DSAW pipe

Double Submerged Arc Welded (DSAW) steel pipe is available in straight and spiral welded formats and used in a variety of applications.

Please send your inquiry by sales@sunnysteel.com

Category: Weld steel pipe Tag: Type of welded pipe

Description

Double Submerged Arc Welded (DSAW) steel pipe is available in straight and spiral welded formats and used in a variety of applications. The submerged welding process protects the steel from contamination of impurities in the air.

DSAW pipe can be specified in very large diameter and to exact inside or outside dimensions. Spiral Welded steel pipe is distinguished by the manufacturing process that results in a spiral DSAW seam the length of the pipe to lengths of 155 feet.

The manufacturing of Double Submerged Arc Welded Pipe involves first forming steel plates into cylindrical shapes. Then the edges of the rolled plate are formed so that V-shaped grooves are formed on the interior and exterior surfaces at the location of the seam. The pipe seam would then be welded by a single pass of an arc welder on the interior and exterior surfaces. The welding arc is submerged under flux. What can be known as an advantage of this process is that welds would penetrate 100% of the pipe wall and produce a very strong bond of the pipe.

Full Supply Ltd have been supplying EFW Electric Fusion Welded Pipe for many years.

We supply DSAW Pipe to the folowing industries on a global scale:

Oil Industry
Gas Industry
Filtration Industry
Refrigeration Industry
Refining Industry
Petrochemical Industry
Offshore Industry

How is the double-sided submerged arc welding thick-walled spiral steel pipe made?

Spiral steel pipe is a spiral seam steel pipe made of strip steel coils as raw materials, often extruded and formed by automatic double-wire double-sided submerged arc welding.

(1) Raw materials are strip steel coils, welding wires, and fluxes. Strict physical and chemical tests are required before investment.
(2) Butt joint of strip steel head and tail, adopt single wire or double wire submerged arc welding, after coiling into steel pipe, adopt automatic submerged arc welding repair welding.
(3) Before forming, the strip undergoes leveling, edge trimming, edge planing, surface cleaning and conveying, and pre-bending treatment.
(4) The electric contact pressure gauge is used to control the pressure of the cylinders on both sides of the conveyor to ensure the smooth conveying of the strip.
(5) Adopt external control or internal control roll forming.
(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 all strictly controlled.
(7) Both internal welding and external welding adopt the American Lincoln electric welding machine for single-wire or double-wire submerged arc welding to obtain stable welding specifications.
(8) The welded seams after welding are all inspected by an online continuous ultrasonic automatic flaw instrument, which guarantees 100% non-destructive testing coverage of spiral welds. If there is a defect, it will automatically alarm and spray the mark, and the production workers can adjust the process parameters at any time to eliminate the defect in time.
(9) Use an air plasma cutting machine to cut the steel pipe into individual pieces.
(10) After cutting into single steel pipes, the first three steel pipes of each batch shall be subject to a strict first inspection system to check the mechanical properties, chemical composition, fusion status of the welds, the surface quality of the steel pipes, and pass non-destructive inspections to ensure the pipe manufacturing process Only after it is qualified can it be officially put into production.
(11) The parts with continuous sonic flaw detection marks on the weld are re-examined by manual ultrasonic and X-ray. If there are defects, after repairing, they will go through non-destructive inspection again until the defects are confirmed.
(12) The pipes where the strip butt welds and the D-shaped joints intersecting the spiral welds are all inspected by X-ray television or filming.
(13) Each steel pipe undergoes a hydrostatic pressure test, and the pressure adopts a radial seal. The test pressure and time are strictly controlled by the steel pipe hydraulic microcomputer detection device. The test parameters are automatically printed and recorded.
(14) The pipe end is mechanically processed to accurately control the verticality, bevel angle, and obtuse edge of the end face.

Spiral double welding pipe process

Double submerged arc welded spiral steel pipe with its high pressure capacity, small resistance, low temperature resistance, corrosion resistance, easy installation and maintenance, etc., is more and more oil and gas, slurry transportation, urban construction and other industries welcome.

Spiral double welding pipe process

I. double submerged arc welding process, the plate deformation uniformly small, residual stress, surface does not produce scratches. Processing of pipe diameter and wall thickness of the pipe sizes range, greater flexibility, especially in the production of high-grade steel thick-walled steel pipe, large diameter thick wall pipe has the incomparable advantage of other technology, to meet the users in pipe size requirements;

Ⅱ. Presoldering outside welding (the fine welding) the process can be implemented in the best position welding, less prone to the wrong side of the welding partial and incomplete penetration defects such as welding quality, easy to control;

Ⅲ. Overall mechanical enlarged diameter, which can effectively improve the dimensional accuracy of a steel pipe, and improve the distribution state of the stresses in the steel pipe, thus avoiding the damage caused due to stress corrosion, is also conducive to the welded construction of the scene;

Ⅳ. 100% quality check on the steel, so that the whole process of pipe production are effective detection, monitored, to ensure the product quality of the SAW pipe;

Ⅴ. Entire production line equipment have networked with a computer data acquisition system to realize the real-time transmission of data, the quality of the technology in the production process parameters and quality indicators adopted by the central control room.

Welding advantages of double submerged arc welded straight seam steel pipe

Double submerged arc welded straight seam steel pipe is a new welding method invented in 1940, it is the same place and the front of the manual welding it or slag protection, but this residue is not the electrode coating, but melting out welding flux.

Flux system consists of a funnel filled with flux transported through a pipeline to the front to be welded. The second difference is not electrode, wire, because the wire can be continuously sent to; electrode, we burn an electrode must have a welding rod head gave throw, and the operation is stopped, and then change electrode welding.

After the wire is changed, with a means to send the wire and the wire for rent, gave continuous welding wire, welding wire is continuously fed, covered with a granular flux can be melted under the ignition of the arc, the welding wire, base material and part of the melting and evaporation of the flux constitute a cavity arc inside the cavity stable combustion, it called submerged arc welding. The arc is buried in the cavity inside.

The advantages of the double submerged arc welded

First: it is completely automated.
Second: it is carried out under the submerged arc welding, the heat exchange and protection performance is relatively strong, relatively high welding quality;
Third: submerged arc welding arc buried under the flux, so it can be used high current, high welding efficiency, the ongoing West-East Gas Pipeline project in our country recently.

Pipe is a high-strength steel, this first prefabricated section of pipe at the factory inside, and then get on the site, field welding, the welding process is the use of this pipeline in the factory to make a submerged arc welding, submerged arc welding has developed into a double wire submerged arc welding, as well as multi-wire submerged arc welding, to further improve the efficiency.

Standard

Welded pipes specification and size

Product Name	Executive Standard	Dimension (mm)	Steel Code / Steel Grade
Electric-Resistance-Welded Steel Pipes	ASTM A135	42.2-114.3 x 2.11-2.63	A
Electric-Resistance-Welded Carbon Steel and Carbon-Manganese Steel Boiler and Superheater Tubes	ASTM A178	42.2-114.3 x 2.11-2.63	A, C,D
ERW and Hot-dip Galvanized Steel Pipes	ASTM A53	21.3-273 x 2.11-12.7	A, B
Pipes for Piling Usage	ASTM A252	219.1-508 x 3.6-12.7	Gr2, Gr3
Tubes for General Structural Purpose	ASTM A500	21.3-273 x 2.11-12.7	Carbon Steel
Square Pipes for General Structural Purpose	ASTM A500	25 x 25-160 x 160 x 1.2-8.0	Carbon Steel
Mechanical tubing	ASTM A513	21.3-273 x 2.11-12.7	carbon and alloy steel
Screwed and Socketed Steel Tubes	BS 1387	21.4-113.9 x 2-3.6	Carbon Steel
Scaffolding Pipes	EN 39	48.3 x 3.2-4	Carbon Steel
Carbon Steel Tubes for General Structure Purpose	JIS G3444	21.7-216.3 x 2.0-6.0	Carbon Steel
Carbon Steel Tubes for Machine Structure Purpose	JIS G3445	15-76 x 0.7-3.0	STKM11A, STKM13A
Carbon Steel Pipes for Ordinary Piping	JIS G3452	21.9-216.3 x 2.8-5.8	Carbon Steel
Carbon Steel Pipes for Pressure Service	JIS G3454	21.7-216.3 x 2.8-7.1	Carbon Steel
Carbon Steel Rigid Steel Conduits	JIS G8305	21-113.4 x 1.2-3.5	G16-G104, C19-C75, E19-E75
Carbon Steel Rectangular Pipes for General Structure	JIS G3466	16 x 16-150 x 150 x 0.7-6	Carbon Steel

Coating

Pipeline coating is the most consistent and successful solution for protecting ERW pipes from corrosion, from moisture, other harmful chemicals.

Anti-corrosion steel pipe is processed through the preservation process, which can effectively prevent or slow down the process in the transport and use of chemical or electrochemical corrosion reaction of steel pipe.

Therefore pipe anti-corrosion layer is an important barrier to prevent soil erosion. A well-known foreign scholar put forward” 3PE france protective layer”, so far, anti-corrosion methods is widely used.

Coated pipes offer high resistance to corrosion on pipes and provide many benefits such as:

1. Increased Flow Capacity – A coating on pipes helps provide a smoother surface thus improving gas and liquid flow within pipes.

2. Reduced Cost – The pipeline coating increases the pipes durability so they can be deployed with minimum maintenance cost even in the harshest environments.

3. Lower energy usage – Various studies have shown that pipelines that are internally coated use less energy for pumping and compression of products through pipes. This helps in increased saving over time.

4. Clean delivery of products – The inhibitors used for the protection products can also be minimized by the use of coated pipes for delivery of products.

Thus, coating of pipelines can help you in reducing your maintenance cost and at the same time providing a corrosion free reliable protection.

Basic functions of erw pipe coating

making the surface of ERW steel pipes free from electrochemical corrosion of the soil medium, the basic physics of bacterial corrosion protection.
resisting the move of the soil medium creep stress, static stress and abrasion force method and structure of the basic machinery protection.

The basic principles of urban gas pipeline coating selection:

good insulating and mechanical properties;
good resistance to cathodic disbondment performance;
good resistance to water, gas permeability;
good chemical resistance soaking performance and anti-aging properties;
resistance to low temperature and high temperature performance;
easy mending and mending;
at reasonable prices.

Types of coating:

Coating Specifications

2.1.External Coating

2.1.1 External Epoxy Coating

API RP 5L2 Recommended Practice for Internal Coating of Line Pipe for Non-Corrosive Gas Transmission Service.
CAN/CSA-Z245.20 Standard for External Fusion Bond Epoxy Coating for Steel Pipe
AS 3862 Standard Specification for External Fusion-Bonded Epoxy Coating for Steel Pipes
AWWA C210 Standard for Liquid-Epoxy Coating Systems for the Interior and Exterior of Steel Water Pipelines
AWWA C213 Standard for Fusion Bonded Epoxy Coating for the Interior and Exterior of Steel Water Pipelines.
DEP 31.40.30.32-Gen TECHNICAL SPECIFICATION FOR EXTERNAL FUSION-BONDED EPOXY POWDER COATINGFOR LINE PIPE
NFA 49-710 Standard Specification for External FBE layered Coating
ISO 21809-2:2007, Petroleum and natural gas industries-External coatings for buried or submerged pipelines used in pipeline transportation systems-Part 2:
Fusion-bonded epoxy coatings
NACE RP0394 – National Association of Corrosion Engineers Standard Recommended Practice, Application, Performance, and Quality Control of Plant Applied, Fusion Bonded Epoxy External Pipe Coating.
NACPA 12-78 – National Association of Pipe Coating Applicators External Application Procedure for Plant Applied fusion Bonded Epoxy (FBE) to Steel Pipe.
SAES-H-002 Internal and External Coatings for Steel Pipelines and Piping
09-SAMSS-089 Shop-Applied External FBE Coating
09-SAMSS-091 Shop-Applied Internal FBE Coatings

2.1.2 Polyethylene Coating

CAN/CSA Z245.21 External Polyethylene Coating for Pipe
DIN 30670 Polyethylene Sheathing of Steel Tubes and of Steel Shaped Fittings
NFA 49-710 External Three-Layer Polyethylene Based Coating, Application by Extrusion
DNV-RP-F106 Factory Applied External Pipeline Coatings For Corrosion Control
AS/NZS 1518 External Extruded High-Density Polyethylene Coating System for Pipes
ISO 21809-1 Petroleum and natural gas industries — External coatings for buried or submerged pipelines used in pipeline transportation systems – Part 1: Polyolefin coatings (3- layer PE and 3- layer PP)
ISO 21809-4:2009, Petroleum and natural gas industries -External coatings for buried or submerged pipelines used in pipeline transportation systems-Part 4: Polyethylene Coatings (2-layer PE)
DEP 31.40.30.31-Gen. TECHNICAL SPECIFICATION FOR EXTERNAL POLYETHYLENE AND POLYPROPYLENE COATING FOR LINE PIPE
IPS-G-TP-335 Material and Construction Standard for Three Layer Polyethylene Coating System
NFA 49-710 External 3 layer Polyethylene Coating
PETROBRAS’ ET-200.03 Engineering Specification (“Piping Materials for Production and Process Facilities”) for using low density linear polyethylene in carbon steel piping, as to appendix 13 of such specification.
09-SAMSS-113 External Renovation Coating for Buried Pipelines and Piping (APCS-113)
UNI 9099-DIN 30670 Polyethylene Coating Applied by Extrusion

2.1.3 Polypropylene Coating

DIN30678 Polypropylene Sheathing of Steel Tubes and of Steel Shaped Fittings
EN 10286 Steel tubes and fittings for onshore and offshore pipelines –External three layer extruded polypropylene based coatings.
NFA 49-711 External Three-Layer Polypropylene Based Coating, Application by Extrusion
09-SAMSS-114 Shop-Applied Extruded, Three-Layer Polypropylene External Coatings for Line Pipe

2.1.4 Polyurethane Coating

AWWA C222-99: Polyurethane Coatings for the Interior and Exterior of Steel Water Pipe and Fittings
BS 5493- Polyurethane Coating
DIN 30677.2 polyurethane Insulation of the fittings
EN 10290- External Liquid Applied Polyurethane Coatings

2.1.5 Polyolefin Coating

AWWA C225-03: Fused Polyolefin Coating Systems for the Exterior of Steel Water Pipelines
AWWA C215-99: Extruded Polyolefin Coatings for the Exterior of Steel Water Pipelines
AWWA C216-00 Standard for Heat-Shrinkable Cross-Linked Polyolefin Coatings for the Exterior of Special Sections, Connections, and Fitting for the Steel Water Pipelines
AWWA C224 – 01: Two-layer Nylon-11 Based Polyamide Coating System for Interior and Exterior of Steel Water Pipe and Fittings
AWWA C225 – 03: Fused Polyolefin Coating Systems for the Exterior of Steel Water Pipelines

2.1.6 Tape Coating

ISO 21809-3:2008, Petroleum and natural gas industries-External coatings for buried or submerged pipelines used in pipeline transportation systems-Part 3: Field joint coatings
AWWA C209-00: Standard for Cold-Applied Tape Coatings for the Exterior of Special Sections, Connections, and Fittings for Steel Water Pipelines
AWWA C214-00 Standard for Tape Coating Systems for the Exterior of the Steel Water Pipelines
AWWA C217-99 Standard for Cold-Applied Petrolatum Tape and Petroleum Wax Tape Coatings for the Exterior for Special Sections, Connections, and Fittings for Buried/Submerged Steel Water Pipelines
AWWA C218-02 Standard for Coating the Exterior of Aboveground Steel Water Pipelines and Fittings
AWWA C224-01: Two-layer Nylon-11 Based Polyamide Coating System for Interior and Exterior of Steel Water Pipe and Fittings
EN 12068 – DIN 30672 STANDARD-POLYETHYLENE SELF ADHESIVE TAPES

2.1.7 Bitumen Coating

DIN 30673 Bitumen coatings and linings for steel pipes, fittings and vessels.
BS 534

2.1.8 Coal-Tar Enamel Coating

AWWA C-203 Coal-Tar Protective Coatings and Linings for Steel Water Pipelines-Enamel and Tape-Hot-Applied
AWWA C205 Cement Mortar Protective Lining and Coating for Steel Water Pipe – 4 inch (100 mm) and Larger- Shop Applied
BS 534

2.1.9 Concrete Weighted Coating

DNV-OS-F101 Submarine Pipeline System
ASTM C171 Specification for Sheet Material for Coating Concrete
BS EN 12620 Aggregates for Concrete
ISO 21809-5:2009, Petroleum and natural gas industries -External coatings for buried or submerged pipelines used in pipeline transportation systems – Part

5:External concrete coating.

ASTM C42 Standard Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete
ASTM C642 Standard Test Method for Specific Gravity, Absorption and Voids in Hardened Concrete
ASTM C87 Standard Test Method for Effect of Impurities in Fine Aggregate on Strength of Mortar BS 1881 Methods of Testing Concrete
BS 3148 Methods of Test for Water for Making Concrete
BS 4482 Hard Drawn Mild Steel Wire for the Reinforcement of Concrete
BS 4483 Specification for Steel Fabric for the Reinforcement of Concrete
BS 4449 Specification for Carbon Steel Bars for Reinforcement of Concrete
ISO 4012 Determination of Compressive Strength of Test Specimen

2.1.10 Marine Coating

EN ISO 12944:1998 – Paints & Varnishes – Corrosion Protection of Steel Structures by protective paint system (parts 1 – 8)
ISO 20340:2009 Paints and varnishes – Performance requirements for protective paint systems for offshore and related structures
ISO 15741 Paints and varnishes-Friction-reduction coatings for the interior of on- and offshore pipelines for non-corrosive gases

2.1.11 Other specification

British Gas BGC/PS/CM1,
BGC/PWS/CM2
GAZ de France R 09
NACE RP 0181
NF A 49-706
TS 5140
TS 5139

2.2. Lining

2.2.1 Epoxy Lining

AWWA C210: Liquid-Epoxy Coating Systems for the Interior and Exterior of Steel Water Pipelines
API RP512 or NFA 49-709 Internal can be epoxy 80 microns
TS EN 10289
NFA 49708 Recommended Practice for Internal Coating of Line Pipe

2.2.2 Bitumen Lining

DIN 30673 Bitumen coatings and linings for steel pipes, fittings and vessels
UNI-ISO 5256/87 STANDARD-BITUMEN COATING
BS 534

2.2.3 Cement Mortar Lining

AS/NZS 1516 Cement Mortar Lining of Pipelines In Situ
AWWA C203-02: Coal-Tar Protective Coatings & Linings for Steel Water Pipelines, Enamel & Tape, Hot-pap. (Incl. add. C203a-99)
AWWA C205-00: Cement-Mortar Protective Lining and Coating for Steel Water Pipe- 4 In. (100 mm) and Larger-Shop application
AWWA C602 Standard for Cement-Mortar Lining of Water Pipelines – 4 inch (100 mm) and Larger – In Place
BS 534

2.2.4 Shop Cement Lined Piping

AWWA C205,C104,C602
DIN 2614
British Standard BS 534
British Petroleum GS 106-1
Shell DEP 30.48.30.31-Gen.
Saudi Aramco 01-SAMSS-005
KNPC ENG STD 87C1
API RP 10E

Pipe Coating Products

Fusion Bonded Epoxy – Fusion Bond Epoxy is a powder epoxy thermosetting coating applied for anticorrosion protection to steel pipelines. The pipe is first blast cleaned and heated. Then epoxy powder is spray applied by electrostatic guns to melt and form a uniform layer that hardens within a minute from application. Utilizing industry accepted materials supplied by manufacturers such as 3M, DuPont, and Valspar, the facility can apply FBE in a wide range of thickness to cost effectively meet any project specifications.
Fusion Bonded Epoxy with Abrasion Resistance Overcoating (FBE/ARO) – Utilizing two completely separate powder systems, the facility can produce FBE with an ARO at unprecedented processing speeds using industry accepted materials such as 3M 6352, DuPont 7-2610, and Lilly 2040.
Fusion Bonded Epoxy with High Temperature Resistant Overcoating – Utilizing two completely separate powder systems, the facility can produce FBE with a high operating temperature resistant overcoating such as DuPont’s Nap-Gard Gold and 3M’s 6258.
Fusion Bonded Epoxy with Zap-Wrap Overcoating – The facility is capable of processing line pipe with connections and of applying the Zap-Wrap abrasion resistance overcoating to the ends of each pipe.

Three Layer Polyethylene (3LPE)

To improve anticorrosion performance and adhesion, an additional layer of epoxy primer is sprayed onto pipe surfaces prior to the adhesive layer and Polyethylene top layer application. Three Layer Polyethylene is suitable for service temperatures from 60°C to 80°C (85°C peaks). Typical coating thickness is from 1-2 mm to 3-5 mm.

Three Layer Polypropylene (3LPP)

If a wider service temperature range and high stiffness is required, adhesive and top layers, applied over primer layer, are based on polypropylene instead of polyethylene. Three Layer Polypropylene is suitable for service temperatures up to 135 °C (140°C peaks). Typical coating thickness is from 1-2 mm to 3-5 mm.

Three Layer Polypropylene and Polyethylene

Three Layer applications involve a thermoplastic coating applied to steel pipelines as a form of anticorrosion protection. This mechanical resistance is appropriate when the risk of particularly severe coating damages exist. The Three Layer process involved several steps. First, the pipe surface is blast cleaned to remove any external residue from the mill or storage. It is then heated and sprayed with a Fusion Bond Epoxy (FBE) primer followed by the application of an adhesive copolymer and polyolefin polymers that are wrap extruded, one over the other.

Field applied products

3M: SK 134, SK6233, SK6352 Toughkote, SK 314, SK 323, SK 206N, SK 226N, SK 6251 DualKote SK-6171, SK 206P, SK226P,
3M Internal Coatings: Coupon EP2306HP
DuPont: 7-2500, 7-2501, 7-2502, 7-2508, 7-2514, 7-2803, 7-2504 Nap Gard Gold 7-2504, Nap Rock: 7-2610, 7-2617 FBE Powders
DuPont: Repair Kits; 7-1631, 7-1677, 7-1862, 7-1851
DuPont Internal Coatings: 7-0008, 7-0010, 7-0014, 7-0009SGR, 7-0009LGR, 7-2530, 7-2534, 7-2509
Akzo Nobel: FBE – Fusion Bond Epoxy
Internline 876 Seal Coat
Hampel: 85448,97840
Denso: 7200, 7900 High Service Temperature Coatings
Internal Liquid Epoxy: Powercrete Superflow

Delivery

FAQs

Advantage of ERW pipe

The alloy content of the coil is often lower than similar grades of steel plate, improving the weldability of the spiral welded pipe. Due to the rolling direction of spiral welded pipe coil is not perpendicular to the pipe axis direction, the crack resistance of the spiral welded pipe materials.

Inquiry

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FAQ

Q: How long is your delivery time?
A: The delivery time of customized products is generally 25 35 days, and non customized products are generally shipped within 24 hours after payment.

Q: Do you provide samples? Is it free?
A: If the value of the sample is low, we will provide it for free, but the freight needs to be paid by the customer. But for some high value samples, we need to charge a fee.

Q: What are your payment terms?
A: T/T 30% as the deposit,The balance payment is paid in full before shipment

Q: What is the packaging and transportation form?
A: Non steaming wooden box and iron frame packaging. Special packaging is available according to customer needs. The transportation is mainly by sea.

Q: What is your minimum order quantity?
A: There is no minimum order quantity requirement. Customized products are tailor made according to the drawings provided by the customer.