Steel 4330V · hardness band
Steel 4330V Q&T 40-44 HRC
Properties of the Q&T 40-44 HRC condition, compared with the other 4330V tempers.
Pick 40–44 HRC (~200 ksi UTS) for higher load capacity or wear resistance where the lower toughness and 13% elongation of this strength band are acceptable.
What is 4330V Q&T 40-44 HRC?
4330V Q&T 40-44 HRC is 4330V heat treated to Q&T 40-44 HRC — pick 40–44 HRC (~200 ksi UTS) for higher load capacity or wear resistance where the lower toughness and 13% elongation of this strength band are acceptable. 4330V Q&T 40-44 HRC has a yield strength of 1,275 MPa (185 ksi) and a tensile strength of 1,415 MPa (205 ksi) — stronger than 95% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi). 4330V Q&T 40-44 HRC 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). HR is the default condition FabDigit quotes; Q&T 40-44 HRC is available on request or by drawing note.
Advantages
- High strength — 1,275 MPa (185 ksi), better than 95% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- High embodied carbon — 2.5 kg CO₂/kg, worse than 82% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
- Difficult to machine — 40/100, worse than 76% of steel grades
4330V Q&T 40-44 HRC properties
Typical room-temperature values for 4330V Q&T 40-44 HRC — 11 properties are specific to this condition; the rest are grade-level values shared by every 4330V temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
4330V Q&T 40-44 HRC 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
4330V Q&T 40-44 HRC has a yield strength of 1,275 MPa (185 ksi) and a tensile strength of 1,415 MPa (205 ksi) — stronger than 95% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4330V Q&T 40-44 HRC is rated for continuous service to 400°C (752 °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
4330V Q&T 40-44 HRC conducts electricity at 7.8 % IACS, worse than 58% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of 4330V Q&T 40-44 HRC takes about 36 MJ of energy and emits 2.5 kg of CO₂ — more than 88% of steel grades. Typical recycled content is 25%.
Manufacturability7
4330V Q&T 40-44 HRC's machinability is fair (40/100, worse than 76% of steel grades); weldability fair (40/100); 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 4330V tempers and conditions
4330V is also supplied in 11 other conditions. The full side-by-side table is on the 4330V overview.
- HRDefaultUse hot-rolled or as-forged bar as an untreated blank when you will rough machine and then quench and temper in house; as-supplied yield is only 720 MPa.720 MPa yield · 31 HRC
- Q&T 220-240ksiUse the highest standard 220–240 ksi (1520–1655 MPa) level for weight-critical fittings and actuators, with strict control of hydrogen embrittlement and stress corrosion; elongation falls to 10%.1,410 MPa yield · 47 HRC
- Q&T 200-220ksiSpecify the AMS 6427 200–220 ksi (1380–1520 MPa) quench-and-temper level for aerospace structural parts that need high strength at 44 HRC together with good toughness.1,290 MPa yield · 44 HRC
- Q&T 40-44 HRCPick 40–44 HRC (~200 ksi UTS) for higher load capacity or wear resistance where the lower toughness and 13% elongation of this strength band are acceptable.1,275 MPa yield · 42 HRC
- Q&TChoose the most common stock quenched-and-tempered ~180 ksi (1240–1310 MPa) class at 36–40 HRC for balanced strength, toughness and machinability in aerospace structures and downhole tools.1,140 MPa yield · 38 HRC
- Q&T 32-36 HRCChoose 32–36 HRC (~155 ksi UTS), the usual band for downhole tools and shafts, when strength must rise above the sour-service cap while impact toughness stays ample.1,000 MPa yield · 34 HRC
- Q&T 28-32 HRCUse the 28–32 HRC temper (~125 ksi UTS) for downhole tools in H2S service governed by the NACE hardness cap; it gives the best toughness and the lowest strength of the tempers.860 MPa yield · 30 HRC
- NormalizedUse normalizing (air cooled from austenitizing) as the intermediate state to homogenize forgings at 302 HB in preparation for subsequent quenching and tempering.760 MPa yield · 32 HRC
- NTPick normalized and tempered for large cross-sections where reduced residual stress, moderate 725 MPa yield and stable toughness matter more than peak strength.725 MPa yield · 29 HRC
- AnnealedPick the fully annealed condition at 217 HB for maximum machinability, cold working or straightening; the part must be re-quenched and tempered afterwards.550 MPa yield · 217 HB
Working with 4330V Q&T 40-44 HRC
Is 4330V easy to machine?
In the annealed condition or at 28–36 HRC use coated carbide with low speed and heavy feed in a rigid setup; above 40 HRC prefer CBN/ceramic tooling or grinding. Rough machine with stock allowance and heat treat before final cuts to control distortion.
Can 4330V be welded?
Weldable but strongly hardening: use low-hydrogen or matching filler, preheat 200–320 °C, control interpass temperature, and temper and de-hydrogenate immediately after welding. Do not weld in the final high-strength condition without post-weld heat treatment.
Can 4330V be formed, bent or molded?
Cold forming capability is limited; bend and draw only in the annealed condition with generous radii. Forge at about 1150–950 °C and slow cool or normalize after forging to prevent cracking.
What surface finishes work on 4330V?
No corrosion resistance — typical finishes are hard chrome, electrolytic or electroless nickel, or phosphate plus primer. High-strength plated parts must be baked above 190 °C for 4–24 h to remove hydrogen; shot peening markedly improves fatigue life.
4330V 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 |
|---|---|---|
| CAMS 6427 | 0.28 – 0.33 | 0.3 |
| Mn | 0.75 – 1 | 0.88 |
| Si | 0.2 – 0.35 | 0.28 |
| Cr | 0.75 – 0.95 | 0.85 |
| Ni | 1.65 – 2 | 1.82 |
| Mo | 0.35 – 0.5 | 0.42 |
| Vgrain refinement, temper resistance | 0.05 – 0.1 | 0.07 |
| Pvacuum-melted limit | ≤ 0.01 | — |
| Svacuum-melted limit | ≤ 0.01 | — |
| Curesidual | ≤ 0.35 | — |
| Fe | balance | — |
4330V Q&T 40-44 HRC — frequently asked
What is 4330V Q&T 40-44 HRC used for?
4330V Q&T 40-44 HRC is typically used for aircraft landing gear components, aircraft structural fittings, downhole drilling tools, high-pressure oil and gas tool bodies, drive shafts and torsion members and heavy-duty lugs and fasteners. In short: aerospace ultra-strength bar.
What is the yield strength of 4330V Q&T 40-44 HRC?
4330V Q&T 40-44 HRC has a typical yield strength of 1,275 MPa (185 ksi) and a tensile strength of 1,415 MPa (205 ksi) — stronger than 95% of steel grades. Strength varies by condition: see the 12 listed tempers.
Is 4330V Q&T 40-44 HRC easy to machine?
Not especially — machinability is rated fair (40/100, worse than 76% of steel grades). In the annealed condition or at 28–36 HRC use coated carbide with low speed and heavy feed in a rigid setup; above 40 HRC prefer CBN/ceramic tooling or grinding. Rough machine with stock allowance and heat treat before final cuts to control distortion.
Can 4330V Q&T 40-44 HRC be welded?
With care — weldability is rated fair (40/100). Weldable but strongly hardening: use low-hydrogen or matching filler, preheat 200–320 °C, control interpass temperature, and temper and de-hydrogenate immediately after welding. Do not weld in the final high-strength condition without post-weld heat treatment.
What surface finishes work on 4330V Q&T 40-44 HRC?
No corrosion resistance — typical finishes are hard chrome, electrolytic or electroless nickel, or phosphate plus primer. High-strength plated parts must be baked above 190 °C for 4–24 h to remove hydrogen; shot peening markedly improves fatigue life.
Can 4330V Q&T 40-44 HRC be formed, bent or molded?
Cold forming capability is limited; bend and draw only in the annealed condition with generous radii. Forge at about 1150–950 °C and slow cool or normalize after forging to prevent cracking.
What is the maximum service temperature of 4330V Q&T 40-44 HRC?
4330V Q&T 40-44 HRC 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 4330V-HR and 4330V-CR?
HR is the default condition — use hot-rolled or as-forged bar as an untreated blank when you will rough machine and then quench and temper in house; as-supplied yield is only 720 MPa. CR: pick annealed cold-rolled sheet or strip for blanking and forming thin parts, then quench and temper to final strength; as delivered it gives 830 MPa tensile at 15% elongation. Yield strength is 720 MPa in HR versus 620 MPa in CR.
Can FabDigit make parts in 4330V Q&T 40-44 HRC?
Yes — 4330V Q&T 40-44 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
- AMS 6427 — Steel Bars, Forgings and Tubing 0.95Cr-1.8Ni-0.35Mo-0.08V (0.28-0.33C) Vacuum Melted — SAE International (2020)
- SAE J404 / UNS K23080 alloy steel composition — SAE International (2019)
- 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-17 low-alloy steel typical property tables — Battelle/FAA (2022)
- 4330V vacuum-melted alloy steel bar datasheet (aerospace/oilfield bar producers) — specialty steel producers (2023)
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.