SUS420J2 Martensitic Stainless Steel Plate/Coil
SUS420J2 Martensitic Stainless Steel Plate/Coil: JIS G4304 & G4305 Full Data Analysis
Comprehensive material data analysis for SUS420J2 martensitic stainless steel according to JIS G4304 and JIS G4305 standards, covering chemical composition, mechanical and physical properties, international equivalents, and processing guidelines.
Hot rolling (JIS G4304), cold rolling (JIS G4305), annealing, hardening and tempering, machining, forming
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SUS420J2 Martensitic Stainless Steel Plate/Coil Introduction
SUS420J2 is a high-carbon martensitic stainless steel defined under Japanese standards JIS G4304 (hot-rolled) and JIS G4305 (cold-rolled) for plates, sheets, and coils. It belongs to the 13% chromium family and offers excellent hardenability through heat treatment. After quenching and tempering, SUS420J2 achieves high hardness (up to ~50 HRC) combined with good corrosion resistance in mild environments. Key attributes include:
- High carbon content (0.26–0.40%) enabling martensitic transformation
- Good wear resistance and edge retention
- Moderate corrosion resistance comparable to other 400-series stainless steels
- Supplied typically in annealed condition for further processing
It is widely used for cutlery, surgical instruments, valve parts, and bearings. The material must be heat-treated by the end user to develop its full mechanical properties.
SUS420J2 Martensitic Stainless Steel Plate/Coil Chemical Composition
The chemical composition of SUS420J2 is specified in JIS G4304/G4305. The high carbon content promotes martensitic hardening, while chromium provides basic corrosion resistance. Phosphorus and sulfur are kept low to maintain toughness and hot workability. The limits given below represent the ladle analysis required by the standard.
| Element | Standard Value | Remarks |
|---|---|---|
| Carbon (C) | 0.26 – 0.40 | Key hardenability element |
| Silicon (Si) | ≤ 1.00 | Deoxidizer; higher values may affect ductility |
| Manganese (Mn) | ≤ 1.00 | Austenite stabilizer, improves hardenability |
| Phosphorus (P) | ≤ 0.040 | Impurity; controlled for toughness |
| Sulfur (S) | ≤ 0.030 | Impurity; low levels for better ductility |
| Nickel (Ni) | ≤ 0.60 | Residual element; not intentionally added |
| Chromium (Cr) | 12.00 – 14.00 | Primary corrosion-resistance element |
SUS420J2 Martensitic Stainless Steel Plate/Coil Thermal and Electrical Physical Properties
Physical properties are representative for martensitic stainless steel grade SUS420J2. These values are influenced by heat treatment condition and temperature. Data provided at room temperature unless otherwise indicated. The material exhibits moderate thermal conductivity and typical magnetic properties in all conditions.
| Property | Standard Value | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.75 | g/cm³ | 20 °C |
| Modulus of Elasticity (E) | 200 | GPa | 20 °C |
| Shear Modulus (G) | 77 | GPa | Estimated from E and ν |
| Poisson's Ratio (ν) | 0.27 – 0.30 | - | 20 °C |
| Thermal Expansion Coefficient (α) | 10.3 × 10⁻⁶ | /K | 20–100 °C |
| Thermal Conductivity (λ) | 24.9 | W/(m·K) | At 100 °C |
| Specific Heat Capacity (c) | 460 | J/(kg·K) | 20 °C |
| Electrical Resistivity (ρ_e) | 0.55 × 10⁻⁶ | Ω·m | 20 °C |
SUS420J2 Martensitic Stainless Steel Plate/Coil Mechanical Properties
Mechanical properties are typically measured in the annealed condition as supplied. Values may vary depending on product thickness. For final applications, hardening and tempering are performed to achieve desired hardness and strength. The data below represent minimum requirements from JIS G4304 for plates/coils unless otherwise noted.
| Property | Standard Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (Rp0.2) | ≥ 245 | MPa | Room temperature, annealed |
| Tensile Strength (Rm) | ≥ 540 | MPa | Room temperature, annealed |
| Elongation (A) | ≥ 18 | % | Gauge length 50 mm, thickness ≤ 6 mm, annealed |
| Hardness | ≤ 235 | HBW | Annealed; typical hardened value 45–52 HRC |
| Bend Test (Bending Angle / Bend Diameter) | 180° / 1t | - | Annealed, inner diameter = plate thickness (t); no cracks |
SUS420J2 Martensitic Stainless Steel Plate/Coil Exact Equivalent Grades and Substitutable Standards
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| International | ISO 683-17 | X30Cr13 | Identical composition range |
| Europe | EN 10088-2 / -3 | 1.4028 (X30Cr13) | Equivalent plate/strip grade |
| USA | ASTM A240 / A276 | 420 (UNS S42000) | C range broader (0.15 min); typical 420 with 0.30–0.40 C is interchangeable |
| China | GB/T 3280 / GB/T 1220 | 30Cr13 (3Cr13) | Same carbon and chromium limits |
| Germany (historical) | DIN 17440 | 1.4028 (X30Cr13) | Withdrawn but technically equivalent |
| UK (historical) | BS 970 Part 1 | 420S45 | Equivalent martensitic stainless |
SUS420J2 Martensitic Stainless Steel Plate/Coil Application Introduction
SUS420J2 is selected when a combination of good corrosion resistance and high hardness/strength is required. It is magnetic in all conditions and can be polished to a high finish. Typical applications:
- Cutlery and kitchen knives
- Surgical and dental instruments
- Valve seats, stems, and balls
- Bearings and races for mildly corrosive environments
- Measuring tools (calipers, rules)
- Pump shafts and wear-resistant parts
Product Applications: Knife blades and scissors, Surgical scalpels, forceps, and clamps, Gate, globe, and check valve internals, Ball bearing rings and rolling elements, Springs and spring washers for moderate temperatures, Gauges and reference blocks
Processed into products: Valve seats and stems, Shaft sleeves and pump impellers (for non-aggressive fluids), Wear plates and guides, Spring plates and disc springs, Surgical blade edges and dental burs, Pins, bushings, and fasteners requiring high strength
Application industries: Medical devices and healthcare, Cutlery and kitchenware manufacturing, Industrial valves and pumps, Precision engineering and metrology, Automotive components (decorative and functional)
SUS420J2 Martensitic Stainless Steel Plate/Coil Similar / Alternative Material Recommendations
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| Japan | JIS G4304 | SUS420J1 | Lower carbon (0.16–0.25); softer, better toughness, lower achievable hardness |
| Japan | JIS G4303 | SUS440A | Higher carbon (0.60–0.75); achieves higher hardness (up to 56 HRC) but less corrosion resistance |
| USA | ASTM A240 | 440A (UNS S44002) | Similar higher carbon alternative to SUS440A; used when greater wear resistance needed |
| Europe | EN 10088-2 | 1.4034 (X46Cr13) | Carbon 0.43–0.50; higher hardness than SUS420J2, used for cutlery and surgical tools |
| China | GB/T 3280 | 20Cr13 (2Cr13) | Softer, better corrosion resistance; used when toughness is prioritised over high hardness |
Notes:
Hardening and tempering are essential to develop the desired hardness and mechanical properties. Typical hardening temperature: 950–1050 °C with oil or air cooling; tempering between 150–400 °C depending on hardness requirements. Post-weld heat treatment is necessary to restore properties. Not recommended for highly corrosive environments (e.g., contact with chlorides or strong acids) without adequate maintenance. Confirm the exact specification and condition with the material supplier for critical applications.
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