Steel SNCM240 Normalized
Heat-treated state
JIS SNCM240
Choose normalising at about 870 °C with air cooling to refine grain and homogenise structure in forgings and rough blanks before quench and temper; 690 MPa yield at 269 HB.
Values for the Normalized condition
Other SNCM240 tempers and conditions
SNCM240 is listed in 10 conditions; see the grade overview at SNCM240.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full anneal, ~815 °C furnace cool | Pick the softest state, fully annealed at about 815 °C with furnace cooling to 187 HB, for rough turning, deep-hole drilling or as an intermediate step before cold forming. | 425 | 700 | 26 | 187 HB | — |
Hot rolled | Choose this untreated as-rolled or as-forged bar (550 MPa yield, 850 MPa tensile, 240 HB) as low-cost stock when you will anneal or quench and temper it yourself. | 550 | 850 | 20 | 22 HRC | 8 % IACS |
NormalizedThis page ~870 °C, air cool | Choose normalising at about 870 °C with air cooling to refine grain and homogenise structure in forgings and rough blanks before quench and temper; 690 MPa yield at 269 HB. | 690 | 930 | 22 | 27 HRC | — |
Cold drawn | Pick annealed-then-cold-drawn small-diameter bar for tight dimensional tolerance and bright surface with direct machining, trading elongation down to 12% for 700 MPa yield. | 700 | 830 | 12 | 22 HRC | 7.8 % IACS |
Q&T to 24–28 HRC | Choose this soft quench-and-temper step, tempered around 620 °C to 24–28 HRC, for large-section shafts, flanges and die shoes where 20% elongation and toughness outrank strength. | 740 | 880 | 20 | 26 HRC | — |
QTDefault Quenched and tempered | Use the standard delivery state, oil quenched near 830 °C and tempered to 255–311 HB, for shafts, gear blanks and connecting rods needing 820 MPa yield with 17% elongation. | 820 | 1,000 | 17 | 30 HRC | — |
Induction hardened | Specify a quenched-and-tempered core with an induction-hardened 52–58 HRC case for journals, splines and tooth flanks needing wear resistance over a tough core; finish machine before hardening. | 820 | 1,000 | 15 | 55 HRC | 7.5 % IACS |
Q&T to 28–32 HRC | Pick the 28–32 HRC temper (about 590 °C) as the general-purpose machine-and-use hardness, balancing 850 MPa yield against still-workable cutting behaviour. | 850 | 1,000 | 17 | 30 HRC | 7.8 % IACS |
Q&T to 32–36 HRC | Use tempering near 540 °C to 32–36 HRC for highly loaded shafts, bolts and gear blanks; yield rises to 1000 MPa but cutting resistance increases markedly. | 1,000 | 1,120 | 15 | 34 HRC | — |
Q&T to 38–42 HRC | Choose the 450 °C temper to 38–42 HRC only for small sections such as pins, fasteners and tooling; 1190 MPa yield comes with 12% elongation and poor weldability. | 1,190 | 1,310 | 12 | 40 HRC | — |
What is SNCM240 Normalized?
SNCM240 Normalized is SNCM240 heat treated to Normalized — choose normalising at about 870 °C with air cooling to refine grain and homogenise structure in forgings and rough blanks before quench and temper; 690 MPa yield at 269 HB. SNCM240 Normalized has a yield strength of 690 MPa (100 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 80% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi). SNCM240 Normalized 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). QT is the default condition FabDigit quotes; Normalized is available on request or by drawing note.
Advantages
- High strength — 690 MPa (100 ksi), better than 80% of steel grades
SNCM240 Normalized properties
Typical room-temperature values for SNCM240 Normalized; 10 are specific to this condition. Other listed values are SNCM240 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SNCM240 Normalized 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
SNCM240 Normalized has a yield strength of 690 MPa (100 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 80% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SNCM240 Normalized is rated for continuous service to 400°C (752 °F). It conducts heat at 43 W/m·K (24.8 BTU/hr·ft·°F), better than 51% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
SNCM240 Normalized conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of SNCM240 Normalized takes about 29 MJ of energy and emits 2.3 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 25%.
Manufacturability8
SNCM240 Normalized's machinability is fair (52/100, better than 52% of steel grades); weldability fair (35/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SNCM240 Normalized
Is SNCM240 easy to machine?
Annealed or quenched-and-tempered material up to about 32 HRC machines efficiently with carbide tooling (roughly 55-65% of AISI 1212). Above 36 HRC switch to CBN or ceramic hard turning, or finish by grinding.
Can SNCM240 be welded?
Carbon equivalent is high (Ceq ≈ 0.75), so welding requires 200-300 °C preheat, low-hydrogen consumables and a post-weld temper. Welding quenched-and-tempered parts degrades heat-affected-zone properties.
Can SNCM240 be formed, bent or molded?
Forge at 1050-1200 °C, finishing no lower than 850 °C, then slow cool or normalize. Cold forming is limited to light bending and upsetting in the annealed condition.
What surface finishes work on SNCM240?
Cannot be anodized; use black oxide, phosphate, zinc or hard chrome plating, or paint for corrosion protection. High-strength parts must be baked at 190 °C or above after plating to remove hydrogen; induction-hardened surfaces can be ground and polished.
SNCM240 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 G 4103 | 0.38 – 0.43 | 0.4 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.7 – 1 | 0.85 |
| 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 | — |
SNCM240 Normalized — frequently asked
What is SNCM240 Normalized used for?
SNCM240 Normalized is typically used for carburized gears, shafts and gearbox components. In short: case-hardening Ni-Cr-Mo steel; stronger core than SNCM220; medium-duty carburized gears.
What is the yield strength of SNCM240 Normalized?
SNCM240 Normalized has a typical yield strength of 690 MPa (100 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 80% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is SNCM240 Normalized easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Annealed or quenched-and-tempered material up to about 32 HRC machines efficiently with carbide tooling (roughly 55-65% of AISI 1212). Above 36 HRC switch to CBN or ceramic hard turning, or finish by grinding.
Can SNCM240 Normalized be welded?
With care — weldability is rated fair (35/100). Carbon equivalent is high (Ceq ≈ 0.75), so welding requires 200-300 °C preheat, low-hydrogen consumables and a post-weld temper. Welding quenched-and-tempered parts degrades heat-affected-zone properties.
What surface finishes work on SNCM240 Normalized?
Cannot be anodized; use black oxide, phosphate, zinc or hard chrome plating, or paint for corrosion protection. High-strength parts must be baked at 190 °C or above after plating to remove hydrogen; induction-hardened surfaces can be ground and polished.
Can SNCM240 Normalized be formed, bent or molded?
Forge at 1050-1200 °C, finishing no lower than 850 °C, then slow cool or normalize. Cold forming is limited to light bending and upsetting in the annealed condition.
What is the maximum service temperature of SNCM240 Normalized?
SNCM240 Normalized 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 SNCM240-QT and SNCM240-HR?
QT is the default condition — use the standard delivery state, oil quenched near 830 °C and tempered to 255–311 HB, for shafts, gear blanks and connecting rods needing 820 MPa yield with 17% elongation. HR: choose this untreated as-rolled or as-forged bar (550 MPa yield, 850 MPa tensile, 240 HB) as low-cost stock when you will anneal or quench and temper it yourself. Yield strength is 820 MPa in QT versus 550 MPa in HR.
Sources
- JIS G 4103 Nickel-chromium-molybdenum steels — JSA (2021)
- SAE J404 Chemical Compositions of SAE Alloy Steels (8640) — SAE International (2021)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4: Heat Treating — ASM International (1991)
- ASM Handbook Vol.19: Fatigue and Fracture — ASM International (1996)
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.