SUS420J2 Martensitic Stainless Steel — Product Overview
SUS420J2 is a premium martensitic stainless steel renowned for its excellent balance of high hardness, wear resistance, and moderate corrosion resistance. Characterized by a chromium content of 12.00% to 14.00% and a moderately high carbon content (0.26% to 0.40%), this grade offers superior hardenability compared to lower-carbon martensitic alternatives such as SUS410. Thanks to its cost-effectiveness and versatile mechanical features, it is widely utilized across numerous demanding industrial fields.
When supplied in the annealed condition, SUS420J2 contains completely spheroidized carbides, ensuring excellent machinability and formability for complex component manufacturing. Its peak performance — specifically its optimal corrosion resistance and maximum mechanical strength — is achieved after hardening, tempering, and surface polishing. Whether you are manufacturing precision medical instruments or durable industrial molds, this grade delivers reliable performance. FUSHUN METAL provides premium SUS420J2 materials tailored to your specific project requirements.
Equivalent Grades
| Standard System | Designation / Grade |
|---|---|
| JIS (Japan) | SUS420J2 |
| AISI / ASTM (USA) | 420 / UNS S42000 |
| EN / DIN (Europe) | X30Cr13 / 1.4028 |
| BS (UK) | 420S45 |
| GB (China) | 30Cr13 (formerly 3Cr13) |
Applications
Due to its high hardness and excellent edge retention after heat treatment, SUS420J2 is specifically engineered for applications requiring both wear and corrosion resistance. Typical downstream products span five primary sectors.
Medical & Surgical Instruments
Scalpels, dental tools, forceps, and bone saws benefit from the grade's fine-grained hardened microstructure, enabling clean cutting edges and reliable performance in sterilization environments. The combination of hardness and polishability supports strict hygienic requirements in clinical settings.
High-End Cutlery & Blades
Professional kitchen knives, industrial scissors, shears, and razor blades demand the high hardness and sustained edge retention that SUS420J2 delivers after low-temperature tempering. Its aesthetic polishability further makes it a preferred choice for premium consumer cutlery.
Industrial Components
Pump shafts, valve components, nozzles, and hydraulic rams operating in mildly corrosive environments leverage the grade's combination of tensile strength and moderate corrosion resistance, reducing maintenance cycles in process industries.
Tooling & Molding
Plastic injection molds — especially for corrosive plastics such as PVC — mold bases, and extrusion dies rely on SUS420J2's polishability and dimensional stability under repeated thermal cycling. The grade's moderate alloy cost also makes it economical for large mold blocks.
Precision Mechanical Parts
Bearings, gears, measuring instruments, and hand tools manufactured from this grade benefit from consistent hardness across cross-sections and the tight dimensional tolerances achievable through FUSHUN METAL's in-house grinding and CNC machining services.
Specifications & Standards
FUSHUN METAL supplies SUS420J2 in strict accordance with global manufacturing standards, ensuring full compatibility with your engineering specifications. The grade is officially covered under the following standard systems and product forms:
- JIS G4303 — Stainless Steel Bars
- JIS G4304 / G4305 — Hot-rolled / Cold-rolled Stainless Steel Plates and Sheets
- ASTM A276 / A314 — Stainless Steel Bars and Shapes / Billets and Bars for Forging
- EN 10088-3 — Stainless Steels: Semi-finished products, bars, rods, wire, and sections
- GB/T 1220 — Stainless Steel Bars
Available Sizes & Delivery
FUSHUN METAL boasts robust manufacturing capabilities, equipped with a 6,000-ton open-die forging press and an advanced GFM radial forging machine. This allows us to offer an exceptionally wide range of sizes and product forms with superior internal soundness across all dimensions.
Supply Capabilities
Delivery & Minimum Order Quantity (MOQ)
| Order Type | MOQ | Lead Time |
|---|---|---|
| Ready Stock (Common Grades) | 1 piece | ~7 days |
| Custom Forged / Rolled Materials | 3 tons | ~30 days |
| Small Batch Special Melts (Induction Furnace) | 3 – 5 tons | Confirmed on inquiry |
| Large Volume Orders (EAF — 30 to 60 t) | Bulk | Fast; confirmed on inquiry |
Chemical Composition
The chemical composition is strictly controlled throughout the melting process. The table below compares elemental requirements across different standard designations. Bold values highlight the primary variations in limits between regional standards.
| Designation | C (%) | Si (%) | Mn (%) | P (%) | S (%) | Cr (%) |
|---|---|---|---|---|---|---|
| SUS420J2 | 0.26 – 0.40 | ≤ 1.00 | ≤ 1.00 | ≤ 0.040 | ≤ 0.030 | 12.00 – 14.00 |
| AISI 420 | ≥ 0.15 | ≤ 1.00 | ≤ 1.00 | ≤ 0.040 | ≤ 0.030 | 12.00 – 14.00 |
| X30Cr13 | 0.26 – 0.35 | ≤ 1.00 | ≤ 1.50 | ≤ 0.040 | ≤ 0.015 | 12.50 – 14.50 |
| 30Cr13 | 0.26 – 0.35 | ≤ 1.00 | ≤ 1.00 | ≤ 0.040 | ≤ 0.030 | 12.00 – 14.00 |
Melting & Processing Routes
At FUSHUN METAL, material purity directly impacts the fatigue life and polishability of the final product. We offer flexible, multi-tier melting routes tailored to your specific application requirements. Consult our engineers to determine the most cost-effective metallurgical solution for your project.
EAF + AOD + LF + VD
Standard production route. Electric Arc Furnace (EAF) smelting with Argon Oxygen Decarburization (AOD), followed by Ladle Furnace (LF) refining and Vacuum Degassing (VD). Ensures precise chemistry, low gas content, and consistent mechanical properties for general industrial and mold applications.
ESR / Pressurized ESR (PESR)
Electro-Slag Remelting (ESR) or Pressurized ESR (PESR) for enhanced cleanliness, refined inclusion morphology, and superior mirror polishing properties. Recommended for plastic injection mold and medical device applications demanding maximum surface quality and fatigue performance.
VIM + VAR
Vacuum Induction Melting (VIM) coupled with Vacuum Arc Remelting (VAR) for absolute maximum cleanliness, minimal macro-segregation, and the highest structural integrity. Available for aerospace-grade or critical medical standards where no compromise on material purity is acceptable.
Mechanical Properties
The mechanical properties of SUS420J2 vary significantly depending on the heat treatment condition. All data below represent typical values measured at room temperature and serve as reference values for design purposes.
| Condition | Hardness | Tensile Strength Rm | Yield Strength Rp0.2 | Elongation A | Reduction of Area Z |
|---|---|---|---|---|---|
| Annealed | 150 – 225 HB (~150 – 235 HV) | 540 – 655 MPa | ≥ 225 MPa | ≥ 20% | ≥ 50% |
| Q&T — High-Temp Temper | 280 – 320 HV | 880 – 1,030 MPa | ≥ 650 MPa | 10 – 15% | ≥ 40% |
| Q&T — Low-Temp Temper | 48 – 53 HRC | ≥ 1,400 MPa | ≥ 1,000 MPa | ≥ 8% | — |
Heat Treatment Guidelines
Proper heat treatment is critical to unlocking the full potential of SUS420J2, particularly its hardness and corrosion resistance. The parameters below are guidelines; section size and furnace characteristics should be considered when setting actual processing parameters.
| Process | Temperature (°C) | Holding Time | Cooling Method | Resulting Structure / Hardness |
|---|---|---|---|---|
| Annealing | 800 – 900 | 2 – 4 hours (section-dependent) | Slow furnace cool to 600°C, then air cool | Spheroidized carbides, ≤ 225 HB |
| Hardening (Quenching) | 980 – 1,040 | 30 – 60 min after through-heating | Oil or forced air | Untempered martensite, ~50 – 55 HRC |
| Tempering — For Hardness | 150 – 250 | ≥ 2 hours | Air cooling | Stress-relieved martensite, 48 – 53 HRC |
| Tempering — For Toughness | 600 – 700 | ≥ 2 hours | Air cooling | Tempered martensite, 28 – 34 HRC |
Surface Finish & Machining
FUSHUN METAL provides a comprehensive array of surface finishes and in-house machining options to minimize your secondary processing costs. All finishes are available in both as-annealed and hardened-and-tempered supply conditions.
Black (As-Forged / As-Rolled) Surface
Raw black scale surface for maximum cost efficiency. Dimensional tolerances are per rolling or forging standards. Suitable where surface condition is not a primary requirement and near-net-shape geometry is acceptable before your own machining operations.
Peeled / Turned Finish
Surface decarburization layer and minor defects fully removed by lathe turning. Achieves Ra 3.2 – 6.3 μm roughness. Ideal for round bars requiring tighter dimensional control before grinding or final machining at your facility.
Precision Milled (Flat Bars & Blocks)
Face milling provides a bright, squared finish with excellent flatness and perpendicularity. The preferred supply condition for mold base blocks and tooling blanks where geometric accuracy and a clean reference surface are essential for subsequent EDM or machining operations.
Centerless Ground / CNC Machined
Our centerless grinding service achieves dimensional tolerances up to h9/h11 with surface roughness Ra 0.8 – 1.6 μm. CNC machining is available for custom profiles, bored holes, and stepped components. These options are optimal for high-precision applications that require minimal further processing upon receipt.
Quality Assurance & Inspection
Quality is the cornerstone of FUSHUN METAL. Our manufacturing facilities are fully certified to ISO 9001 and AS9100 standards, ensuring rigorous quality control at every production stage — from raw material intake to final dispatch.
Non-Destructive Testing (NDT)
100% Ultrasonic Testing (UT) on all forged and rolled products, executed per SEP 1921 Class C/c or D/d standards. Ensures full internal soundness and detection of subsurface discontinuities prior to shipment.
Laboratory Analysis
Comprehensive chemical composition verification via Optical Emission Spectrometry (OES), mechanical property testing (tensile, impact, hardness), and metallographic examination to verify grain size and carbide distribution against specification.
Mill Test Certificate
Every shipment is accompanied by an EN 10204 3.1 Mill Test Certificate as standard. EN 10204 3.2 certification endorsed by an authorized third-party inspection body is available upon request at order placement.
Third-Party Inspection
We welcome and routinely accommodate pre-shipment inspections by internationally recognized agencies including SGS, TÜV, and Lloyd's Register. Coordination is handled by our dedicated quality team.
Packing & Shipping
We employ meticulous packaging protocols to ensure your material arrives in pristine condition regardless of global destination. Anti-rust treatments are specifically formulated to withstand harsh, high-humidity marine environments during ocean freight.
Black Surface Products
Materials are securely bundled with heavy-duty steel wire and reinforced end-protection plates to prevent shifting and edge damage during container transit. Bundle weight and dimensions are optimized for standard 20-foot and 40-foot container loading.
Bright, Ground, or Machined Surface Products
Multi-layered protection is applied as standard: materials are coated with premium anti-rust oil, individually wrapped in waterproof VCI nylon film or canvas, and securely packed in fumigated wooden boxes or crates. This preserves surface roughness Ra values and dimensional precision throughout the full logistics chain.
Export Compliance
All wooden packing materials comply with ISPM 15 (International Standards for Phytosanitary Measures) phytosanitary requirements, ensuring smooth customs clearance in all major import markets including the EU, USA, Australia, and Japan.
Frequently Asked Questions
Can you cut SUS420J2 to my specific length or size?
Yes. FUSHUN METAL is equipped with advanced band saws and CNC cutting equipment. We can cut round bars, flat bars, and blocks to your exact specified dimensions, saving you time and initial processing costs. Sawcut surfaces can be further faced or milled to a clean finish upon request.
What is the hardness of SUS420J2 in the annealed condition versus the hardened condition?
In the annealed (delivery) condition, hardness is typically below 225 HB (approximately 200 HV), making it easy to machine with standard tooling. After proper hardening and low-temperature tempering, it can achieve 48 to 53 HRC, providing excellent wear resistance for cutting tools, surgical instruments, and molds.
Does SUS420J2 have good corrosion resistance?
It has moderate to good corrosion resistance, but performance is highly condition-dependent. The best corrosion resistance is achieved when the steel is fully hardened, tempered, and the surface is finely ground or polished to a high Ra value. In the annealed state, the passive film is less stable and corrosion resistance is significantly lower. It is not recommended for aggressive chloride environments.
What is the difference between SUS420J1 and SUS420J2?
The primary difference lies in carbon content. SUS420J1 has a lower carbon range (0.16 – 0.25%), offering better toughness and slightly better corrosion resistance but a lower maximum achievable hardness. SUS420J2 has a higher carbon range (0.26 – 0.40%), allowing it to reach greater hardness levels. This makes SUS420J2 the preferred choice for cutting tools, surgical instruments, and wear-resistant mold components where maximum hardness is the primary design criterion.
Request a Free Quote for SUS420J2
FUSHUN METAL is your trusted source for premium SUS420J2 martensitic stainless steel. Share your dimensions, tolerances, and quantity requirements — our sales engineers will respond within 24 hours with a competitive, project-specific quotation.
Send Your Inquiry NowOr contact us directly — Email: info@fushunspecialsteel.com | Tel: +86-731-89903933
