Duplex Stainless Steel Pipe
Duplex Stainless Steel Pipe Manufacturer
We provide a comprehensive selection of duplex stainless steel pipes and pipe fittings. The standard governs the manufacturing process of duplex pipes, ensuring that they meet strict quality standards. These pipes are available in various sizes, shapes, and lengths, making them suitable for a wide range of applicationsThey can be threaded or welded together with valves to create complex piping systems that can handle even the most demanding industrial processes.
Why Choose Us
Product application fields
Industrial stainless steel pipes & tubes have very high quality and price advantages which meet the ASTM, ASME, ANSI standard.Fields cover pipe fittings, flanges, steel plates, round bars, and customized pipe spools etc., we can provide materials such as stainless steel, duplex steel, nickel alloy and some carbon steel.
Productio Equipment
HT PIPE have fully automatic production line equipment, 130 type unit production line(The maximum outer diameter is 426mm), Automatic welding, On-line solution annealing, Cantilever welding machine, Bending forming machine, Integer machine, Inner welding machine, Large caliber pipe welding, Heat treatment, Pickling ect. We can provide customers with some steel pipe fitting flange assemblies.
Production Market
We mainly deal in raw materials for oil and gas pipelines. Our main markets are Southeast Asia, Asia, the Middle East, Europe, some countries in North America and South America. Including Brazil, South Africa, Indonesia, India, Singapore, Malaysia, Iran, Russia, UAE, Chile, Laos, etc. We have been cooperating with some customers for more than 10 years. In the future, we will stick to our original intention and cooperate with more customers.
Our Service
We always maintain an efficient customer communication plan, from order communication to production scheduling, production, product testing, delivery, etc., we are committed to providing high-quality products to our friends and customers. However, it is inevitable that not everything is perfect, when there is a problem with our products, we will maintain a highly responsible attitude and propose reasonable solutions for our customers, please believe us, we are always doing better work hard on the way.
Benefits of Duplex Stainless Steel Pipe
Corrosion Resistance
Duplex SS contains about 20% of chromium in addition to the molybdenum content. Together, these elements make duplex stainless steel grades extremely resistant to severely corrosive environments. Duplex and Super duplex grades of stainless steel can withstand crevice, pitting, chloride ion, and stress corrosion even at elevated temperatures.
Machining Properties
Duplex Stainless Steel grades have great fatigue strength and superior mechanical properties.
Heat resistant and hot-working range
Duplex stainless steel grades are resistant to heat and high-temperature environments. Duplex Steel Pipes and Tubes do not necessarily require forging, they can be rolled directly. However, in high heat environments, it is tougher to work with chromium alloys than austenitic alloys. Thus, it is easier to hot-roll duplex SS pipes that have low chromium content.
Weldability
Duplex SS grades have superior weldability. These pipes do not crack easily under pressure and heat influence. Preheating the material before the welding process is not required in the case of Duplex SS Pipes.
Types of Duplex Stainless Steel Pipe
Duplex stainless steel pipes are available in several types, each designed to meet specific performance requirements in various applications. The main types of duplex stainless steel pipes are categorized based on their alloying content and corrosion resistance properties.
Lean duplex
Lean duplex stainless steel pipes are characterized by their lower content of alloying elements, particularly nickel and molybdenum. This makes them a more economical option while still offering improved properties compared to standard austenitic grades.
Standard duplex
Standard duplex stainless steel pipes are the most commonly used type in the duplex family. They offer an excellent balance of strength, corrosion resistance, and cost-effectiveness, making them suitable for a wide range of applications.
Super duplex
Super duplex stainless steel pipes have higher contents of chromium, molybdenum, and nitrogen compared to standard duplex. This results in superior corrosion resistance, particularly in chloride-containing environments
Hyper duplex
Hyper duplex stainless steel pipes represent the most highly alloyed type in the duplex family. They are designed for extremely aggressive environments where even super duplex might not be sufficient.
ASTM A790 UNS S31803 Pipe Specifications
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Specifications |
ASTM A 789 / ASME SA 789 ASTM A 790 / ASME SA 790 |
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Types |
Seamless / Welded / EFW / Fabricated |
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Pipe Range |
1 / 2" NB - 8" NB |
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Outer Diameter |
6.0 - 630mm |
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Wall Thickness |
0.3mm – 50 mm |
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Schedules |
SCH5, SCH20, SCH30, SCH40, STD, SCH60, SCH80, XS, SCH120, SCH140, SCH160, XXS |
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Length |
Single Random, Double Random & Required Length |
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Form |
Round Pipes, Square Pipes, Rectangular Pipe, "U" Shape, Hydraulic Pipes |
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End |
Plain End, Beveled End, Treaded |
How To Weld Duplex Stainless Steel Pipe?
Duplex steel welding mainly uses electrode arc welding, such as welding rods and welding wires. The welding methods of different grades of duplex steel and other alloy steels should be determined according to the chemical composition of the electrode used, the joint location and the welding conditions.
In order to ensure a high carbon content in the weld, the base metal must be preheated and post-heated to reduce the carbon content in the weld. The electrode must be dried at 350°C for 1 hour before welding, and at 600°C after welding. Temper at ~700°C for 1 hour and then weld.
When welding, a small current should be used to ensure that the content of austenite and/or ferrite in the weld metal reaches close to 1:1. If a larger current is used, the ferrite content in the weld metal will increase, causing changes in the structure of the welding heat-affected zone and reducing the corrosion resistance of the joint.
During the welding process of duplex stainless steel, the phase transformation of austenite and ferrite will generate stress, causing changes in the internal structure of the welded joint, such as intergranular corrosion, recrystallization stress corrosion, and heat-affected zone embrittlement. Therefore, during the welding process, it is necessary to ensure that the weld metal has sufficient plasticity to prevent intergranular corrosion and embrittlement of the heat-affected zone. For this reason, selecting appropriate welding materials is the key to ensuring the welding quality of duplex stainless steel.
The versatility of duplex stainless steel pipes and duplex stainless steel tubes lends them to a myriad of programs across various industries. From vital structural components in offshore systems to piping structures in chemical processing vegetation, their superior performance in corrosive environments makes them fundamental.
Duplex stainless pipes are extensively used in upstream, midstream, and downstream operations in the oil and gas zone. Their resistance to sulfide strain corrosion cracking and high electricity-to-weight ratio makes them ideal for subsea pipelines, umbilicals, and downhole tubing packages.
Moreover, inside the chemical and petrochemical industries, in which exposure to competitive chemical compounds is not unusual, duplex stainless steel pipes provide remarkable resistance to corrosion, thereby ensuring the integrity and durability of piping systems.
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