Steel 4330 · supply condition · default condition
Steel 4330-HR
Properties of the HR condition, compared with the other 4330 tempers.
Cheapest mill form for parts that will be heat treated after rough machining or forging.
What is 4330-HR?
4330-HR is 4330 supplied in the HR condition — cheapest mill form for parts that will be heat treated after rough machining or forging. 4330-HR 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). 4330-HR 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).
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- High strength — 600 MPa (87 ksi), better than 77% of steel grades
4330-HR properties
Typical room-temperature values for 4330-HR — 9 properties are specific to this condition; the rest are grade-level values shared by every 4330 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
4330-HR 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-HR 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-HR is rated for continuous service to 370°C (698 °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).
Electrical2
4330-HR has an electrical resistivity of 2.2×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is not recommended (14/100), better than 70% of steel grades.
Sustainability4
Producing a kilogram of 4330-HR 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-HR's machinability is fair (52/100, better than 52% of steel grades); weldability fair (40/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 4330 tempers and conditions
4330 is also supplied in 9 other conditions. The full side-by-side table is on the 4330 overview.
- HRDefaultCheapest mill form for parts that will be heat treated after rough machining or forging.600 MPa yield · 26 HRC
- Q&T-150Highest commercial strength level for weight-critical shafts and landing-gear type parts; watch notch sensitivity and hydrogen embrittlement.1,100 MPa yield · 39 HRC
- Q&TStandard stocked condition for drill-tool and machined structural parts needing high strength with good toughness.965 MPa yield · 34 HRC
- Q&T-130Most common 4330V drilling/aerospace forging class; high strength with still-good CVN.960 MPa yield · 34 HRC
- Q&T-120Balanced oilfield class for tool joints and downhole housings.880 MPa yield · 30 HRC
- Q&T-110Lower-strength sour-service oriented class; softest Q&T level with best impact toughness and best HIC/SSC margin.800 MPa yield · 26 HRC
- CDTight-tolerance small-diameter bar with raised yield strength; no further heat treatment.790 MPa yield · 29 HRC
- NormalizedUniform fine grain and predictable response before final hardening; used for large forgings.650 MPa yield · 28 HRC
- AnnealedPick for maximum machinability and cold working before final quench and temper.570 MPa yield · 210 HB
Working with 4330-HR
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.
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.
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 | — |
4330-HR — frequently asked
What is 4330-HR used for?
4330-HR 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-HR?
4330-HR 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-HR 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-HR be welded?
With care — weldability is rated fair (40/100). 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-HR?
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-HR 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-HR?
4330-HR is rated for continuous use to about 370°C (698 °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.
Can FabDigit make parts in 4330-HR?
Yes — 4330-HR 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 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.