Steel 4330V
AISI/SAE 4330V · UNS K23080 · AMS 6427
4330V is a vacuum-melted (VIM/VAR or vacuum-degassed) Ni-Cr-Mo-V low-alloy ultra-high-strength steel supplied to aerospace specifications such as AMS 6427, UNS K23080.
Values for the HR condition
4330V tempers and conditions
4330V is supplied in 12 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 12 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full anneal, softest machinable condition | Pick the fully annealed condition at 217 HB for maximum machinability, cold working or straightening; the part must be re-quenched and tempered afterwards. | 550 | 760 | 22 | 217 HB | — |
Cold rolled | 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. | 620 | 830 | 15 | 24 HRC | 8 % IACS |
HRDefault Hot rolled | 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. | 720 | 1,000 | 14 | 31 HRC | 7.8 % IACS |
Normalized and tempered | Pick normalized and tempered for large cross-sections where reduced residual stress, moderate 725 MPa yield and stable toughness matter more than peak strength. | 725 | 930 | 18 | 29 HRC | 8 % IACS |
Cold drawn | Choose annealed-then-cold-drawn bar for small diameters that need dimensional accuracy and a clean surface with no further heat treatment; elongation drops to 12%. | 760 | 900 | 12 | 27 HRC | 7.9 % IACS |
normalized (air cooled from austenitizing) | Use normalizing (air cooled from austenitizing) as the intermediate state to homogenize forgings at 302 HB in preparation for subsequent quenching and tempering. | 760 | 1,035 | 16 | 32 HRC | 7.8 % IACS |
Tempered to ~125 ksi UTS, sour-service hardness cap | Use 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 | 965 | 19 | 30 HRC | — |
Tempered to ~155 ksi UTS | Choose 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 | 1,105 | 17 | 34 HRC | — |
Quenched and tempered | Choose 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 | 1,275 | 15 | 38 HRC | — |
Tempered to ~200 ksi UTS | 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. | 1,275 | 1,415 | 13 | 42 HRC | — |
AMS 6427 aerospace strength level | Specify 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 | 1,450 | 12 | 44 HRC | — |
highest standard strength level | Use 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 | 1,590 | 10 | 47 HRC | — |
What is 4330V?
4330V is a vacuum-melted (VIM/VAR or vacuum-degassed) Ni-Cr-Mo-V low-alloy ultra-high-strength steel supplied to aerospace specifications such as AMS 6427, UNS K23080. The vanadium refines grain size and suppresses temper embrittlement, so fracture toughness and low-temperature impact properties stay high at 1100–1600 MPa strength levels; it is stocked as bar and forging stock in Q&T conditions from 28–32 HRC up to 220–240 ksi, with a default of 720 MPa yield, 1000 MPa tensile, 14 % elongation and 300 HB. It has no corrosion resistance and must be plated or painted, is sensitive to hydrogen embrittlement and stress-corrosion cracking at high strength, and needs preheat plus post-weld tempering. 4330V 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). 4330V has a yield strength of 720 MPa (104 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 82% of steel grades. Elongation at break is 14% and the elastic modulus is 205 GPa (29.7 Msi).
What is 4330V used for?
- Aircraft landing gear components
- Aircraft structural fittings
- Downhole drilling tools
- High-pressure oil and gas tool bodies
- Drive shafts and torsion members
- Heavy-duty lugs and fasteners
- Missile and rocket structural parts
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- High strength — 720 MPa (104 ksi), better than 82% of steel grades
Limitations
- High embodied carbon — 2.5 kg CO₂/kg, worse than 82% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
4330V properties
Typical room-temperature values for 4330V-HR; bars are the position among steel grades.
Physical3
4330V 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 has a yield strength of 720 MPa (104 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 82% of steel grades. Elongation at break is 14% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4330V is rated for continuous service to 400°C (752 °F). It conducts heat at 43 W/m·K (24.8 BTU/hr·ft·°F), better than 51% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
4330V conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of 4330V takes about 36 MJ of energy and emits 2.5 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 25%.
Manufacturability7
4330V's machinability is fair (45/100, worse than 65% of steel grades); weldability fair (45/100); formability poor (28/100).
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. 4330V is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 4330V
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.
Manufacturability
The process limits FabDigit applies to 4330V. Every 4330V part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better45 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Fair28 / 100 |
|---|---|
| Weldability | Better45 / 100 |
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 |
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.
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).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 4330V in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- K23080
- AMS
- 6427
How much does 4330V cost?
4330V is a standard-cost steel ($$), cheaper than about 62% 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.
4330V — frequently asked
What is 4330V used for?
4330V 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?
4330V has a typical yield strength of 720 MPa (104 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 82% of steel grades. Strength varies by condition: see the 12 listed tempers.
Is 4330V easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% 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 be welded?
With care — weldability is rated fair (45/100). 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?
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 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?
4330V 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.
How much does 4330V cost?
4330V is a standard-cost steel ($$), cheaper than about 62% 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.
Can FabDigit make parts in 4330V?
Yes — 4330V is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. 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; 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.