Steel 40CrNiMoA · hardness band
Steel 40CrNiMoA Q&T 48-52 HRC
Properties of the Q&T 48-52 HRC condition, compared with the other 40CrNiMoA tempers.
Maximum strength (~1800 MPa) condition for wear parts and tooling; brittle, notch- and hydrogen-sensitive, so avoid stress concentrations and plate only with post-bake.
What is 40CrNiMoA Q&T 48-52 HRC?
40CrNiMoA Q&T 48-52 HRC is 40CrNiMoA heat treated to Q&T 48-52 HRC — maximum strength (~1800 MPa) condition for wear parts and tooling; brittle, notch- and hydrogen-sensitive, so avoid stress concentrations and plate only with post-bake. 40CrNiMoA Q&T 48-52 HRC has a yield strength of 1,600 MPa (232 ksi) and a tensile strength of 1,800 MPa (261 ksi) — stronger than 98% of steel grades. Elongation at break is 8% and the elastic modulus is 207 GPa (30 Msi). 40CrNiMoA Q&T 48-52 HRC 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). Q&T is the default condition FabDigit quotes; Q&T 48-52 HRC is available on request or by drawing note.
Advantages
- High strength — 1,600 MPa (232 ksi), better than 98% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Difficult to machine — 12/100, worse than 99% of steel grades
- Limited ductility — 8%, worse than 95% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Low fracture toughness — 50 MPa·√m (45.5 ksi·√in), worse than 87% of steel grades
40CrNiMoA Q&T 48-52 HRC properties
Typical room-temperature values for 40CrNiMoA Q&T 48-52 HRC — 12 properties are specific to this condition; the rest are grade-level values shared by every 40CrNiMoA temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
40CrNiMoA Q&T 48-52 HRC 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
40CrNiMoA Q&T 48-52 HRC has a yield strength of 1,600 MPa (232 ksi) and a tensile strength of 1,800 MPa (261 ksi) — stronger than 98% of steel grades. Elongation at break is 8% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
40CrNiMoA Q&T 48-52 HRC is rated for continuous service to 200°C (392 °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
40CrNiMoA Q&T 48-52 HRC conducts electricity at 7 % IACS, worse than 74% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of 40CrNiMoA Q&T 48-52 HRC takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability8
40CrNiMoA Q&T 48-52 HRC's machinability is not recommended (12/100, worse than 99% of steel grades); weldability poor (30/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 40CrNiMoA tempers and conditions
40CrNiMoA is also supplied in 9 other conditions. The full side-by-side table is on the 40CrNiMoA overview.
- Q&TDefaultStandard stocked condition: balanced ~1000–1100 MPa strength with high toughness for shafts, gears and high-strength fasteners.950 MPa yield · 34 HRC
- Q&T 48-52 HRCMaximum strength (~1800 MPa) condition for wear parts and tooling; brittle, notch- and hydrogen-sensitive, so avoid stress concentrations and plate only with post-bake.1,600 MPa yield · 50 HRC
- Q&T 42-46 HRCHigh-strength ~1500 MPa condition for torsion bars, landing-gear-type parts and tooling; toughness and machinability drop sharply.1,350 MPa yield · 44 HRC
- Q&T 38-42 HRCUse for higher-strength ~1300 MPa parts such as aerospace fittings and heavy-duty bolts where some ductility is still needed.1,200 MPa yield · 40 HRC
- Q&T 32-36 HRCMost common ordered hardness band for gears, connecting rods and driveline shafts; good strength/toughness compromise.1,000 MPa yield · 34 HRC
- NormalizedUniform, refined structure for forgings before final Q&T; already strong but with limited ductility because of the air-hardened bainite/martensite.860 MPa yield · 39 HRC
- Q&T 28-32 HRCPick when toughness and machinability matter more than strength, e.g. large forged shafts and pressure-containing parts.860 MPa yield · 30 HRC
- CDBright, close-tolerance bar for direct machining of moderately loaded parts without further heat treatment.720 MPa yield · 250 HB
- AnnealedSoftest condition for deep machining, cold forming or as a pre-heat-treat stock; hardness capped at 269 HB per GB/T 3077.470 MPa yield · 217 HB
Working with 40CrNiMoA Q&T 48-52 HRC
Is 40CrNiMoA easy to machine?
Machine in the annealed or ≤32 HRC condition with rigid setups, sharp carbide and generous coolant; above 40 HRC switch to CBN/ceramic turning or grinding, and rough before final temper where possible.
Can 40CrNiMoA be welded?
High carbon equivalent means preheat 250–350 °C, low-hydrogen filler (e.g. ER100S/ER110S or matching), interpass control and immediate PWHT/re-temper; avoid welding parts already at high hardness.
Can 40CrNiMoA be formed, bent or molded?
Hot forge 1100–1200 °C, finish above 900 °C and normalize afterwards; cold forming is limited to the annealed condition and mild bends only.
What surface finishes work on 40CrNiMoA?
Not anodizable — protect with black oxide, phosphate + oil, Zn or Cd plating, hard chrome, or gas nitriding (surface 550–650 HV); bake 190–220 °C after electroplating high-hardness parts to relieve hydrogen.
40CrNiMoA 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 | 0.37 – 0.44 | 0.4 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.5 – 0.8 | 0.65 |
| Cr | 0.6 – 0.9 | 0.75 |
| Ni | 1.25 – 1.65 | 1.45 |
| Mo | 0.15 – 0.25 | 0.2 |
| PA grade (high-quality) limit | ≤ 0.03 | — |
| SA grade (high-quality) limit | ≤ 0.03 | — |
| Curesidual | ≤ 0.3 | — |
| Fe | balance | — |
40CrNiMoA Q&T 48-52 HRC — frequently asked
What is 40CrNiMoA Q&T 48-52 HRC used for?
40CrNiMoA Q&T 48-52 HRC is typically used for aircraft landing gear components, drive shafts, industrial axles, gearbox shafts and pinions, heavy-duty crankshafts and high-strength bolts and studs. In short: premium Ni-Cr-Mo bar.
What is the yield strength of 40CrNiMoA Q&T 48-52 HRC?
40CrNiMoA Q&T 48-52 HRC has a typical yield strength of 1,600 MPa (232 ksi) and a tensile strength of 1,800 MPa (261 ksi) — stronger than 98% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 40CrNiMoA Q&T 48-52 HRC easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Machine in the annealed or ≤32 HRC condition with rigid setups, sharp carbide and generous coolant; above 40 HRC switch to CBN/ceramic turning or grinding, and rough before final temper where possible.
Can 40CrNiMoA Q&T 48-52 HRC be welded?
Not readily — weldability is rated poor (30/100). High carbon equivalent means preheat 250–350 °C, low-hydrogen filler (e.g. ER100S/ER110S or matching), interpass control and immediate PWHT/re-temper; avoid welding parts already at high hardness.
What surface finishes work on 40CrNiMoA Q&T 48-52 HRC?
Not anodizable — protect with black oxide, phosphate + oil, Zn or Cd plating, hard chrome, or gas nitriding (surface 550–650 HV); bake 190–220 °C after electroplating high-hardness parts to relieve hydrogen.
Can 40CrNiMoA Q&T 48-52 HRC be formed, bent or molded?
Hot forge 1100–1200 °C, finish above 900 °C and normalize afterwards; cold forming is limited to the annealed condition and mild bends only.
What is the maximum service temperature of 40CrNiMoA Q&T 48-52 HRC?
40CrNiMoA Q&T 48-52 HRC is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 40CrNiMoA Q&T and 40CrNiMoA-HR?
Q&T is the default condition — standard stocked condition: balanced ~1000–1100 MPa strength with high toughness for shafts, gears and high-strength fasteners. HR: cheapest mill condition, bought as forging or machining blank when the shop will heat treat afterwards; properties vary with section and cooling rate. Yield strength is 950 MPa in Q&T versus 620 MPa in HR.
Can FabDigit make parts in 40CrNiMoA Q&T 48-52 HRC?
Yes — 40CrNiMoA Q&T 48-52 HRC 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
- GB/T 3077 Alloy structural steels (2015)
- ASTM A29/A29M and SAE J404 (4340) — ASTM / SAE (2020)
- 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)
- MMPDS-2023 typical properties for 4340 steel — Battelle/FAA (2023)
- Machinery's Handbook, 31st ed. (machinability ratings) — Industrial Press (2020)
- (40CrNiMoA) — Mysteel / 1688 (2025)
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.