Stainless Steel 420 (UNS S42000)
Stainless Steel 420 is a high-carbon martensitic stainless steel that is essentially a higher-carbon version of Type 410. The increased carbon content allows this alloy to be heat-treated to significantly higher hardness levels, reaching up to 50 HRC or more. While it offers moderate corrosion resistance, its primary value lies in its exceptional strength, wear resistance, and edge-retention capabilities.
At Aries Alloys, we supply Stainless Steel 420 to industries that demand "tool-steel" performance with the added benefit of stainless properties. It is the premier choice for surgical instruments, high-end cutlery, and heavy-duty industrial valves.
Key Performance Benefits
- Exceptional Hardness: Capable of being hardened to peak levels, providing superior resistance to deformation and surface wear.
- Excellent Edge Retention: High carbon levels ensure that blades and cutting tools stay sharp even under heavy use.
- Quench and Temper Versatility: Can be heat-treated to balance hardness with toughness depending on the specific application needs.
- Moderate Corrosion Resistance: Provides reliable protection against fresh water, mild acids, alkalis, and food acids when in the fully hardened and polished condition.
- High Mechanical Strength: Offers massive tensile and yield strength, making it suitable for highly stressed mechanical components.
Technical Profile & Composition
The Carbon-Chromium Balance:
Type 420 contains a minimum of 12% Chromium, which is sufficient to provide stainless properties, but the defining element is the Carbon (0.15%). This carbon allows for a full martensitic transformation during heat treatment, resulting in a dense, hard crystalline structure.
Mechanical & Physical Data:
- Density: 7.80 g/cm^3
- Magnetic Property: Strongly magnetic in all conditions.
- Thermal Conductivity: High thermal conductivity compared to austenitic (300-series) steels.
- Corrosion Note: For maximum corrosion resistance, Type 420 must be fully hardened, stress-relieved, and surface-polished to a mirror finish to prevent the formation of localized pits.
Primary Industrial Use Cases
Aries Alloys provides Stainless Steel 420 for high-precision and high-wear applications:
- Medical & Dental: Surgical instruments, dental scrapers, and laboratory tools that require repeated sterilization and sharp edges.
- Cutlery & Hand Tools: Professional chef knives, scissors, and specialized industrial blades.
- Oil & Gas Refineries: Pump shafts, valve internal components, and needle valves handling mildly corrosive media.
- Aerospace & Defense: Bushings, fasteners, and structural parts that require high hardness.
- Automotive: Specialized brake discs and engine components where wear resistance is critical.
Available Product Forms at Aries Alloys
We stock and supply Stainless Steel 420 in accordance with ASTM A276 and A240:
- Round & Hex Bars: Precision rods for machining high-hardness shafts, surgical tools, and fasteners.
- Sheets & Plates: Durable flat products for the manufacturing of industrial knives and wear-resistant liners.
- Custom Forgings: Blocks and rings tailored for high-pressure valve bodies and heavy-duty machinery.
- Precision Ground Flats: Ready-to-use plates for tool and die applications.