Stainless Steel 420J2
EN 420J2 · UNS S42000 · JIS SUS420J2 · GB 3Cr13
420J2 (SUS420J2, S42000, X30Cr13) is a high-carbon 420-type martensitic stainless that hardens by oil or air quench to 50–55 HRC.
Values for the Annealed condition
420J2 tempers and conditions
420J2 is supplied in 7 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault soft annealed / subcritical annealed bar, plate and strip | Default stock condition for machining, blanking and forming before hardening. | 400 | 700 | 20 | 220 HB | — |
Hardened and tempered to Rm 800–950 MPa | European mechanical-property class for tempered bar/forgings where ductility and machinability matter more than hardness. | 650 | 880 | 12 | 27 HRC | — |
annealed then cold drawn/ground bar and wire | Pick for close-tolerance shafts and wire where extra strength and a bright surface are wanted without heat treatment. | 700 | 850 | 12 | 26 HRC | — |
Quenched and tempered ≈ 300–350 °C | Slightly softer, tougher condition for shafts, pump sleeves and mould inserts that see impact. | 1,300 | 1,550 | 8 | 47 HRC | — |
quench 1000–1050 °C, temper 200–300 °C (≈ 48–52 HRC) | Standard service condition for blades, instruments and valve parts — best balance of hardness, strength and corrosion resistance. | 1,450 | 1,720 | 6 | 50 HRC | 24 W/m·K |
stress-relieve only | Maximum hardness for wear-only parts; brittle and residual-stressed, so a low temper/stress relief is normally applied. | 1,550 | 1,900 | 2 | 55 HRC | — |
Quenched and tempered ≈ 150–200 °C | Choose for knife blades, scissors and wear surfaces where edge retention outranks toughness. | 1,550 | 1,850 | 4 | 53 HRC | — |
What is 420J2?
420J2 (SUS420J2, S42000, X30Cr13) is a high-carbon 420-type martensitic stainless that hardens by oil or air quench to 50–55 HRC. It is the standard bar and plate grade for knives, scissors and polished mould inserts, stocked annealed, cold drawn, hardened and in several Q&T conditions; annealed material gives 400 MPa yield, 700 MPa tensile, 20% elongation and 220 HB. Corrosion resistance is moderate (score 40) and only realised in the hardened, passivated state; weldability is poor and machinability (48) is below free-machining 420F. Choose 420F when chip control matters more than polishability. 420J2 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,450°C (2,642 °F). 420J2 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 57% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi).
What is 420J2 used for?
- Cutlery and kitchen knives
- Surgical scalpels and instruments
- Polished plastic mould inserts
- Scissors and shear blades
- Valve seats and needle valves
- Shafts and wear pins
- Hand tool blades
Advantages
- High electrical conductivity — 3.1 % IACS, better than 99% of stainless steel grades
- Polishes to a fine finish — 85/100, better than 97% of stainless steel grades
- Low embodied carbon — 3.2 kg CO₂/kg, better than 95% of stainless steel grades
- Easy to machine — 48/100, better than 88% of stainless steel grades
- Conducts heat well — 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades
Limitations
- Needs corrosion protection — 40/100, worse than 93% of stainless steel grades
- Difficult to weld — 25/100, worse than 92% of stainless steel grades
- Limited ductility — 20%, worse than 79% of stainless steel grades
420J2 properties
Typical room-temperature values for 420J2-Annealed; bars are the position among stainless steel grades.
Physical3
420J2 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,450°C (2,642 °F).
Mechanical15
420J2 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 57% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
420J2 is rated for continuous service to 650°C (1,202 °F). It conducts heat at 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
420J2 conducts electricity at 3.1 % IACS, better than 99% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (40/100), worse than 93% of stainless steel grades.
Sustainability4
Producing a kilogram of 420J2 takes about 45 MJ of energy and emits 3.2 kg of CO₂ — less than 91% of stainless steel grades. Typical recycled content is 60%.
Manufacturability6
420J2's machinability is fair (48/100, better than 88% of stainless steel grades); weldability poor (25/100); formability fair (40/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. 420J2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 420J2
Is 420J2 easy to machine?
Machine in the annealed condition with sharp, rigid tooling, moderate speed and generous coolant; hardened parts above ~45 HRC need carbide or CBN, or should be finished by grinding/EDM.
Can 420J2 be welded?
Poor weldability — preheat 200–300 °C, use matching or 309/310 filler, and temper immediately after welding to avoid cracking of the hard martensite.
Can 420J2 be formed, bent or molded?
Only light cold bending/blanking in the annealed state; harden at 1000–1050 °C, quench in oil or air, then temper at 150–350 °C (avoid 400–550 °C temper embrittlement).
Manufacturability
The process limits FabDigit applies to 420J2. Every 420J2 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair48 / 100 |
|---|---|
| ISO material group | M.4 |
| Cutting speed (rough / finish) | 140 / 170 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1.5 mm |
| Drill depth limit | 4× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
420J2 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CJIS SUS420J2 / GB 3Cr13; EN X30Cr13 is 0.26–0.35 | 0.26 – 0.4 | 0.32 |
| Si | ≤ 1 | 0.4 |
| Mn | ≤ 1 | 0.5 |
| P | ≤ 0.04 | 0.02 |
| SEN limit 0.015; free-machining variants up to 0.030 | ≤ 0.03 | 0.01 |
| Cr | 12 – 14 | 13 |
| Niresidual allowance (JIS/GB) | ≤ 0.6 | 0.3 |
| Fe | balance |
What surface finishes work on 420J2?
Polishes to a mirror finish and is the standard choice for polished mould inserts; passivate or lightly oil after grinding, and consider hard chrome/PVD for extra corrosion or wear protection.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
Organic Coating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel 420J2 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 420J2 cost?
420J2 is a premium-cost stainless steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
420J2 — frequently asked
What is 420J2 used for?
420J2 is typically used for cutlery and kitchen knives, surgical scalpels and instruments, polished plastic mould inserts, scissors and shear blades, valve seats and needle valves and shafts and wear pins. In short: higher-carbon cutlery stainless.
What is the yield strength of 420J2?
420J2 has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 57% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is 420J2 easy to machine?
Reasonably — machinability is rated fair (48/100, better than 88% of stainless steel grades). Machine in the annealed condition with sharp, rigid tooling, moderate speed and generous coolant; hardened parts above ~45 HRC need carbide or CBN, or should be finished by grinding/EDM.
Can 420J2 be welded?
Not readily — weldability is rated poor (25/100). Poor weldability — preheat 200–300 °C, use matching or 309/310 filler, and temper immediately after welding to avoid cracking of the hard martensite.
What surface finishes work on 420J2?
Polishes to a mirror finish and is the standard choice for polished mould inserts; passivate or lightly oil after grinding, and consider hard chrome/PVD for extra corrosion or wear protection.
Can 420J2 be formed, bent or molded?
Only light cold bending/blanking in the annealed state; harden at 1000–1050 °C, quench in oil or air, then temper at 150–350 °C (avoid 400–550 °C temper embrittlement).
What is the maximum service temperature of 420J2?
420J2 is rated for continuous use to about 650°C (1,202 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 420J2 cost?
420J2 is a premium-cost stainless steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in 420J2?
Yes — 420J2 is available for CNC machining; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- JIS G 4303 — Stainless steel bars (SUS420J2) — JSA (2021)
- GB/T 1220 — Stainless steel bars (3Cr13/30Cr13) — SAC (2007)
- EN 10088-1 / 10088-3 — Stainless steels, X30Cr13 (1.4028) — CEN (2014)
- ASTM A276/A276M — Stainless steel bars and shapes (Type 420) — ASTM (2017)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Martensitic stainless 1.4028 / 420 bar and strip datasheets — Outokumpu / Sandvik (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.