420 Martensitic Stainless Steel Sheet Hot rolled / cold rolled 0.4mm - 100mm Thickness
420 stainless steel plate is a martensitic stainless steel with higher carbon content than grade 410, designed for applications requiring excellent hardness, wear resistance, and moderate corrosion resistance. It can be heat-treated to achieve a hardness of up to 50 HRC, making it the hardest among the 12% chromium grades.
Grade 420 stainless steel is widely used in cutlery, surgical instruments, pump shafts, valve components, bearings, and plastic molding tools. Its combination of high strength, good polishability, and cost-effectiveness makes it a popular choice across multiple industries.
Key Features
| Feature | Description |
|---|---|
| Type | Martensitic stainless steel |
| Hardness (heat-treated) | Up to 50 HRC |
| Yield Strength | ≥379 MPa (55 KSI) as annealed |
| Tensile Strength | ≥689 MPa (100 KSI) as annealed |
| Corrosion Resistance | Moderate, best achieved in hardened condition |
| Magnetic | Yes (due to martensitic structure) |
| Weldability | Not recommended due to hardening properties |
| Machinability | Good in annealed condition (50% rating) |
Equivalent Designations
| Standard | Grade |
|---|---|
| AISI | 420 |
| UNS | S42000 |
| EN / DIN | 1.4021 / X20Cr13 |
| JIS | SUS420J1 / SUS420J2 |
| GB | 20Cr13 / 30Cr13 |
Note: Different standards specify varying carbon ranges for 420-type grades:
AISI 420 / UNS S42000: 0.15% carbon minimum
EN 1.4021 (X20Cr13): 0.16-0.25% carbon
SUS420J1: 0.16-0.25% carbon
SUS420J2: 0.26-0.40% carbon (higher hardness)
Specifications & Size Range
| Parameter | Range |
|---|---|
| Thickness | 0.4 mm – 100 mm (custom up to 300 mm available) |
| Width | 3 mm – 3500 mm |
| Length | 1000 mm – 12000 mm (custom available) |
| Production Method | Hot rolled or cold rolled |
| Standard | ASTM A240/A480, EN 10088-2, JIS G4304/G4305 |
Surface Finishes
| Finish | Code | Characteristics | Application |
|---|---|---|---|
| No.1 | Hot rolled, annealed & pickled | Original industrial surface | Industrial equipment, thick plates |
| 2B | Cold rolled, bright finish | Smooth, reflective | General fabrication, kitchen equipment |
| BA | Bright annealed | Mirror-like reflectivity | Decorative applications |
| No.4 | Brushed | Matte, fine satin finish | Architectural, food processing |
| HL | Hairline | Continuous linear streaks | Building facades |
| 8K | Mirror | Highly reflective | Luxury finishes |
Chemical Composition
Standard 420 (AISI / UNS S42000)
| Element | Content (%) |
|---|---|
| Carbon (C) | 0.15 – 0.46 |
| Chromium (Cr) | 12.0 – 14.0 |
| Manganese (Mn) | ≤1.50 |
| Silicon (Si) | ≤1.00 |
| Phosphorus (P) | ≤0.040 |
| Sulfur (S) | ≤0.030 |
| Iron (Fe) | Balance |
SUS420J1 (JIS Standard)
| Element | Content (%) |
|---|---|
| Carbon (C) | 0.16 – 0.25 |
| Chromium (Cr) | 12.0 – 14.0 |
| Manganese (Mn) | ≤1.00 |
| Silicon (Si) | ≤1.00 |
| Phosphorus (P) | ≤0.040 |
| Sulfur (S) | ≤0.030 |
| Nickel (Ni) | ≤0.60 |
SUS420J2 (Higher Carbon Version)
| Element | Content (%) |
|---|---|
| Carbon (C) | 0.26 – 0.40 |
| Chromium (Cr) | 12.0 – 14.0 |
| Manganese (Mn) | ≤1.00 |
| Silicon (Si) | ≤1.00 |
Mechanical Properties (Annealed Condition)
| Property | Value |
|---|---|
| Tensile Strength | ≥689 MPa (100 KSI) |
| Yield Strength (0.2% offset) | ≥379 MPa (55 KSI) |
| Elongation | 15% (in 2 inches) |
| Hardness (Brinell) | ≤223 HBW |
| Hardness (Rockwell) | ≤97 HRB |
| Shear Strength | 420 MPa (61 KSI) |
| Density | 7.70 – 8.00 g/cm³ |
| Modulus of Elasticity | 200 – 215 GPa |
| Melting Point | 1450 – 1510°C (2640 – 2750°F) |
| Machinability | 50% of 1212 carbon steel |
| Electrical Conductivity | 3% IACS |
Physical Properties
| Property | Value |
|---|---|
| Coefficient of Thermal Expansion (20-200°C) | 10.5 × 10⁻⁶ /°C |
| Thermal Conductivity (20°C) | 30.0 W/m·K |
| Specific Heat | 460 J/kg·K |
| Modulus of Elasticity (20°C) | 215 GPa |
Fabrication Guidelines
Machining
420 stainless steel offers good machinability in the annealed condition (50% rating). Use rigid tooling and sharp cutting edges. Hardened material is significantly more difficult to machine.
Welding
Not recommended due to hardening properties. If welding is absolutely necessary, special procedures and preheating are required, followed by immediate heat treatment.
Hot Working
Can be forged or hot worked at temperatures between 950°C and 1120°C, followed by slow cooling.
Polishing
Excellent polishability makes 420 suitable for decorative and high-finish applications.
Forming
Good ductility in the annealed condition allows for moderate forming operations.
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