel, production management system), and you don’t need to collect them as key points.
  3. Compare local brand, user group trust and consumption patterns.

A comprehensive understanding of the above three points, and is suitable for some data surveys for comparison.
Spiral welded steel pipes should be qualified products with the manufacturer’s name, brand and specifications. The water supply pipe shall be threaded. The welded steel pipe shall have exposed threads at its joint. After installation, it shall be fixed by pipe clamp in time. The pipe and pipe fittings or valves shall be firmly connected without any looseness. After the spiral welded steel pipe is installed, it is checked by water, and visual inspection and hand feeling are used to check for leaks. Check whether all the faucets and valves are installed flat, whether the flexible straight seam welded steel pipe is opened, whether the water is unblocked, and whether there is leakage. Check if the water meter is working properly. For some special cases, be careful to avoid accidents. For example, the pipe is very long, connected to the kitchen and bathroom, or to the balcony, the spiral welded steel pipe should pass through the living room or room. Since the pipe is not buried in the wall or laid under the floor, if there is a problem, the consequences are very serious, so there is no joint in the middle. And to properly enlarge the diameter of the pipe to avoid blockage. Hot water pipes shall not be galvanized iron pipes to prevent corrosion of pipes and scale, and heat insulation measures shall be taken.

Source: China SSAW Steel Pipe Manufacturer – Yaang Pipe Industry Co., Limited (www.ugsteelmill.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

If you want to have more information about the article or you want to share your opinion with us, contact us at sales@ugsteelmill.com

Please notice that you might be interested in the other technical articles we’ve published:

References:

  • https://www.yaang.com
  • https://www.steeljrv.com/how-to-buy-welded-steel-pipes.html

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