Description
Stainless Steel Grade 420/1.4021 is a high-carbon martensitic stainless steel known for its high hardness and excellent corrosion resistance. It is often used in applications requiring a combination of high strength and moderate corrosion resistance. Grade 420 can be hardened through heat treatment to achieve a range of hardness levels and mechanical properties, making it versatile for various industrial uses.
Chemical Composition
Carbon (C): 0.15 - 0.40%
Chromium (Cr): 12.0 - 14.0%
Manganese (Mn): ≤ 1.0%
Silicon (Si): ≤ 1.0%
Sulfur (S): ≤ 0.03%
Phosphorus (P): ≤ 0.04%
Mechanical Properties
Tensile Strength: 655 - 980 MPa
Yield Strength: 345 MPa (minimum)
Elongation: 20% (in 50 mm)
Hardness (Rockwell C): 50 (annealed) to 60 (hardened)
Thermal & Physical Properties
Density: 7.74 g/cm³
Melting Ragne: 1450 - 1510 °C
Thermal Conductivity: 24.9 W/m•K (at 100°C)
Electrical Resistivity: 0.55 µΩ•m (at 20°C)
Specific Heat Capacity:460 J/kg•K (at 25°C)
Other Designations
DIN: 1.4021
UNS: S42000
ASTMA: A276, A580
EN: X20Cr13
JIS: SUS 420J1
Fabrication and Heat Treatment
Forming: Stainless steel 420/1.4021 can be formed using conventional methods, but requires more force than other stainless steels due to its higher strength and hardness.
Welding: This grade is not recommended for welding as it can be difficult to weld and may require preheating and post-weld heat treatment to prevent cracking.
Heat Treatment:
Annealing: Heat to 840-900°C, then cool slowly in the furnace to improve ductility and machinability.
Hardening: Heat to 980-1035°C, then quench in oil or air for maximum hardness.
Tempering: Heat to 150-370°C to reduce brittleness while maintaining hardness.
Applications
Cutlery: High hardness and sharpness retention make it ideal for knives and blades.
Surgical Instruments: Used in medical tools requiring high strength and corrosion resistance.
Industrial Blades: Suitable for various industrial cutting tools.
Valves and Pumps: Used in components exposed to water and other corrosive environments.
Gears and Bearings: Employed where high wear resistance and strength are essential.
Supplied Forms
Bars
Coils
Wires
Features
High Hardness: Achievable through heat treatment, making it suitable for cutting and wear-resistant applications.
Good Corrosion Resistance: Offers resistance to mild corrosive environments, although not as high as austenitic grades.
Excellent Wear Resistance: Suitable for applications with high friction and wear.
Versatile Heat Treatment: Can be annealed or hardened to achieve desired mechanical properties.
Magnetic Properties: 420 stainless steel is magnetic in all conditions.
