Steel SNCM220
JIS SNCM220
SNCM220 is a low-carbon nickel-chromium-molybdenum case-hardening steel from the JIS SNCM family, equivalent to SAE 8620 and 20CrNiMo, carburized to give a hard case over a tough core.
Values for the HR condition
SNCM220 tempers and conditions
SNCM220 is supplied in 7 conditions, soft to hard. HR 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 |
|---|---|---|---|---|---|---|
900–925 °C air cool | Standard pre-treatment to refine grain and homogenize structure for uniform case depth and low carburizing distortion. | 360 | 630 | 26 | 183 HB | 8.5 % IACS |
HRDefault Hot rolled | Default stock condition for carburizing-grade bar that will be machined and then case hardened. | 385 | 560 | 29 | 160 HB | 8.5 % IACS |
full/spheroidize anneal, softest condition | Use when maximum softness and machinability or cold forming (cold heading, deep boring) is required before carburizing. | 385 | 535 | 31 | 149 HB | 8.7 % IACS |
Cold rolled | Choose for thin strip or stamped/formed carburizing parts needing good surface and tight thickness tolerance. | 520 | 640 | 15 | 195 HB | 8.5 % IACS |
Cold drawn | Pick for straight, size-accurate bright bar for automatic screw-machine work before carburizing. | 570 | 680 | 15 | 200 HB | 8.5 % IACS |
Quenched and tempered | Direct-hardened condition for shafts and fasteners used without carburizing, or as specified core strength after case hardening. | 720 | 880 | 19 | 29 HRC | — |
case 58–62 HRC, tempered ~170 °C | The intended service condition: gas-carburized 0.5–1.5 mm case for gear-tooth wear and contact-fatigue resistance with a tough core. | 800 | 1,050 | 12 | 60 HRC | 8 % IACS |
What is SNCM220?
SNCM220 is a low-carbon nickel-chromium-molybdenum case-hardening steel from the JIS SNCM family, equivalent to SAE 8620 and 20CrNiMo, carburized to give a hard case over a tough core. It is very widely used in Japan for automotive gears and is stocked as hot-rolled, cold-rolled, cold-drawn, annealed and normalized bar; in the default condition it shows about 385 MPa yield, 560 MPa tensile, 29 % elongation and 160 HB. There is no corrosion resistance without a coating, and once carburized the case can only be ground, so rough machining must precede heat treatment. 4820 gives higher core toughness for heavier gear loading. SNCM220 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). SNCM220 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 65% of steel grades. Elongation at break is 29% and the elastic modulus is 205 GPa (29.7 Msi).
What is SNCM220 used for?
- Gears
- Industrial drive shafts
- Pins
Advantages
- Ductile — tolerates forming and impact — 29%, better than 91% of steel grades
SNCM220 properties
Typical room-temperature values for SNCM220-HR; bars are the position among steel grades.
Physical3
SNCM220 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
SNCM220 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 65% of steel grades. Elongation at break is 29% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SNCM220 is rated for continuous service to 400°C (752 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
SNCM220 conducts electricity at 8.5 % IACS, better than 63% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of SNCM220 takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability7
SNCM220's machinability is good (55/100, better than 62% of steel grades); weldability good (55/100); formability good (60/100).
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 steel family
Yield strength against density for every steel grade FabDigit runs. SNCM220 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SNCM220
Is SNCM220 easy to machine?
Machines well in normalized or cold-drawn condition (~65 % of 1212); use carbide, generous coolant and rough before carburizing since the case is only grindable afterwards.
Can SNCM220 be welded?
Weldable with low-hydrogen consumables; preheat 150–250 °C for heavy sections and stress relieve/re-normalize — do not weld carburized surfaces.
Can SNCM220 be formed, bent or molded?
Good cold heading and bending in the annealed state; hot forge 1150–1200 °C and finish above 900 °C, then normalize before machining.
Manufacturability
The process limits FabDigit applies to SNCM220. Every SNCM220 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better55 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better60 / 100 |
|---|---|
| Weldability | Better55 / 100 |
SNCM220 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 |
|---|---|---|
| C | 0.17 – 0.23 | 0.2 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Ni | 0.4 – 0.7 | 0.55 |
| Cr | 0.4 – 0.65 | 0.5 |
| Mo | 0.15 – 0.3 | 0.22 |
| Curesidual, max | ≤ 0.3 | |
| Fe | balance |
What surface finishes work on SNCM220?
Requires protection — black oxide, phosphate, zinc or oil after carburizing; ground case surfaces polish well but corrode quickly if left bare.
Surface treatments FabDigit runs on 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
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel SNCM220 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does SNCM220 cost?
SNCM220 is a standard-cost steel ($$), cheaper than about 71% 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.
SNCM220 — frequently asked
What is SNCM220 used for?
SNCM220 is typically used for gears, industrial drive shafts and pins. In short: carburizing Ni-Cr-Mo bar.
What is the yield strength of SNCM220?
SNCM220 has a typical yield strength of 385 MPa (55.8 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 65% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is SNCM220 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines well in normalized or cold-drawn condition (~65 % of 1212); use carbide, generous coolant and rough before carburizing since the case is only grindable afterwards.
Can SNCM220 be welded?
Yes — weldability is rated good (55/100). Weldable with low-hydrogen consumables; preheat 150–250 °C for heavy sections and stress relieve/re-normalize — do not weld carburized surfaces.
What surface finishes work on SNCM220?
Requires protection — black oxide, phosphate, zinc or oil after carburizing; ground case surfaces polish well but corrode quickly if left bare.
Can SNCM220 be formed, bent or molded?
Good cold heading and bending in the annealed state; hot forge 1150–1200 °C and finish above 900 °C, then normalize before machining.
What is the maximum service temperature of SNCM220?
SNCM220 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SNCM220-HR and SNCM220-CD?
HR is the default condition — default stock condition for carburizing-grade bar that will be machined and then case hardened. CD: pick for straight, size-accurate bright bar for automatic screw-machine work before carburizing. Yield strength is 385 MPa in HR versus 570 MPa in CD.
How much does SNCM220 cost?
SNCM220 is a standard-cost steel ($$), cheaper than about 71% 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 SNCM220?
Yes — SNCM220 is available for CNC machining and sheet metal; 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 4053 — Low-alloyed structural steels for machine structural use — JSA (2016)
- GB/T 3077 — Alloy structural steels (20CrNiMo) — SAC (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys (SAE 8620) — ASM International (1990)
- ASM Machining Data Handbook — ASM International (1980)
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
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.