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About us
Tianjin lefin Industrial
TIANJIN LEFIN STEEL GROUP containing Tianjin lefin Industrial Co.,Ltd. 、Tianjin lefin steel import & export Co.,Ltd and Tianjin Shengqifeng International Trading Co., Ltd. -
Products
Steel Pipe Processing
Our main products include 1/2inch to 16 inch ERW PIPE/GI PIPE which has been produced according to BS1387/ASTM A53/EN10219/EN10255/EN10217 Standard -
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Service Capability
Guarantee Quality
Our steel pipes are suitable for oil, natural gas, shipbuilding, chemical industry, water conservancy, electrical, steel structure, construction and other related fields.
- Details
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DSAW LINE PIPE (Double Submerged Arc Welded Line Pipe) is a kind of welded steel pipe made of double submerged arc welding process, which is widely used in long-distance pipeline systems such as oil and natural gas.
Products Description
1. Material preparation
• The use of high-strength steel plates (such as API 5L X42 to X80 grades) as raw materials, subject to strict chemical composition and mechanical properties standards.2. Forming and welding
• Pre-bending and forming:After pre-bending, the steel plate is gradually bent into a cylindrical shape by the forming machine (JCOE/UOE process).
• Internal and external welding:
◦ The inner and outer walls of the steel pipe are submerged arc technology, and the arc is covered by flux during welding to prevent oxidation and ensure penetration and uniformity.
◦ The inner welding is done on the inside of the tube and the outer welding is done on the outside, creating a high quality weld on both sides (more reliable than single side welding).3. Post-processing
• Expanding: Hydraulic or mechanical expanding processes eliminate residual stress and ensure roundness and dimensional accuracy.
• Non-destructive testing (NDT) : Using ultrasonic (UT), radiographic (RT) or magnetic particle testing (MT) to check for weld defects.
• Coating and anti-corrosion: Coating epoxy resin (FBE), three layers of polyethylene (3PE) and other anti-corrosion layers according to requirements.Key characteristics
1. High strength and toughness
• Suitable for high pressure conveying (can withstand more than 10MPa pressure), material grade up to X80 (yield strength above 550MPa).2. Large caliber and thick wall
• Typical specifications: Outer diameter 406-1600mm, wall thickness 6-40mm, length 6-18m.
• Suitable for laying the main line of long distance oil/gas pipelines.3. High welding quality
• Double-sided submerged arc welding has large penetration depth, few defects, and weld strength is close to the base material.4. Strong environmental adaptability
• Suitable for low temperature, high pressure, high corrosion (such as submarine pipeline) and other harsh conditions.Application fields
• Oil and gas transportation: land and subsea long-distance pipelines (such as west-east gas transmission, cross-border pipelines).
• Chemicals and energy: Transportation of liquefied natural gas (LNG), carbon dioxide, hydrogen, etc.
• Infrastructure: water conservancy projects, nuclear power cooling systems and other high-pressure and durable scenarios.Standards and Certification
• International standards: API 5L (American Petroleum Institute), ISO 3183, DNV (Norske Veritas), etc.
• Environmental requirements: HIC (resistance to hydrogen cracking) and SSC (sulfide stress corrosion) tests are required.Advantages and limitations
Advantages:
• Stable weld quality, suitable for high pressure, large flow conveying;
• Preferred solution for large diameter pipes with long service life (up to more than 50 years).
Disadvantages:
• Long production cycle and high cost;
• Small diameter pipelines are less economical than ERW.
DSAW LINE PIPE
Subcategory
Keyword
- Details
-
DSAW LINE PIPE (Double Submerged Arc Welded Line Pipe) is a kind of welded steel pipe made of double submerged arc welding process, which is widely used in long-distance pipeline systems such as oil and natural gas.
Products Description
1. Material preparation
• The use of high-strength steel plates (such as API 5L X42 to X80 grades) as raw materials, subject to strict chemical composition and mechanical properties standards.2. Forming and welding
• Pre-bending and forming:After pre-bending, the steel plate is gradually bent into a cylindrical shape by the forming machine (JCOE/UOE process).
• Internal and external welding:
◦ The inner and outer walls of the steel pipe are submerged arc technology, and the arc is covered by flux during welding to prevent oxidation and ensure penetration and uniformity.
◦ The inner welding is done on the inside of the tube and the outer welding is done on the outside, creating a high quality weld on both sides (more reliable than single side welding).3. Post-processing
• Expanding: Hydraulic or mechanical expanding processes eliminate residual stress and ensure roundness and dimensional accuracy.
• Non-destructive testing (NDT) : Using ultrasonic (UT), radiographic (RT) or magnetic particle testing (MT) to check for weld defects.
• Coating and anti-corrosion: Coating epoxy resin (FBE), three layers of polyethylene (3PE) and other anti-corrosion layers according to requirements.Key characteristics
1. High strength and toughness
• Suitable for high pressure conveying (can withstand more than 10MPa pressure), material grade up to X80 (yield strength above 550MPa).2. Large caliber and thick wall
• Typical specifications: Outer diameter 406-1600mm, wall thickness 6-40mm, length 6-18m.
• Suitable for laying the main line of long distance oil/gas pipelines.3. High welding quality
• Double-sided submerged arc welding has large penetration depth, few defects, and weld strength is close to the base material.4. Strong environmental adaptability
• Suitable for low temperature, high pressure, high corrosion (such as submarine pipeline) and other harsh conditions.Application fields
• Oil and gas transportation: land and subsea long-distance pipelines (such as west-east gas transmission, cross-border pipelines).
• Chemicals and energy: Transportation of liquefied natural gas (LNG), carbon dioxide, hydrogen, etc.
• Infrastructure: water conservancy projects, nuclear power cooling systems and other high-pressure and durable scenarios.Standards and Certification
• International standards: API 5L (American Petroleum Institute), ISO 3183, DNV (Norske Veritas), etc.
• Environmental requirements: HIC (resistance to hydrogen cracking) and SSC (sulfide stress corrosion) tests are required.Advantages and limitations
Advantages:
• Stable weld quality, suitable for high pressure, large flow conveying;
• Preferred solution for large diameter pipes with long service life (up to more than 50 years).
Disadvantages:
• Long production cycle and high cost;
• Small diameter pipelines are less economical than ERW.
Related products
Product Consulting
Address: Hengtai Road,Daqiuzhuang Town,Jinghai County,Tianjin,China
Mob: +8615122229899(whatspp)
Phone: +86 22 58171905
Fax: +86 22 58171902
E-mail:info@lefinsteel.com
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