4330 MOD Alloy Steel – AMS 6411 VAR – UNSK23080
It is a low alloy steel capable of being heat treated to high strength levels.
4330 MOD VAR AMS 6411 is AISI 4330 Steel modified with the addition of Vanadium. Vanadium is added to improve impact strength and hardenability. This is a premium aircraft quality steel usually produced as a consumable electrode remelted product (VAR). AMS 6411 also allows the 2nd melt to be ESR (Electro-Slag Remelting) when specified by the end-user.
<<4330 MOD Alloy Steel – AMS 6411 VAR – UNSK23080 DATA SHEET>>
4330 Mod VAR Alloy Steel Applications:
Aerospace applications are those requiring high tensile strength and good ductility, coupled with high impact strength, superior transverse properties, and hardness. The carbon content lower than AISI 4340 makes this grade useful for applications that involve shock loading or stress concentration.
Common Trade Names:
4330+V
4330 CEVM
4330 Modified
4330M
Lescalloy 4330+V VAC-ARC
4330V
SAE 4330M
34CrNiMo6V
HS220-27 Alloy Steel
Common Specifications:
AMS 6411
AMS 6427 except VAR
BMS 7-122
BMS 7-27 except VAR
MIL-S-8699
EMS 96242
CE 0906
FMS 1012
GM 1010
Chemical Composition:
| Symbol | Element | Min % | Max % |
| C | Carbon | 0.28% | 0.33% |
| Mn | Manganese | 0.65% | 1.00% |
| Si | Silicon | 0.15% | 0.35% |
| P | Phosphorus | 0.015% | |
| S | Sulfur | 0.015% | |
| Cr | Chromium | 0.75% | 1.00% |
| Ni | Nickel | 1.65% | 2.00% |
| Mo | Molybdenum | 0.35% | 0.50% |
| V | Vanadium | 0.05% | 0.10% |
| Cu | Copper | 0.35% |
Longitudinal Tensile Properties:
| Property | Value |
| Tensile Strength | 220 ksi |
| Yield Strength 0.2% offset | 185 ksi |
| Elongation | 10% |
| Reduction of Area | 35% |
After heat treating specimens per paragraph 3.4.5
Macrostructure standards:
| Class | Condition | Severity |
| 1 | Freckles | A |
| 2 | White Spots | A |
| 3 | Radial Segregation | B |
| 4 | Ring Pattern | B |
Fabrication
| Forging | 1950° – 2255° F (1066° – 1235° C) |
| Machinability | Normalize & temper at 1250° F (675° C) prior to machining. Machining at max strength is usually followed by stress relieving |
| Welding | Arc or Resistance Flash weldable |
Heat Treatment
| Type of Heat Treating | Process |
| Normalize | 1600° – 1700° (870° – 925° C), air cool |
| Anneal | 1525° – 1575° (830° – 860° C), furnace cool |
| Harden | Austenitize 1550° – 1600° (845° – 870° C), water, oil, or polymer quench |
| Temper | 500° – 700° (260° – 240° C) for tensile 220-240 ksi |
Minimum Transverse Tensile Properties per AMS 6411:
| Cross-section Area | Tensile Strength | Yield Strength 0.2% Offset | Avg. Reduction of Area | Individual Reduction of Area |
| Up to 144 in2, incl | 220 ksi | 185 ksi | 35% | 30% min |
| Over 144 in2 to 225 in2, incl | 220 ksi | 185 ksi | 30% | 25% min |
| Over 225 in2 | 220 ksi | 185 ksi | 25% | 20% min |
