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E: enquiry@qilumetal.com
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431 stainless steel is a type of martensitic stainless steel, known for its high strength, good corrosion resistance, and excellent mechanical properties. Due to its combination of hardness, wear resistance, and moderate corrosion resistance, it is widely used in applications requiring durability and toughness. You can find equivalent grades in different steel standards, such as X17CrNi16-2/1.4057 from the European standard EN 10088-3, 17Cr16Ni2 from the Chinese standard GB/T 1220, SUS431 from the Japanese standard JIS G4303, and 20X17H2 from the Russian standard GOST 5632-76.
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AISI 431 is a top-tier martensitic stainless steel celebrated for its exceptional blend of strength, corrosion resistance, and machining adaptability. It complies with major global standards, including EN X17CrNi16-2 (1.4057), JIS SUS431, GB/T 1220 17Cr16Ni2, and GOST 20X17H2, making it a preferred material for cross-border industrial projects.
The alloy’s composition is carefully formulated with 15-17% chromium for corrosion resistance and 1.25-2.50% nickel for enhanced toughness. Its martensitic structure allows for significant strength improvement through heat treatment, distinguishing it from austenitic grades that lack such hardening capabilities. Available in hot-rolled bars, forged plates, and custom shapes, AISI 431 maintains consistent performance in both high-temperature and high-stress environments.
AISI 431 delivers impressive mechanical results. In the quenched and tempered (QT 900) condition, it reaches a tensile strength of 900-1050 Mpa and a minimum yield strength of 700 Mpa, with an elongation of 12% minimum—critical for heavy-load applications. For less demanding uses, QT 800 treatment provides a tensile strength of 800-950 Mpa and a yield strength of 600 Mpa minimum, balancing strength and flexibility.
Even at elevated temperatures, its stability remains outstanding. Under QT 800 conditions, the minimum 0.2% proof strength is 515 Mpa at 100℃ and 355 Mpa at 400℃, ensuring reliability in high-heat settings like industrial furnaces.
The alloy’s chemistry is optimized for performance:
· Carbon (C): 0.20% maximum to control hardness without compromising ductility
· Silicon (Si) and Manganese (Mn): 1.0% maximum each for improved casting properties
· Phosphorus (P): 0.040% maximum and Sulfur (S): 0.030% maximum to reduce brittleness
· Chromium (Cr): 15-17% and Nickel (Ni): 1.25-2.50% for a perfect balance of corrosion resistance and strength
This composition ensures compatibility with welding, forging, and precision machining processes.
AISI 431 is available in a wide range of forms to meet industrial needs:
· Hot rolled bars: Φ10mm-Φ130mm, with lengths of 5000-7000mm
· Hot forged bars: Φ140mm-Φ600mm, lengths of 2000-5800mm
· Plates/sheets: Thickness 2-250mm, width 310-1000mm
Surface finishes include turned, milled, ground (tolerance: +0/+0.05mm), and polished, with strict straightness (1mm/1000mm maximum) for precision components.
AISI 431’s unique properties make it indispensable across sectors:
· Automotive: Used in engine valves, turbocharger parts, and transmission shafts—its high strength resists wear under extreme engine pressures.
· Petrochemical: Ideal for valves, pump rotors, and pipe fittings, offering moderate resistance to industrial chemicals and hydrocarbons.
· Medical: Employed in surgical tools and temporary orthopedic implants, combining biocompatibility with the toughness to withstand sterilization.
· Energy: Selected for gas turbine components and nuclear fasteners, maintaining integrity at high temperatures and under mechanical stress.
· Marine: Used in propeller shafts and deck hardware, resisting saltwater corrosion better than standard carbon steels.
AISI 431 offers higher nickel content (1.25-2.50% vs. 420’s 0.5% maximum), resulting in better toughness and corrosion resistance. While 420 excels in hardness, AISI 431 provides a superior balance of strength and ductility, making it better for load-bearing parts.
Limited cold working is possible, but the alloy’s martensitic structure makes it more prone to work hardening. Annealing at 680-800℃ before cold forming helps maintain ductility.
Standard stock sizes (Φ10mm-Φ300mm bars) ship within 3 days. Custom forging or machining takes 2-4 weeks, depending on complexity.
Country | Standard | Grade |
USA | ASTM A276/276M | 431 |
EN | EN 10088-3 | X17CrNi16-2/1.4057 |
China | GB/T 1220 | 17Cr16Ni2 |
Japan | JIS G4303 | SUS431 |
Russia | GOST 5632-76 | 20X17H2 |
Grade | C | Si | Mn | P | S | Cr | Ni |
431 | 0.20 Max | 1.0 Max | 1.0 Max | 0.040 Max | 0.030 Max | 15-17 | 1.25-2.50 |
Grade | Tensile Strength | Yield Strength | Elongation | Hardness (HBW) |
17Cr16Ni2 | 900-1050 Mpa | 700 Mpa Min | 12% Min | 295 Max |
SUS431 | 780 Mpa Min | 590 Mpa Min |
AISI 431 is a top-tier martensitic stainless steel celebrated for its exceptional blend of strength, corrosion resistance, and machining adaptability. It complies with major global standards, including EN X17CrNi16-2 (1.4057), JIS SUS431, GB/T 1220 17Cr16Ni2, and GOST 20X17H2, making it a preferred material for cross-border industrial projects.
The alloy’s composition is carefully formulated with 15-17% chromium for corrosion resistance and 1.25-2.50% nickel for enhanced toughness. Its martensitic structure allows for significant strength improvement through heat treatment, distinguishing it from austenitic grades that lack such hardening capabilities. Available in hot-rolled bars, forged plates, and custom shapes, AISI 431 maintains consistent performance in both high-temperature and high-stress environments.
AISI 431 delivers impressive mechanical results. In the quenched and tempered (QT 900) condition, it reaches a tensile strength of 900-1050 Mpa and a minimum yield strength of 700 Mpa, with an elongation of 12% minimum—critical for heavy-load applications. For less demanding uses, QT 800 treatment provides a tensile strength of 800-950 Mpa and a yield strength of 600 Mpa minimum, balancing strength and flexibility.
Even at elevated temperatures, its stability remains outstanding. Under QT 800 conditions, the minimum 0.2% proof strength is 515 Mpa at 100℃ and 355 Mpa at 400℃, ensuring reliability in high-heat settings like industrial furnaces.
The alloy’s chemistry is optimized for performance:
· Carbon (C): 0.20% maximum to control hardness without compromising ductility
· Silicon (Si) and Manganese (Mn): 1.0% maximum each for improved casting properties
· Phosphorus (P): 0.040% maximum and Sulfur (S): 0.030% maximum to reduce brittleness
· Chromium (Cr): 15-17% and Nickel (Ni): 1.25-2.50% for a perfect balance of corrosion resistance and strength
This composition ensures compatibility with welding, forging, and precision machining processes.
AISI 431 is available in a wide range of forms to meet industrial needs:
· Hot rolled bars: Φ10mm-Φ130mm, with lengths of 5000-7000mm
· Hot forged bars: Φ140mm-Φ600mm, lengths of 2000-5800mm
· Plates/sheets: Thickness 2-250mm, width 310-1000mm
Surface finishes include turned, milled, ground (tolerance: +0/+0.05mm), and polished, with strict straightness (1mm/1000mm maximum) for precision components.
AISI 431’s unique properties make it indispensable across sectors:
· Automotive: Used in engine valves, turbocharger parts, and transmission shafts—its high strength resists wear under extreme engine pressures.
· Petrochemical: Ideal for valves, pump rotors, and pipe fittings, offering moderate resistance to industrial chemicals and hydrocarbons.
· Medical: Employed in surgical tools and temporary orthopedic implants, combining biocompatibility with the toughness to withstand sterilization.
· Energy: Selected for gas turbine components and nuclear fasteners, maintaining integrity at high temperatures and under mechanical stress.
· Marine: Used in propeller shafts and deck hardware, resisting saltwater corrosion better than standard carbon steels.
AISI 431 offers higher nickel content (1.25-2.50% vs. 420’s 0.5% maximum), resulting in better toughness and corrosion resistance. While 420 excels in hardness, AISI 431 provides a superior balance of strength and ductility, making it better for load-bearing parts.
Limited cold working is possible, but the alloy’s martensitic structure makes it more prone to work hardening. Annealing at 680-800℃ before cold forming helps maintain ductility.
Standard stock sizes (Φ10mm-Φ300mm bars) ship within 3 days. Custom forging or machining takes 2-4 weeks, depending on complexity.
Country | Standard | Grade |
USA | ASTM A276/276M | 431 |
EN | EN 10088-3 | X17CrNi16-2/1.4057 |
China | GB/T 1220 | 17Cr16Ni2 |
Japan | JIS G4303 | SUS431 |
Russia | GOST 5632-76 | 20X17H2 |
Grade | C | Si | Mn | P | S | Cr | Ni |
431 | 0.20 Max | 1.0 Max | 1.0 Max | 0.040 Max | 0.030 Max | 15-17 | 1.25-2.50 |
Grade | Tensile Strength | Yield Strength | Elongation | Hardness (HBW) |
17Cr16Ni2 | 900-1050 Mpa | 700 Mpa Min | 12% Min | 295 Max |
SUS431 | 780 Mpa Min | 590 Mpa Min |
