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ASTM A790 DSS Welded Pipes 12 Inch SCH10S 6 MTR

Size:12 Inch (323.9mm)
Wall thickness: SCH10S (4.57mm)
Material: F51 (UNS S31803/UNS S32205)
Length: 6M


Type: DSS Welded Pipes
Material: F51 (UNS S31803/UNS S32205)
Size: 12 Inch (323.9mm) * SCH10S (4.57mm)

Standard: ASTM A790

Length: Normally fixed length 6m, can as per customer’s requirement.

End: Beveled End,Plain End

DSS (Duplex stainless steel)

What is DSS welded pipe?

DSS welded pipe is made of steel or steel strip that is welded after being curled and formed by a set and mold. DSS welded pipe production process is simple, has high production efficiency, a variety of specifications, less equipment investment, and generally lower strength than seamless steel pipe.
Since the 1930s, with the rapid development of high-quality strip steel continuous rolling production and the progress of welding and inspection technology, the quality of the welded seam continues to improve, the increasing variety of welded steel pipe specifications and in more and more areas, especially in the heat transfer equipment with tubes, decorative tubes, low-pressure fluid tubes instead of seamless steel tubes. One small-diameter stainless steel welded pipe is continuous online production; the thicker the wall thickness, the larger the investment in the unit and dissolving equipment, and the less economical and practical it is. The thinner the wall thickness, the input-output ratio will drop accordingly; secondly, the process of the product determines its advantages and disadvantages, general welded steel pipe with high precision, uniform wall thickness, high brightness of the tube appearance (the surface grade of the steel plate determines the surface brightness of the steel pipe), and can be arbitrarily sized. Therefore, it reflects its economy and beauty in high-precision, low and medium-pressure fluid applications.

Duplex stainless steel welded pipe has good welding properties compared with ferritic stainless steel and austenitic stainless steel; it is neither like the welded heat-affected zone of ferritic stainless steel due to severe coarsening of the grain and a significant reduction in plastic toughness nor like austenitic stainless steel, which is more sensitive to welding heat cracking.
Due to its special advantages, duplex stainless steel is widely used in petrochemical equipment, seawater and wastewater treatment equipment, oil and gas pipelines, paper-making machinery, and other industrial fields. In recent years, it has also been studied for bridge load-bearing structure fields, with good prospects for development.
Duplex stainless steel is in its solid hardening organization in the ferrite and austenite phases, each half, with the general minimum phase content of perhaps 30%.

Chemical Composition of UNS S31803 Welded Pipe and UNS S32205 Welded Pipe

EL. UNS S31803 UNS S32205
C ≤0.030 ≤0.030
Mn ≤2.00 ≤2.00
P ≤0.030 ≤0.030
S ≤0.020 ≤0.020
Si ≤1.00 ≤1.00
Ni 4.5-6.5 4.5-6.5
Cr 21.0-23.0 22.0-23.0
Mo 2.5-3.5 3.0-3.5
N 0.08-0.20 0.14-0.20

Mechanical Properties of UNS S31803 Welded Pipe and UNS S32205 Welded Pipe

Test S31803 S32205
Su 620 655
[80] [95]
Sy 450 485
[65] [70]
El. 25 25
HBW 290 290
HRC 30 30
HV 390 290

  • *Tensile and hardness requirements for ASTM A789 & ASTM A790 Grade S31803, S32205, S32750 and S32760.
  • *Su: tensile strength, min. MPa [ksi]; *Sy: yield strength, min. MPa [ksi]; El.: elongation in 2″, min. %.
  • *Hardness, maximum: Brinell (HBW), Rockwell (HRC), Vickers (HV).

What are the characteristics of DSS?

  • Seawater Handling Equipment
  • Pulp Mill Bleach Systems
  • Tall Oil Distillation Columns and Equipment
  • Chemical Processing Equipment
  • Food Processing Equipment
  • Desalination Equipment
  • Flue Gas Desulfurization Scrubbers
  • Oil and Gas Production Equipment

Production chart of LSAW steel pipe

LSAW steel pipe can be divided into high frequency LSAW steel pipe and submerged arc welded LSAW steel pipe according to the production process. According to different forming methods, submerged arc welded longitudinal steel pipe can be divided into UOE, RBE and JCOE. the following is the most common forming process of longitudinal steel pipe.

20230510081742 33498 - ASTM A790 DSS Welded Pipes 12 Inch SCH10S 6 MTR
1. Plate detection: After entering the production line, the steel plate used for large diameter submerged arc longitudinal steel pipe is first subjected to full-plate ultrasonic flaw detection.
2. Milling: Milling on both sides of the steel plate with an edge milling machine to meet the requirements of plate width, plate edge parallelism and bevel shape.
3. Pre-bending: the plate edge is pre-bent by the pre-bending machine to make the plate edge with the required curvature .
4. Forming: on the JCO forming machine, half of the pre-bent steel plate is first pressed into a J-shape, then the other half of the plate is bent into a C-shape, and finally an O-shaped opening is formed.

Production chart of LSAW steel pipes - ASTM A790 DSS Welded Pipes 12 Inch SCH10S 6 MTR

5. Pre-welding: straight seam welded steel pipe is continuously welded by gas shielded welding (MAG).
6. Internal welding: longitudinal seam steel pipe using longitudinal multi-wire submerged arc welding (up to 4).
7. External welding: longitudinal multi-wire submerged arc welding is used on the outside of the longitudinal submerged arc welded pipe.
8. Ultrasonic testing I: 100% detection of the internal and external welds and base material of the straight seam welded pipe weld.
   X-ray flaw detection I: 100% X-ray industrial television inspection of the internal and external welds, using image processing systems to ensure the sensitivity of flaw detection.
10. Expansion: full-length expansion of buried straight seam steel pipe to improve the dimensional accuracy of the pipe and improve the stress distribution within the pipe.
11. Hydraulic test: check the expanded steel pipe one by one on the hydraulic test machine to ensure that the steel pipe meets the test pressure required by the standard. This machine has automatic recording and storage function.
12. Chamfering: pipe end processing qualified steel pipe, to meet the requirements of the bevel size of the pipe end.
13. Ultrasonic testing II: straight seam welded steel pipe expansion after the hydraulic test, should be re-examined ultrasonic testing to check its possible defects.
      X-ray flaw detection 2: steel pipe expansion, water pressure test after the X-ray industrial television inspection and tube end welding negatives taken.
15. Pipe end magnetic particle detection: detection of magnetic particle at the end of the pipe to detect defects at the end of the pipe.
16. Anticorrosion and coating: qualified steel pipe shall be treated with anticorrosion and coating according to user requirements.

DSS welded pipes made to ASTM A790 shall be furnished with the solution annealing treatment followed by a water quench. The solution annealing temperature ranges for S31803, S32205, S32750, and S32760 are 1870-2010°F [1020-1100°C], 1870-2010°F [1020-1100°C], 1880-2060°F [1025-1125°C], 1960-2085°F [1070-1140°F], respectively.

China DSS Welded Pipe Manufacturer offers ASTM A790 DSS Welded Pipes 12 Inch SCH10S 6 MTR.

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