420J2 Stainless Steel
420J2 is a higher-carbon grade in the 420 martensitic family. It is selected for parts that need higher hardness, strong wear resistance, and a clean, polished surface. It is common for blades, cutting tools, and high-wear components in mild corrosion service.
As a martensitic stainless steel, 420J2 is heat treatable and magnetic. Final performance depends on heat treatment, section size, and surface finishing.
Carbon level
Higher C for higher hardness
Often 0.26–0.40% for SUS420J2 (by JIS reference).
Hardness after heat treatment
About 50–55 HRC
Typical after harden & temper (depends on section and cycle).
Wear performance
High wear resistance
Suitable for cutting edges and contact surfaces.
Surface capability
Very good polishability
Used for bright and fine brushed finishes.
420J2 is used where hardness and surface quality matter more than deep forming. It supports sharp edges, stable wear performance, and a clean appearance in daily use conditions.
- Blades and cutting tools: knives, scissors, cutters, trimming tools
- Medical and lab tools: selected instruments where cleaning and finish matter
- Measuring and precision parts: fixtures, small tooling parts
- Mechanical wear parts: shafts, pins, valve parts for mild environments
- Decorative hardware: trims and bright-finish components
420J2 may appear under different naming systems. Cross-references are helpful for sourcing, but the safest approach is to specify the target standard and required chemistry limits.
| System | Designation | Note |
|---|---|---|
| JIS | SUS420J2 | Common ordering name in Asia |
| EN | 1.4034 | Often used as an EU reference for high-carbon 420-type |
| DIN | X46Cr13 | German format naming for EN 1.4034 |
| GOST | 40Х13 | Seen in regional documents |
| GB | 4Cr13 | China naming format often used for similar supply routes |
| ASTM | Type 420 (high-carbon reference) | Frequently used as a document reference |
- High hardness potential: supports cutting edges and wear surfaces after heat treatment.
- Wear resistance: suitable for frequent contact and repeated service cycles.
- Good surface finish: supports bright, polished, or fine brushed appearance.
- Mild corrosion resistance: reliable in fresh water, steam, and indoor environments.
- Magnetic: magnetic in annealed and hardened conditions.
Limits vary by standard and revision. Use your project specification and the Mill Test Certificate for confirmation.
| Standard | C | Cr | Ni | Mn | Si | P | S | Fe |
|---|---|---|---|---|---|---|---|---|
| JIS G 4303 (SUS420J2) | 0.26–0.40 | 12.0–14.0 | ≤ 1.0 | ≤ 1.0 | ≤ 1.0 | ≤ 0.04 | ≤ 0.03 (some specs tighter) | Balance |
| EN 10088-2 (1.4034 / X46Cr13) | 0.43–0.50 | 12.5–14.5 | ≤ 1.0 | ≤ 1.0 | ≤ 1.0 | ≤ 0.04 | ≤ 0.015 (typical EN limit) | Balance |
| GB / GB/T 1220 (4Cr13) | 0.36–0.45 | 12.5–14.5 | — | — | ≤ 1.0 | ≤ 0.04 | ≤ 0.03 | Balance |
Values vary by product form and thickness. Use the governing standard for acceptance criteria.
| Standard | Tensile | Yield (0.2%) | Elongation | Hardness (HBW) |
|---|---|---|---|---|
| JIS G 4303 (SUS420J2) | ≥ 740 MPa | ≥ 300 MPa | ≥ 15% | ≤ 217 (annealed) |
| EN 10088-2 (1.4034) | ≥ 750 MPa | ≥ 300 MPa | ≥ 12% | ≤ 217 |
| GB / GB/T 1220 (4Cr13) | ≥ 750 MPa | ≥ 300 MPa | ≥ 12% | ≤ 217 |
420J2 performs well in fresh water, indoor air, steam, and many day-to-day environments. With proper finishing and cleaning, it maintains a stable stainless appearance in mild service.
Compared with 420J1, the higher carbon level can slightly reduce corrosion margin, especially if the surface is rough or not well cleaned. For intermittent heat exposure, 420J2 can resist oxidation up to about 650°C in many use cases.
420J2 can be supplied in common stainless product forms. Availability depends on finish, tolerance, straightness, and inspection scope. Share your sizes and end use to match the right supply route.
| Form | Typical size range | Notes |
|---|---|---|
| Sheet (cold rolled) | 0.3–6.0 mm, width 1000–2000 mm | Common for polished parts and cut blanks |
| Plate (hot rolled) | 3–100 mm, width 1000–2000 mm | Machining stock and heavier sections |
| Coil | 0.3–6.0 mm, width 1000–2000 mm | Slitting and cut-to-length available |
| Strip | 0.3–10 mm, width 7–600 mm | Often used for formed parts and small components |
| Seamless pipe | OD ≤ 610 mm, WT 1–100 mm | Confirm NDT requirements if needed |
| Welded pipe | OD 6–3000 mm, WT 1–100 mm | Define weld type and surface requirements |
| Round bar | Diameter 1–200 mm, length 100–12000 mm | Common for machining and heat-treated parts |
| Flat bar | Width 20–800 mm, thickness 3–60 mm | Cut stock for tools and fixtures |
| Angle bar | Side 20–250 mm, thickness 3–35 mm | Common for frames and supports (by project request) |
| Channel / H beam | Channel 50–400 mm; H beam 100–1000 mm | Define size, tolerance, and straightness |
- Machining: best in annealed condition. Use rigid tooling and coolant for stable finish.
- Forming: fair formability in annealed state; not a good choice for deep drawing.
- Welding: generally avoided for critical parts due to cracking risk. If required, use controlled procedures.
- Heat treatment: harden and temper to the target hardness window; control distortion by section size and fixturing.
- Surface finishing: polishing and brushing can deliver a clean, reflective surface.
The ranges below are used as a practical reference. The right cycle depends on section size, hardness target, and distortion control requirements.
| Step | Typical range | Purpose |
|---|---|---|
| Anneal | 815–900°C, slow furnace cool | Softens for machining and reduces stress |
| Harden | 980–1050°C, oil or air quench | Builds hardness and strength |
| Temper | 150–370°C | Balances hardness with toughness |
These grades are closely related. 420J2 is commonly selected when higher hardness and wear resistance are the priority. 420J1 is selected when ductility and polishability are the main goal. Standard 420 is a general-purpose option.
| Topic | 420J1 | 420J2 | 420 |
|---|---|---|---|
| Carbon (typical) | 0.15–0.25% | 0.26–0.40% | 0.15–0.40% |
| Hardness potential (HRC) | 40–50 | 50–55 | 45–55 |
| Ductility | Better | Lower | Medium |
| Polishability | Excellent | Very good | Good |
| Typical use | Tableware, decorative parts | Blades, cutters, wear parts | General engineering parts |
A clear RFQ helps reduce lead time and improves consistency across batches.
- Grade and standard: SUS420J2 / EN 1.4034 / GB 4Cr13 (as applicable)
- Condition: annealed, hardened, tempered (state your hardness target if needed)
- Form and size: thickness/width/length or OD/WT and tolerance
- Surface finish: 2B, BA, polished, mirror, brushed (define direction if required)
- Inspection: Mill Test Certificate, third-party inspection, NDT (if required)
- Packing: protective film, paper interleave, seaworthy packing, crating
Use these internal tools to confirm equivalents, check hardness, and prepare a clear RFQ.
Is 420J2 stainless steel magnetic?
Yes. 420J2 is martensitic stainless steel, so it is magnetic in both annealed and hardened conditions.
What hardness can 420J2 reach?
After proper hardening and tempering, 420J2 commonly reaches about 50–55 HRC. Final results depend on section size and tempering temperature.
What is the difference between 420J2 and 420J1?
420J2 has higher carbon. This supports higher hardness and wear resistance. 420J1 is more ductile and often easier to form and polish.
Is 420J2 suitable for food-contact tools?
It is widely used for kitchen tools such as knives and scissors. Final suitability depends on surface finish, cleaning practice, and local compliance requirements for your market.
What information helps you quote faster?
Grade and standard, product form, size and tolerance, surface finish, quantity, required tests, packing request, and destination port. If you need heat treated material, include the hardness window.
