Steel 41NiCrMo7-3-2 +QT250 (+QT)
Heat-treated state
EN 41NiCrMo7-3-2
Largest Q&T class certified by EN 10083-3 for very heavy rotor/shaft forgings.
Values for the +QT250 condition
Other 41NiCrMo7-3-2 tempers and conditions
41NiCrMo7-3-2 is listed in 12 conditions; see the grade overview at 41NiCrMo7-3-2.
Compare all 12 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Pick for cold extrusion, cold heading of bolts, or when maximum machinability/lowest hardness is required. | 420 | 700 | 21 | 200 HB | 44 W/m·K |
Annealed | Softest general-purpose stock condition for heavy machining before quench and temper. | 450 | 760 | 19 | 220 HB | 44 W/m·K |
Treated for shearability | Softened bar so it can be cold-sheared to billet length before forging. | 480 | 800 | 17 | 21 HRC | 8.1 % IACS |
Hot rolled | Cheapest mill condition; buy when you will heat-treat the part yourself after rough machining. | 520 | 880 | 15 | 25 HRC | 8 % IACS |
Normalized | Grain-refined forging condition; used when uniform structure is wanted before final hardening. | 600 | 950 | 14 | 28 HRC | — |
+QT250This page +QT | Largest Q&T class certified by EN 10083-3 for very heavy rotor/shaft forgings. | 650 | 875 | 15 | 26 HRC | — |
+QT | Heavy-section forgings where core toughness matters more than peak strength. | 750 | 1,000 | 14 | 31 HRC | — |
Cold drawn | Cold-drawn from the annealed condition for close tolerance and bright surface on small-diameter bar. | 800 | 950 | 8 | 30 HRC | 7.7 % IACS |
+QT100Default +QT | The condition most commonly stocked and specified for heavily loaded forged shafts and gears. | 850 | 1,100 | 13 | 35 HRC | — |
+QT | Standard high-strength class for medium shafts, gear blanks and connecting rods. | 950 | 1,200 | 11 | 39 HRC | — |
+QT | Highest-strength Q&T class for small bar, bolts and pins where notch sensitivity is manageable. | 1,050 | 1,320 | 10 | 42 HRC | — |
Hardenability-guaranteed (Jominy band) / hardened, as-quenched | Order +H when the Jominy hardenability band must be certified for deep-hardening forgings; the as-quenched martensite shown here must always be tempered before service. | 1,500 | 1,950 | 4 | 55 HRC | — |
What is 41NiCrMo7-3-2 +QT250?
41NiCrMo7-3-2 +QT250 is 41NiCrMo7-3-2 heat treated to +QT250 — largest Q&T class certified by EN 10083-3 for very heavy rotor/shaft forgings. 41NiCrMo7-3-2 +QT250 has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 875 MPa (127 ksi) — stronger than 79% of steel grades. Elongation at break is 15% and the elastic modulus is 205 GPa (29.7 Msi). 41NiCrMo7-3-2 +QT250 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). +QT100 is the default condition FabDigit quotes; +QT250 is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- High strength — 650 MPa (94.3 ksi), better than 79% of steel grades
Limitations
- Limited formability — 22/100, worse than 76% of steel grades
41NiCrMo7-3-2 +QT250 properties
Typical room-temperature values for 41NiCrMo7-3-2 +QT250; 13 are specific to this condition. Other listed values are 41NiCrMo7-3-2 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
41NiCrMo7-3-2 +QT250 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
41NiCrMo7-3-2 +QT250 has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 875 MPa (127 ksi) — stronger than 79% of steel grades. Elongation at break is 15% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
41NiCrMo7-3-2 +QT250 is rated for continuous service to 425°C (797 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
41NiCrMo7-3-2 +QT250 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 41NiCrMo7-3-2 +QT250 takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability6
41NiCrMo7-3-2 +QT250's machinability is fair (48/100, worse than 57% of steel grades); weldability poor (30/100); formability poor (22/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 41NiCrMo7-3-2 +QT250
Is 41NiCrMo7-3-2 easy to machine?
Rough machine in +A/+AC (≈55 % of AISI 1212), finish after Q&T with rigid setups, carbide or CBN and reduced speeds above 340 HB; grind or hard-turn above 45 HRC.
Can 41NiCrMo7-3-2 be welded?
Poor as-welded (CE ≈ 0.8–0.9): use low-hydrogen consumables, 250–350 °C preheat/interpass and immediate temper/PWHT at 550–650 °C to avoid cold cracking.
Can 41NiCrMo7-3-2 be formed, bent or molded?
Hot forge 1100–1200 °C, finish above 850 °C, then normalize; cold forming only in the spheroidized +AC condition.
What surface finishes work on 41NiCrMo7-3-2?
Takes hard chrome, zinc/phosphate and nitriding well; bake 190–220 °C for 4–24 h after electroplating to relieve hydrogen; polishes to a bright finish but must be painted or plated for corrosion protection.
41NiCrMo7-3-2 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 | 0.38 – 0.43 | 0.41 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | — |
| Slower S grades available for cleanliness | ≤ 0.04 | — |
| Cr | 0.7 – 0.9 | 0.8 |
| Mo | 0.2 – 0.3 | 0.25 |
| Ni | 1.65 – 2 | 1.8 |
| Fe | balance | — |
41NiCrMo7-3-2 +QT250 — frequently asked
What is 41NiCrMo7-3-2 +QT250 used for?
41NiCrMo7-3-2 +QT250 is typically used for heavy-duty shafts, gears and aerospace/industrial forgings. In short: highest core strength here; through-hardens thick sections; poor as-welded weldability.
What is the yield strength of 41NiCrMo7-3-2 +QT250?
41NiCrMo7-3-2 +QT250 has a typical yield strength of 650 MPa (94.3 ksi) and a tensile strength of 875 MPa (127 ksi) — stronger than 79% of steel grades. Strength varies by condition: see the 12 listed tempers.
Is 41NiCrMo7-3-2 +QT250 easy to machine?
Reasonably — machinability is rated fair (48/100, worse than 57% of steel grades). Rough machine in +A/+AC (≈55 % of AISI 1212), finish after Q&T with rigid setups, carbide or CBN and reduced speeds above 340 HB; grind or hard-turn above 45 HRC.
Can 41NiCrMo7-3-2 +QT250 be welded?
Not readily — weldability is rated poor (30/100). Poor as-welded (CE ≈ 0.8–0.9): use low-hydrogen consumables, 250–350 °C preheat/interpass and immediate temper/PWHT at 550–650 °C to avoid cold cracking.
What surface finishes work on 41NiCrMo7-3-2 +QT250?
Takes hard chrome, zinc/phosphate and nitriding well; bake 190–220 °C for 4–24 h after electroplating to relieve hydrogen; polishes to a bright finish but must be painted or plated for corrosion protection.
Can 41NiCrMo7-3-2 +QT250 be formed, bent or molded?
Hot forge 1100–1200 °C, finish above 850 °C, then normalize; cold forming only in the spheroidized +AC condition.
What is the maximum service temperature of 41NiCrMo7-3-2 +QT250?
41NiCrMo7-3-2 +QT250 is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10083-3 Steels for quenching and tempering — Part 3: Alloy steels — CEN (2006)
- EN 10277 Bright steel products — technical delivery conditions — CEN (2018)
- GB/T 3077 (40CrNiMoA) — SAC (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys (AISI 4340) — ASM International (1990)
- MMPDS-17 (4340 steel design allowables) — Battelle/FAA (2022)
- Machinery's Handbook, 31st ed. — machinability ratings — Industrial Press (2020)
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.