SUS420J1 Stainless Steel
Premium Martensitic Grade for Demanding Applications
SUS420J1 is a premium martensitic stainless steel renowned for its excellent hardenability, moderate corrosion resistance, and exceptional wear resistance. Characterized by a chromium content of 12.00–14.00% and a carefully controlled carbon range of 0.16–0.25%, this grade is specifically designed to be hardened through heat treatment. When quenched and tempered, SUS420J1 attains high mechanical strength and a durable cutting edge — making it an ideal choice for applications requiring both structural integrity and resistance to mild corrosive environments such as water, steam, and mild chemicals.
At FUSHUN METAL, we leverage decades of metallurgical expertise to produce SUS420J1 with superior internal cleanliness and consistent microstructure. Whether you require cold-rolled strips for precision blades or heavy forged bars for industrial machinery, our production capabilities ensure that every batch meets the most stringent international standards — making us a trusted partner for engineers and procurement managers worldwide.
Equivalent Grades
| Standard | Grade / Designation |
|---|---|
| JIS | SUS420J1 |
| EN / DIN | 1.4021 / X20Cr13 |
| ASTM / AISI | Type 420 (Low Carbon) / UNS S42000 |
| GB | 20Cr13 (Formerly 2Cr13) |
| GOST | 20X13 |
Applications
Thanks to its unique combination of hardness, toughness, and corrosion resistance, SUS420J1 is widely utilized across various demanding industries. Representative downstream products and application sectors are illustrated below.
Cutlery & Food Processing
Professional kitchen knife blades, scissors, food preparation utensils, and meat grinder blades where hygiene and edge retention are critical.
Medical & Surgical
Surgical scalpels, dental instruments, and medical forceps where precision, sharpness, and repeated sterilisation resistance are required.
Industrial Equipment
Cutting tools, industrial shear blades, and paper mill refiner plates operating under high abrasive wear conditions.
Mechanical Components
Pump shafts, valve spindles, hydraulic rams, and piston rings demanding dimensional stability under cyclic loading.
Fasteners & Hardware
High-strength bolts, nuts, screws, and precision measuring instruments where tight tolerances and durability are paramount.
Specifications & Standards
FUSHUN METAL supplies SUS420J1 and its equivalent grades in strict accordance with all major international standards. Products are manufactured, tested, and certified to the following specifications:
- JIS Standards: JIS G4303 (Stainless Steel Bars) — JIS G4304 (Hot-Rolled Stainless Steel Plate, Sheet, and Strip) — JIS G4305 (Cold-Rolled Stainless Steel Plate, Sheet, and Strip)
- ASTM Standards: ASTM A276 (Stainless Steel Bars and Shapes) — ASTM A240 (Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip) — ASTM A314 (Stainless Steel Billets and Bars for Forging)
- EN Standards: EN 10088-2 (Stainless Steels — Sheet, Plate and Strip) — EN 10088-3 (Stainless Steels — Semi-finished Products, Bars, Rods and Wire)
- GB Standards: GB/T 1220 (Stainless Steel Bars) — GB/T 3280 (Cold Rolled Stainless Steel Plate, Sheet, and Strip) — GB/T 4237 (Hot Rolled Stainless Steel Plate, Sheet, and Strip)
Available Sizes & Delivery
FUSHUN METAL operates a state-of-the-art 6,000-ton forging press and a GFM radial forging machine, enabling us to supply SUS420J1 in a highly versatile range of shapes and dimensions to meet your exact project requirements.
Available Shapes & Size Ranges
Delivery & Minimum Order Quantity (MOQ)
Ready Stock
Common sizes available for immediate shipment. MOQ: 1 piece — Lead time: approx. 7 days.
Custom Forgings & Rolled Products
Standard MOQ: 3 tons — Lead time: approx. 30 days.
Small Batch Special Melts
Flexible small induction furnaces. MOQ: 3–5 tons for custom melting runs.
Large Volume Orders
Processed via 30–60 ton Electric Arc Furnaces (EAF) for rapid delivery and maximum cost-efficiency.
Chemical Composition
The chemical composition is the foundation of SUS420J1's performance. The table below cross-references elemental limits across four major standard equivalents. Values that differ meaningfully from the JIS baseline are shown in bold italic.
| Standard / Grade | C (%) | Si (%) | Mn (%) | P (%) | S (%) | Cr (%) |
|---|---|---|---|---|---|---|
| JIS SUS420J1 | 0.16 – 0.25 | ≤ 1.00 | ≤ 1.00 | ≤ 0.040 | ≤ 0.030 | 12.00 – 14.00 |
| EN 1.4021 | 0.15 – 0.22 | ≤ 1.00 | ≤ 1.50 | ≤ 0.040 | ≤ 0.015 | 12.00 – 14.00 |
| GB 20Cr13 | 0.16 – 0.25 | ≤ 1.00 | ≤ 1.00 | ≤ 0.040 | ≤ 0.030 | 12.00 – 14.00 |
| ASTM Type 420 | ≥ 0.15 | ≤ 1.00 | ≤ 1.00 | ≤ 0.040 | ≤ 0.030 | 12.00 – 14.00 |
Note on deviations: EN 1.4021 imposes a stricter sulphur ceiling (≤ 0.015%) and permits a wider manganese allowance (≤ 1.50%) compared to the JIS, GB, and ASTM versions. ASTM Type 420 specifies a minimum carbon floor (≥ 0.15%) rather than a fixed range — customers specifying to ASTM A276 should clarify carbon upper limits separately to ensure equivalent hardenability.
Melting & Processing
At FUSHUN METAL, we understand that the purity of martensitic stainless steel directly impacts its fatigue life and polishing characteristics. Our standard melting route for SUS420J1 begins with an Electric Arc Furnace (EAF) for primary smelting, followed by Argon Oxygen Decarburization (AOD) to precisely control carbon and chromium levels. Ladle Furnace (LF) refining and Vacuum Degassing (VD) then minimize non-metallic inclusions and dissolved hydrogen content.
For applications requiring superior homogeneity and extreme fatigue resistance, we offer Electro-Slag Remelting (ESR) or Pressurized ESR (PESR). For aerospace-grade demands, Vacuum Induction Melting combined with Vacuum Arc Remelting (VIM + VAR) is available. Contact our engineering team to select the most cost-effective and performance-optimised melting route for your application.
Standard Melting Route
Premium Remelting Options (Available on Request)
Mechanical Properties
The mechanical properties of SUS420J1 vary significantly depending on the heat treatment condition. The following table lists guaranteed mechanical properties for the annealed state and typical quenched & tempered conditions, all measured at room temperature.
| Condition | 0.2% Proof Stress (MPa) | Tensile Strength (MPa) | Elongation (%) | Hardness |
|---|---|---|---|---|
| Annealed | ≥ 225 | ≥ 520 | ≥ 18 | ≤ 234 HV / ≤ 97 HRB |
| Q&T 700 | ≥ 500 | 700 – 850 | ≥ 13 | 215 – 260 HB |
| Q&T 800 | ≥ 600 | 800 – 950 | ≥ 11 | 240 – 295 HB |
Heat Treatment
Proper heat treatment is essential to achieving the desired balance of hardness, toughness, and corrosion resistance in SUS420J1. FUSHUN METAL can supply material in the fully annealed condition, or pre-hardened and tempered to a specified tensile range as agreed with the customer.
| Process | Temperature Range (°C) | Cooling Method | Resulting Microstructure / Hardness |
|---|---|---|---|
| Full Annealing | 745 – 825 | Slow furnace cooling | Ferrite + Carbide (Max 234 HV) |
| Hardening (Quenching) | 950 – 1,050 | Oil or Air cooling | Martensite (approx. 48–52 HRC before tempering) |
| Tempering — High Toughness | 600 – 750 | Air cooling | Tempered Martensite (700–950 MPa tensile) |
| Tempering — High Hardness | 150 – 250 | Air cooling | Stress-relieved Martensite (45–50 HRC) |
Surface Finish & Machining
FUSHUN METAL offers a comprehensive range of surface finishes tailored to your downstream manufacturing processes. Our advanced CNC machining centres allow us to deliver semi-finished parts directly to your assembly line. Selecting the appropriate surface condition at the supply stage can significantly reduce your internal processing costs and material waste.
| Finish Type | Applicable Form | Surface Roughness (Ra) | Dimensional Tolerance |
|---|---|---|---|
| Black (As-Forged / As-Rolled) | Bars, Plates | — | Standard mill tolerance |
| Peeled / Turned | Round Bars | ≤ Ra 3.2 µm | h11 |
| Centerless Ground | Round Bars | Ra 0.8 µm | h9 or h11 |
| Milled | Flat Bars, Blocks | Ra 3.2 µm | +0.1 / −0 mm |
Quality Assurance & Inspection
Quality is the cornerstone of FUSHUN METAL's operations. Our facilities are fully certified to ISO 9001 and AS9100 standards, ensuring rigorous quality control at every production stage — from raw material selection through to final dispatch.
- Non-Destructive Testing (NDT): 100% Ultrasonic Testing (UT) is performed on all forged products in accordance with SEP 1921 Class C/c or D/d and EN 10308, guaranteeing the absence of internal defects, seams, or segregation.
- Laboratory Testing: Comprehensive chemical analysis (OES), mechanical property testing (tensile, Charpy impact, hardness), and precise dimensional inspection are conducted on every heat number.
- Metallographic Examination: Microstructure analysis is performed to verify proper grain size, confirm a homogeneous tempered martensite matrix, and ensure the complete absence of detrimental carbide networks.
- Mill Test Certificate: All shipments are accompanied by an EN 10204 3.1 Mill Test Certificate (MTC). EN 10204 3.2 certification witnessed by independent third-party agencies — SGS, TÜV, or Lloyd's Register — is available upon request.
Packing & Shipping
Proper packaging is vital to preserving the integrity of stainless steel during global transit. Our meticulous four-stage packing protocol ensures your SUS420J1 arrives in pristine condition — completely free from rust or dimensional distortion — regardless of destination port.
Black Surface Bundling As-forged and as-rolled products are securely bundled with heavy-duty steel wire and reinforced to prevent shifting and contact damage inside the shipping container.
Anti-Rust Oil Coating All bright, turned, ground, and peeled surfaces are coated with premium anti-rust oil as the primary electrochemical barrier against moisture ingress.
VCI Paper & Plastic Film Wrap Materials are wrapped in Volatile Corrosion Inhibitor (VCI) paper and encased in thick plastic film to actively neutralise corrosive agents during extended sea freight.
Fumigated Wooden Crate Finished packages are placed in custom-built, ISPM-15 fumigated wooden crates designed to absorb physical impact and block marine humidity throughout the entire transit journey.
Frequently Asked Questions
Common technical and commercial questions from engineers and procurement teams. Contact us directly for enquiries not covered below.
Can you cut SUS420J1 to my specific length?
What is the hardness of SUS420J1 in the annealed condition?
Is SUS420J1 suitable for welding?
What is the maximum hardness achievable after quenching?
Ready to Source SUS420J1?
Contact our metallurgical engineers today for a free, no-obligation quote. From standard stock to fully customised forgings, we are ready to deliver the optimal SUS420J1 solution for your project.
