Steel SNCM220 · supply condition · default condition
Steel SNCM220-HR
Properties of the HR condition, compared with the other SNCM220 tempers.
Default stock condition for carburizing-grade bar that will be machined and then case hardened.
What is SNCM220-HR?
SNCM220-HR is SNCM220 supplied in the HR condition — default stock condition for carburizing-grade bar that will be machined and then case hardened. SNCM220-HR 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). SNCM220-HR 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).
Advantages
- Ductile — tolerates forming and impact — 29%, better than 91% of steel grades
SNCM220-HR properties
Typical room-temperature values for SNCM220-HR — 9 properties are specific to this condition; the rest are grade-level values shared by every SNCM220 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
SNCM220-HR 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).
Mechanical14
SNCM220-HR 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-HR 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-HR conducts electricity at 8.5 % IACS, better than 62% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of SNCM220-HR takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 55% of steel grades. Typical recycled content is 30%.
Manufacturability7
SNCM220-HR'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.
Other SNCM220 tempers and conditions
SNCM220 is also supplied in 6 other conditions. The full side-by-side table is on the SNCM220 overview.
- HRDefaultDefault stock condition for carburizing-grade bar that will be machined and then case hardened.385 MPa yield · 160 HB
- CarburizedThe intended service condition: gas-carburized 0.5–1.5 mm case for gear-tooth wear and contact-fatigue resistance with a tough core.800 MPa yield · 60 HRC
- Q&TDirect-hardened condition for shafts and fasteners used without carburizing, or as specified core strength after case hardening.720 MPa yield · 29 HRC
- CDPick for straight, size-accurate bright bar for automatic screw-machine work before carburizing.570 MPa yield · 200 HB
- AnnealedUse when maximum softness and machinability or cold forming (cold heading, deep boring) is required before carburizing.385 MPa yield · 149 HB
- NormalizedStandard pre-treatment to refine grain and homogenize structure for uniform case depth and low carburizing distortion.360 MPa yield · 183 HB
Working with SNCM220-HR
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.
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.
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 | — |
SNCM220-HR — frequently asked
What is SNCM220-HR used for?
SNCM220-HR is typically used for gears, industrial drive shafts and pins. In short: carburizing Ni-Cr-Mo bar.
What is the yield strength of SNCM220-HR?
SNCM220-HR 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-HR 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-HR 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-HR?
Requires protection — black oxide, phosphate, zinc or oil after carburizing; ground case surfaces polish well but corrode quickly if left bare.
Can SNCM220-HR 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-HR?
SNCM220-HR 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.
Can FabDigit make parts in SNCM220-HR?
Yes — SNCM220-HR is available for CNC machining and sheet metal with instant online pricing. 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.