Manufacturing, Characteristics, and Applications of 022Cr25Ni7Mo4N Duplex Stainless Steel Seamless Pipe

1. 022Cr25Ni7Mo4N duplex stainless steel seamless pipe products must comply with the requirements of TSG D7002, Rules for Type Testing of Pressure Piping Components
2. Chemical Composition of 022Cr25Ni7Mo4N Duplex Stainless Steel Seamless Pipe: Carbon: ≤0.030, Silicon: ≤0.80, Manganese: ≤1.20, Phosphorus: ≤0.035, Sulfur: ≤0.015, Nickel: 6.00-8.00, Chromium: 24.0-26.0, Molybdenum: 3.00-5.0, Nitrogen: 0.21-0.32, Copper: ≤0.50
Common specifications for 22Cr25Ni7Mo4N duplex stainless steel seamless pipe: OD 57mm-2680mm, Thickness 1.2mm-60mm.
Delivery status of 22Cr25Ni7Mo4N duplex stainless steel seamless pipe: Heat treatment + pickling.

First, the manufacturing process of 22Cr25Ni7Mo4N duplex stainless steel seamless pipe.
The manufacturing process of 22Cr25Ni7Mo4N duplex stainless steel seamless pipe primarily includes smelting, casting or forging, hot or cold rolling, and subsequent heat treatment and surface treatment. During the smelting stage, raw materials are melted using either the electric furnace or electroslag method to ensure that the metal composition meets standards. The electric furnace method melts the metal in an electrically heated furnace, while the electroslag method utilizes electroslag smelting technology to separate the slag and liquid during the smelting process. Both methods effectively produce plates and round bars that meet the requirements for 022Cr25Ni7Mo4N duplex stainless steel seamless pipe. Casting or forging processes can yield various forms of material, such as plates, round bars, and forgings. Forging further enhances the material's strength and toughness while maintaining its excellent corrosion and wear resistance. Hot rolling and cold rolling are the primary methods for producing seamless steel pipe. Hot rolling forms the metal billet at high temperatures and is suitable for producing thick, simple-shaped parts. Cold rolling, on the other hand, applies pressure to the metal billet at room temperature, gradually thinning and deforming it through a series of rollers to produce thinner, smooth-surfaced plates and strips.

Second, the material properties of 022Cr25Ni7Mo4N duplex stainless steel seamless pipe.
022Cr25Ni7Mo4N duplex stainless steel seamless pipe is highly valued for its excellent mechanical properties, corrosion resistance, and wear resistance. This material is a ferrite-austenite duplex stainless steel, combining the beneficial properties of both ferritic and austenitic steels. Its high chromium and molybdenum content provides excellent resistance to pitting, crevice, and uniform corrosion, while its duplex microstructure ensures high resistance to stress corrosion cracking. Furthermore, 022Cr25Ni7Mo4N duplex stainless steel seamless pipe boasts high yield strength and tensile strength, making it a viable alternative to traditional stainless steels such as 316L in many applications. Its excellent toughness, weldability, and formability significantly broaden its application range. During welding, 022Cr25Ni7Mo4N duplex stainless steel seamless pipe exhibits excellent weldability, making it suitable for joining using various welding methods and resistant to defects such as cracking.

Third, Applications of 022Cr25Ni7Mo4N Duplex Stainless Steel Seamless Pipe
- Oil and Gas Industry: 022Cr25Ni7Mo4N duplex stainless steel seamless pipe is used in the manufacture of pipelines, vessels, valves, and other equipment handling corrosive media. Its high corrosion resistance and high strength enable it to operate stably in harsh environments, extending the service life of the equipment.
- Shipbuilding: This material is used in the manufacture of ship structures, seawater treatment equipment, and offshore platforms. In marine environments, 022Cr25Ni7Mo4N duplex stainless steel seamless pipe resists seawater corrosion, ensuring the safety and stability of ship structures.
- Food Processing Industry: 022Cr25Ni7Mo4N duplex stainless steel seamless pipe is used in the manufacture of food contact equipment and components. Its non-toxic, harmless, and easy-to-clean properties make it an ideal choice for food processing equipment.
- Seawater Desalination and Treatment Facilities: The corrosion resistance of 022Cr25Ni7Mo4N duplex stainless steel seamless pipe makes it the preferred material for corrosion-resistant equipment and components. In the pulp and paper industry, it also exhibits excellent corrosion and wear resistance, making it suitable for manufacturing-related equipment.

Fourth, the environmental adaptability of 022Cr25Ni7Mo4N duplex stainless steel seamless pipes
022Cr25Ni7Mo4N duplex stainless steel seamless pipes perform excellently in a variety of environments. In corrosive environments such as those with strong acids and alkalis, corrosion can be addressed through regular surface treatment or replacement with more corrosion-resistant materials. In environments with severe contact wear, increasing surface roughness or replacing with more wear-resistant materials can effectively address wear. Furthermore, the heat treatment process of 022Cr25Ni7Mo4N duplex stainless steel seamless pipes is a key step in ensuring their excellent performance. During heat treatment, temperature and time must be strictly controlled to ensure optimal corrosion resistance and mechanical properties. Research has shown that the sensitive temperature range for σ phase precipitation is 850-900°C, with a complete dissolution temperature of 1010°C. Therefore, during hot working, repeated heating or prolonged holding within the σ phase precipitation temperature range should be avoided to prevent defects such as cracks.

Fifth, the economic benefits of 022Cr25Ni7Mo4N duplex stainless steel seamless pipes. 
Although the initial purchase cost of 022Cr25Ni7Mo4N duplex stainless steel seamless pipes may be higher than that of ordinary stainless steel, their superior performance and long service life make them less expensive in the long run. Considering factors such as the performance-to-cost ratio, expected service life, maintenance costs, safety, and reliability, using 022Cr25Ni7Mo4N duplex stainless steel seamless pipes can significantly reduce overall costs and improve economic benefits.