1. Definition
Alloy 31 is a nickel-chromium-iron-molybdenum-tungsten alloy developed by ThyssenKrupp in Germany in the 1980s. The alloy has excellent corrosion resistance and high temperature strength, and is suitable for manufacturing equipment in a variety of corrosive media.
2. Chemical composition
The chemical composition of Alloy 31 alloy is as follows:
Element | content (mass fraction, %)
—|—
Nickel | 30.0-35.0
Chrome | 26.0-28.0
Iron | 26.0-30.0
Molybdenum | 6.0-7.0
Copper | ≤1.0
Tungsten | ≤0.5
Aluminum | ≤0.2
Titanium | ≤0.2
Carbon | ≤0.015
Silicon | ≤0.5
Phosphorus | ≤0.02
Sulfur | ≤0.01
3. Production standard
The production standards of Alloy 31 alloy include the following standards:
1. ASTM B625: Inconel and Inconel-Molybdenum Alloy Plate, Sheet, and Strip.
2. ASTM B619: Inconel and Inconel-Molybdenum Welded Pipe.
3. ASTM B622: Inconel and Inconel-Molybdenum Seamless Tubes and Seamless Tube Processing Materials.
4. ASME SB-625: Inconel and Inconel Plate, Sheet, and Strip.
5. ASME SB-619: Inconel and Inconel-Molybdenum Welded Pipe.
6. ASME SB-622: Inconel and Inconel-Molybdenum Seamless Tubing and Seamless Tubing Materials.
7. UNS N08031: Used to manufacture manufacturing equipment in highly corrosive environments such as chemical industry, petrochemical industry, marine engineering, and sewage treatment.
4. Corrosion resistance
Alloy 31 has excellent corrosion resistance and performs well in a variety of highly corrosive environments. The alloy has good corrosion resistance to oxidizing media, reducing media and mixed media, including sulfuric acid, hydrochloric acid, nitric acid, chloride, ammonia water, sea water, etc. In addition, Alloy 31 alloy also has excellent resistance to stress corrosion cracking, especially suitable for corrosive environments under high temperature and high pressure.
5. High temperature resistance
Alloy 31 alloy has good high temperature resistance, and can maintain good mechanical properties and corrosion resistance at high temperatures. The alloy can be used at temperatures up to 1100°C and still has good strength, ductility and toughness at high temperatures. In addition, the alloy has excellent oxidation resistance and can perform well in high temperature oxidizing environments.
6. Typical application range
Alloy 31 alloy has excellent corrosion resistance and high temperature resistance, so it is suitable for a variety of industrial fields, including:
1. Chemical industry: used in the manufacture of chemical reactors, distillation towers, pipelines and pumps and other equipment.
2. Petrochemical industry: used in the manufacture of oil well casings, oil and gas pipelines, storage tanks and reactors and other equipment.
3. Marine engineering: used to manufacture seawater desalination equipment, seawater coolers, seawater pumps and equipment on offshore platforms.
4. Sewage treatment: used to manufacture sewage treatment equipment, including sewage treatment reactors, sewage treatment pumps, sewage treatment pipelines and sludge drying equipment, etc.
5. Others: Alloy 31 alloy is also suitable for the manufacture of food processing equipment, pharmaceutical equipment, power equipment and nuclear power equipment.
7. Hot working, cold working and heat treatment
1. Hot working: Alloy 31 alloy can be hot worked, including forging, hot rolling and hot extrusion. The thermal processing temperature range is 1000-1200°C, which can be adjusted as needed.
2. Cold working: Alloy 31 alloy can be cold worked, including cold rolling, cold drawing and cold bending. Due to the alloy’s excellent ductility and hardness, it can be cold worked to a greater extent.
3. Heat treatment: Alloy 31 alloy can be subjected to various heat treatments, including annealing and solution treatment. The solution treatment temperature is 1050-1150°C, and the holding time is 1-2 hours; the annealing treatment temperature is 950-1050°C, and the holding time is 1-2 hours. These heat treatments improve the alloy’s grain structure, increase hardness and strength, and reduce residual stress and the risk of stress corrosion cracking.
8. Machining and welding
1. Machining: Alloy 31 alloy can be processed in a variety of ways, including milling, turning, drilling and cutting. Due to the high hardness and toughness of this alloy, it is necessary to use high-quality cutting tools and machine equipment in the machining process to obtain good processing results.
2. Welding: Alloy 31 alloy can be used for various welding, including TIG welding, MIG welding and arc welding. In the welding process, it is necessary to use welding consumables that match Alloy 31 to ensure the corrosion and mechanical properties of the welded joint. Recommended welding materials include Alloy 31 welding wire and Alloy 31 solder, etc. During the welding process, attention needs to be paid to controlling the welding temperature and welding speed to avoid excessive residual stress and stress corrosion cracking.
9. Recommended welding materials
Recommended welding materials include Alloy 31 welding wire and Alloy 31 solder, etc.
10. Material specific gravity
Alloy 31 has a density of 8.1 g/cm³ and a specific gravity of 8.1.
11. Range of available products
The product range available for Alloy 31 alloy includes plate, sheet, strip, welded pipe, seamless pipe and seamless pipe processing material, etc. Its thickness, width and length can be customized according to customers’ requirements. In addition, Alloy 31 alloy can also be made into various shapes of parts and components, including pipes, flanges, elbows, tees, crosses, flanges and valves.
In conclusion, Alloy 31 alloy is an extremely corrosion-resistant and high-temperature-resistant alloy material suitable for many applications in highly corrosive environments.
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Post time: Aug-26-2023
