Steel SCM440-IH (Induction hardened)
Heat-treated state
JIS SCM440 · EN 42CrMo4
For journals, splines and guideways needing a wear-resistant 52–58 HRC case over a tough Q&T core.
Values for the IH condition
Other SCM440 tempers and conditions
SCM440 is listed in 11 conditions; see the grade overview at SCM440.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full/spheroidize annealed, softest condition | Choose for heavy machining, cold forming or deep-hole drilling before final hardening. | 415 | 655 | 25 | 197 HB | — |
Cold rolled | Thin strip/sheet stock with tight thickness and a clean surface, for stamped parts later hardened. | 550 | 750 | 13 | 17 HRC | 7.8 % IACS |
HRDefault Hot rolled | Cheapest stock form for parts that will be machined then heat treated by the fabricator. | 590 | 880 | 17 | 25 HRC | — |
860–880 °C air cooled | Uniform fine grain and mid-range strength; used as pre-treatment before machining/hardening or as final state for low-stress parts. | 655 | 1,020 | 17.5 | 32 HRC | — |
Quenched and high-temperature tempered | Maximum toughness / NACE-friendly hardness cap for pressure and downhole components. | 720 | 860 | 20 | 24 HRC | — |
Cold drawn | Pick for near-net-size shafts and turned parts needing good surface finish and straightness without further grinding. | 750 | 900 | 12 | 26 HRC | — |
Q&T then gas/plasma nitrided (500–540 °C) | Low-distortion hard case (~0.2–0.5 mm, 550–650 HV) for wear and fatigue-critical shafts and screws. | 850 | 980 | 12 | 55 HRC | 7.8 % IACS |
Quenched and tempered | Standard supply condition for shafts, gears and machine parts needing balanced strength and toughness. | 880 | 1,000 | 16 | 30 HRC | — |
IHThis page Induction hardened | For journals, splines and guideways needing a wear-resistant 52–58 HRC case over a tough Q&T core. | 880 | 1,000 | 14 | 55 HRC | 7.8 % IACS |
Quenched and medium-temperature tempered | Higher-strength shafts, high-tensile bolting and moulds where toughness is still needed. | 1,060 | 1,180 | 14 | 36 HRC | — |
Quenched and low-temperature tempered | Highest strength/wear condition for pins, dies and rams; accept low impact toughness and hydrogen-embrittlement risk when plating. | 1,280 | 1,400 | 11 | 42 HRC | — |
What is SCM440-IH?
SCM440-IH is SCM440 heat treated to IH — for journals, splines and guideways needing a wear-resistant 52–58 HRC case over a tough Q&T core. SCM440-IH has a yield strength of 880 MPa (128 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 89% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi). SCM440-IH has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F). HR is the default condition FabDigit quotes; IH is available on request or by drawing note.
Advantages
- High strength — 880 MPa (128 ksi), better than 89% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited formability — 5/100, worse than 99% of steel grades
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Difficult to machine — 20/100, worse than 97% of steel grades
- Difficult to weld — 15/100, worse than 91% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
SCM440-IH properties
Typical room-temperature values for SCM440-IH; 22 are specific to this condition. Other listed values are SCM440 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SCM440-IH has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F).
Mechanical16
SCM440-IH has a yield strength of 880 MPa (128 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 89% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
SCM440-IH is rated for continuous service to 180°C (356 °F). It conducts heat at 42.6 W/m·K (24.6 BTU/hr·ft·°F), worse than 51% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
SCM440-IH 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 SCM440-IH takes about 29 MJ of energy and emits 2.1 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 30%.
Manufacturability6
SCM440-IH's machinability is poor (20/100, worse than 97% of steel grades); weldability poor (15/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SCM440-IH
Is SCM440 easy to machine?
Machines best at 200–280 HB with coated carbide, ~120–180 m/min turning; above 40 HRC switch to CBN/ceramic or grind.
Can SCM440 be welded?
Weldable with low-hydrogen consumables but requires 250–350 °C preheat, interpass control and immediate PWHT/temper at 600–650 °C to avoid HAZ cracking.
Can SCM440 be formed, bent or molded?
Hot forge at 1100–1200 °C then normalize; cold bending only in the annealed condition with generous radii (≥3t).
What surface finishes work on SCM440?
Not corrosion resistant — use black oxide, phosphate, Zn or Zn-Ni plating, or nitriding; bake 190–220 °C for 4 h after plating parts above ~35 HRC to relieve hydrogen.
SCM440 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 G4053 SCM440 | 0.38 – 0.43 | 0.4 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Cr | 0.9 – 1.2 | 1.05 |
| Mo | 0.15 – 0.3 | 0.22 |
| Niresidual, max | ≤ 0.25 | — |
| Curesidual, max | ≤ 0.3 | — |
| Fe | balance | — |
SCM440-IH — frequently asked
What is SCM440-IH used for?
SCM440-IH is typically used for drive shafts, crankshafts and industrial bolts. In short: workhorse Cr-Mo Japanese bar.
What is the yield strength of SCM440-IH?
SCM440-IH has a typical yield strength of 880 MPa (128 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 89% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is SCM440-IH easy to machine?
Not especially — machinability is rated poor (20/100, worse than 97% of steel grades). Machines best at 200–280 HB with coated carbide, ~120–180 m/min turning; above 40 HRC switch to CBN/ceramic or grind.
Can SCM440-IH be welded?
Not readily — weldability is rated poor (15/100). Weldable with low-hydrogen consumables but requires 250–350 °C preheat, interpass control and immediate PWHT/temper at 600–650 °C to avoid HAZ cracking.
What surface finishes work on SCM440-IH?
Not corrosion resistant — use black oxide, phosphate, Zn or Zn-Ni plating, or nitriding; bake 190–220 °C for 4 h after plating parts above ~35 HRC to relieve hydrogen.
Can SCM440-IH be formed, bent or molded?
Hot forge at 1100–1200 °C then normalize; cold bending only in the annealed condition with generous radii (≥3t).
What is the maximum service temperature of SCM440-IH?
SCM440-IH is rated for continuous use to about 180°C (356 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SCM440-HR and SCM440-IH?
HR is the default condition — cheapest stock form for parts that will be machined then heat treated by the fabricator. IH: for journals, splines and guideways needing a wear-resistant 52–58 HRC case over a tough Q&T core. Yield strength is 590 MPa in HR versus 880 MPa in IH.
Can FabDigit make parts in SCM440-IH?
Yes — SCM440-IH 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 (42CrMo) — SAC (2015)
- ASTM A29/A29M & A322 (AISI 4140) — ASTM (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- 42CrMo4 / 4140 heat-treatable steel datasheet — Böhler / Ovako (2022)
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.