Steel 40NCD3
EN 40NCD3
40NCD3 is a French AFNOR nickel-chromium-molybdenum quenched-and-tempered engineering steel, cross-referenced to 4340, stocked annealed (+A), normalized (+N), hot rolled, cold drawn (+C), in hardness bands from QT22-26 to QT36-40 HRC, and in induction-hardened or nitrided conditions.
Reference datasheet — 40NCD3 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the QT28-32 condition
40NCD3 tempers and conditions
40NCD3 is supplied in 10 conditions, soft to hard. QT28-32 is the default FabDigit quotes; the values on this page are for it.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Choose for deep machining, cold sawing or before customer heat treatment; max ~241 HB per EN 10083-3. | 450 | 700 | 20 | 210 HB | — |
Hot rolled | Cheapest mill condition for stock that will be fully heat treated after rough machining. | 480 | 780 | 17 | 22 HRC | 7.8 % IACS |
Normalized | Uniform fine-grain structure for forgings before final Q&T, or for moderately stressed parts. | 520 | 830 | 18 | 24 HRC | — |
Cold drawn | Pick for close-tolerance small-diameter bar used as-supplied without further heat treatment. | 620 | 800 | 12 | 22 HRC | 7.8 % IACS |
+QT 22–26 HRC | Use for heavy sections (>100 mm), maximum toughness, or where NACE MR0175 caps hardness at 22 HRC. | 640 | 870 | 16 | 24 HRC | — |
Nitrided | Choose when a hard, low-distortion wear/fatigue skin is needed on an already tempered part (temper ≥ 570 °C required). | 780 | 980 | 12 | 55 HRC | 7.8 % IACS |
QT28-32Default +QT 28–32 HRC | The standard stock condition: best strength/toughness/machinability balance for shafts, connecting rods and forgings. | 800 | 1,000 | 14 | 31 HRC | — |
Induction hardened | Use for journal/bearing surfaces needing 52–58 HRC wear resistance over a tough ~300 HB core. | 800 | 1,000 | 13 | 55 HRC | 7.5 % IACS |
+QT 32–36 HRC | Pick for higher-loaded shafts, gear blanks and mould bases where some machining is still needed. | 950 | 1,150 | 12 | 34 HRC | — |
+QT 36–40 HRC | Highest practical Q&T level for this lean Ni-Cr-Mo grade in thin sections; toughness and machinability drop noticeably. | 1,100 | 1,300 | 10 | 38 HRC | — |
What is 40NCD3?
40NCD3 is a French AFNOR nickel-chromium-molybdenum quenched-and-tempered engineering steel, cross-referenced to 4340, stocked annealed (+A), normalized (+N), hot rolled, cold drawn (+C), in hardness bands from QT22-26 to QT36-40 HRC, and in induction-hardened or nitrided conditions. It suits medium-to-high strength shafts, gears and structural forgings in bar and forged form. Default values are 800 MPa yield, 1000 MPa tensile, 14 % elongation, 300 HB (31 HRC), service to 400 °C and a machinability score of 50. It has no inherent corrosion resistance and needs preheat and post-weld temper; 42CD4 is the common alternative when higher strength at size is wanted. 40NCD3 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). 40NCD3 has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
What is 40NCD3 used for?
- shafts
- gears
- structural forgings
Advantages
- High strength — 800 MPa (116 ksi), better than 86% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited ductility — 14%, worse than 75% of steel grades
40NCD3 properties
Typical room-temperature values for 40NCD3-QT28-32; bars are the position among steel grades.
Physical3
40NCD3 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
40NCD3 has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
40NCD3 is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
40NCD3 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 40NCD3 takes about 30 MJ of energy and emits 2.1 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability6
40NCD3's machinability is fair (50/100, worse than 53% of steel grades); weldability fair (35/100); formability poor (30/100).
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. 40NCD3 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 40NCD3
Is 40NCD3 easy to machine?
Machine in the annealed or ≤32 HRC condition with coated carbide, 80–140 m/min and rigid setups; above 36 HRC switch to CBN/ceramic or grind.
Can 40NCD3 be welded?
Weldable with low-hydrogen consumables but requires 200–300 °C preheat, controlled interpass and 550–650 °C post-weld temper; welding above 32 HRC risks HAZ cracking.
Can 40NCD3 be formed, bent or molded?
Hot forge 1100–1200 °C, finish above 850 °C, then normalize; cold forming limited to mild bending in the annealed condition.
40NCD3 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 |
|---|---|---|
| CAFNOR 40NCD3 / EN 40NiCrMo2-2 (1.6546) | 0.36 – 0.44 | 0.4 |
| Si | 0.1 – 0.4 | 0.25 |
| Mn | 0.5 – 0.9 | 0.7 |
| NiAFNOR digit 3 ≈ Ni 0.75 % | 0.4 – 0.9 | 0.75 |
| Cr | 0.35 – 0.7 | 0.5 |
| Mo | 0.15 – 0.3 | 0.2 |
| P | ≤ 0.04 | 0.02 |
| S0.020–0.040 for free-machining +S versions | ≤ 0.04 | 0.02 |
| Fe | balance |
What surface finishes work on 40NCD3?
No natural corrosion protection — use phosphating + oil, black oxide, zinc or hard-chrome plating (bake at 190 °C to avoid hydrogen embrittlement); polishes well to mirror finish for mould applications.
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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 40NCD3 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 4340
How much does 40NCD3 cost?
40NCD3 is a budget-cost steel ($), cheaper than about 90% 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.
40NCD3 — frequently asked
What is 40NCD3 used for?
40NCD3 is typically used for shafts, gears and structural forgings. In short: pre-hard shaft steel; nitrides and induction hardens; weldable with preheat.
What is the yield strength of 40NCD3?
40NCD3 has a typical yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 40NCD3 easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machine in the annealed or ≤32 HRC condition with coated carbide, 80–140 m/min and rigid setups; above 36 HRC switch to CBN/ceramic or grind.
Can 40NCD3 be welded?
With care — weldability is rated fair (35/100). Weldable with low-hydrogen consumables but requires 200–300 °C preheat, controlled interpass and 550–650 °C post-weld temper; welding above 32 HRC risks HAZ cracking.
What surface finishes work on 40NCD3?
No natural corrosion protection — use phosphating + oil, black oxide, zinc or hard-chrome plating (bake at 190 °C to avoid hydrogen embrittlement); polishes well to mirror finish for mould applications.
Can 40NCD3 be formed, bent or molded?
Hot forge 1100–1200 °C, finish above 850 °C, then normalize; cold forming limited to mild bending in the annealed condition.
What is the maximum service temperature of 40NCD3?
40NCD3 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 40NCD3 QT28-32 and 40NCD3-HR?
QT28-32 is the default condition — the standard stock condition: best strength/toughness/machinability balance for shafts, connecting rods and forgings. HR: cheapest mill condition for stock that will be fully heat treated after rough machining. Yield strength is 800 MPa in QT28-32 versus 480 MPa in HR.
How much does 40NCD3 cost?
40NCD3 is a budget-cost steel ($), cheaper than about 90% 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.
Sources
- EN 10083-3 Steels for quenching and tempering – 40NiCrMo2-2 (1.6546) — CEN (2006)
- NF A35-552 / AFNOR alloy structural steels (40NCD3) — AFNOR (1993)
- GB/T 3077 (40CrNiMoA) — SAC (2015)
- ASM Handbook Vol.1 – Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 – Fatigue and Fracture — ASM International (1996)
- Q&T engineering steel bar datasheets (40NiCrMo2-2 / 4340 class) — Ovako / Böhler (2022)
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.