Steel 4330
AISI/SAE 4330
4330 is a nickel-chromium-molybdenum low-alloy steel with about 0.30 % C, commonly supplied as the vacuum-melted 4330V/4330M modifications; it belongs to the 4340 family but with lower carbon, keeping hardenability high while improving toughness and resistance to H2S cracking.
Values for the HR condition
4330 tempers and conditions
4330 is supplied in 10 conditions, soft to hard. HR 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 |
|---|---|---|---|---|---|---|
full anneal, softest condition | Pick for maximum machinability and cold working before final quench and temper. | 570 | 760 | 22 | 210 HB | — |
HRDefault Hot rolled | Cheapest mill form for parts that will be heat treated after rough machining or forging. | 600 | 900 | 18 | 26 HRC | 8 % IACS |
Normalized (and optionally tempered) | Uniform fine grain and predictable response before final hardening; used for large forgings. | 650 | 930 | 19 | 28 HRC | 8 % IACS |
Cold drawn | Tight-tolerance small-diameter bar with raised yield strength; no further heat treatment. | 790 | 950 | 12 | 29 HRC | 8 % IACS |
quenched & tempered to 110 ksi (760 MPa) min yield | Lower-strength sour-service oriented class; softest Q&T level with best impact toughness and best HIC/SSC margin. | 800 | 930 | 19 | 26 HRC | — |
Cold rolled | Thin flat product with good surface finish, normally re-heat-treated after forming. | 820 | 970 | 10 | 30 HRC | 8 % IACS |
quenched & tempered to 120 ksi (830 MPa) min yield | Balanced oilfield class for tool joints and downhole housings. | 880 | 1,000 | 18 | 30 HRC | — |
quenched & tempered to 130 ksi (900 MPa) min yield | Most common 4330V drilling/aerospace forging class; high strength with still-good CVN. | 960 | 1,080 | 16 | 34 HRC | — |
Quenched and tempered | Standard stocked condition for drill-tool and machined structural parts needing high strength with good toughness. | 965 | 1,100 | 16 | 34 HRC | — |
quenched & tempered to 150 ksi (1035 MPa) min yield | Highest commercial strength level for weight-critical shafts and landing-gear type parts; watch notch sensitivity and hydrogen embrittlement. | 1,100 | 1,240 | 14 | 39 HRC | — |
What is 4330?
4330 is a nickel-chromium-molybdenum low-alloy steel with about 0.30 % C, commonly supplied as the vacuum-melted 4330V/4330M modifications; it belongs to the 4340 family but with lower carbon, keeping hardenability high while improving toughness and resistance to H2S cracking. It is quenched and tempered to 110, 120, 130 or 150 ksi minimum yield for drill string and downhole tools, valve bodies, landing gear and high-strength forgings; default Q&T bar is 600 MPa yield, 900 MPa tensile, 18 % elongation and 262 HB (26 HRC). Corrosion resistance is that of plain carbon steel, welding needs preheat and post-weld temper, and the highest strength levels are sensitive to hydrogen embrittlement and stress raisers. 4330 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). 4330 has a yield strength of 600 MPa (87 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 77% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi).
What is 4330 used for?
- Drill collars and tool joints
- Downhole tool bodies
- Wellhead and valve bodies
- Aircraft landing gear components
- High-strength forgings
- Heavy-duty shafts and gear blanks
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
- High strength — 600 MPa (87 ksi), better than 77% of steel grades
4330 properties
Typical room-temperature values for 4330-HR; bars are the position among steel grades.
Physical3
4330 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
4330 has a yield strength of 600 MPa (87 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 77% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4330 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
4330 conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (14/100), better than 70% of steel grades.
Sustainability4
Producing a kilogram of 4330 takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability7
4330's machinability is fair (52/100, better than 52% of steel grades); weldability fair (45/100); formability fair (35/100).
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. 4330 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 4330
Is 4330 easy to machine?
Machine in the annealed or ≤32 HRC Q&T condition with rigid setups, carbide inserts and moderate speeds; above 38 HRC prefer grinding or ceramic/CBN tooling.
Can 4330 be welded?
Weldable by GTAW/GMAW with low-hydrogen or matching filler, 200–320 °C preheat, controlled interpass and a post-weld temper below the original tempering temperature.
Can 4330 be formed, bent or molded?
Hot forge 1100–1230 °C, finish above 950 °C, then normalize; cold forming is limited to the annealed state with generous radii.
Manufacturability
The process limits FabDigit applies to 4330. Every 4330 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better52 / 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 | Fair35 / 100 |
|---|---|
| Weldability | Better45 / 100 |
4330 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 |
|---|---|---|
| C4330V modified | 0.28 – 0.33 | 0.3 |
| Mn | 0.75 – 1 | 0.88 |
| Si | 0.2 – 0.35 | 0.28 |
| Ni | 1.65 – 2 | 1.85 |
| Cr | 0.75 – 0.95 | 0.85 |
| Mo | 0.35 – 0.45 | 0.4 |
| Vpresent in 4330V / 4330M; omitted in plain 4330 | 0.05 – 0.1 | 0.07 |
| Pmax; ≤0.010 for VAR aerospace | ≤ 0.02 | |
| Smax; ≤0.005 for sour service | ≤ 0.02 | |
| Curesidual max | ≤ 0.35 | |
| Fe | balance |
What surface finishes work on 4330?
No anodizing — protect with manganese/zinc phosphate, black oxide, Zn-Ni or Cd plate; bake at ~190 °C after plating to relieve hydrogen, and shot peen fatigue-critical fillets.
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
How much does 4330 cost?
4330 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.
4330 — frequently asked
What is 4330 used for?
4330 is typically used for drill collars and tool joints, downhole tool bodies, wellhead and valve bodies, aircraft landing gear components, high-strength forgings and heavy-duty shafts and gear blanks. In short: high-strength Cr-Mo-Ni bar.
What is the yield strength of 4330?
4330 has a typical yield strength of 600 MPa (87 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 77% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 4330 easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Machine in the annealed or ≤32 HRC Q&T condition with rigid setups, carbide inserts and moderate speeds; above 38 HRC prefer grinding or ceramic/CBN tooling.
Can 4330 be welded?
With care — weldability is rated fair (45/100). Weldable by GTAW/GMAW with low-hydrogen or matching filler, 200–320 °C preheat, controlled interpass and a post-weld temper below the original tempering temperature.
What surface finishes work on 4330?
No anodizing — protect with manganese/zinc phosphate, black oxide, Zn-Ni or Cd plate; bake at ~190 °C after plating to relieve hydrogen, and shot peen fatigue-critical fillets.
Can 4330 be formed, bent or molded?
Hot forge 1100–1230 °C, finish above 950 °C, then normalize; cold forming is limited to the annealed state with generous radii.
What is the maximum service temperature of 4330?
4330 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 4330-HR and 4330-CR?
HR is the default condition — cheapest mill form for parts that will be heat treated after rough machining or forging. CR: thin flat product with good surface finish, normally re-heat-treated after forming. Yield strength is 600 MPa in HR versus 820 MPa in CR.
How much does 4330 cost?
4330 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 4330?
Yes — 4330 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 6411 — Steel Bars, Forgings and Tubing 0.95Cr 1.8Ni 0.40Mo 0.08V (4330V) — SAE International (2019)
- ASTM A29/A29M — General Requirements for Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (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-17, low-alloy steel chapters — Battelle/FAA (2022)
- 4330V alloy steel bar and forging data — specialty bar producers (e.g. TimkenSteel/Latrobe-type datasheets) (2021)
- NACE MR0175 / ISO 15156 — Materials for use in H2S-containing environments — NACE/ISO (2015)
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.