Specification Overview
GM 1010 is a Northrop Grumman proprietary specification covering 4330M, an aircraft quality low alloy steel (vanadium modified), in the form of bars, forgings, mechanical tubing, and forging stock. This specification is based on AMS-6411 per SAE International and is used for parts requiring a combination of high tensile strength and good ductility with relatively high impact strength and hardness. The alloy is also commonly referred to as GRUMMAN 4330 (V Mod) and is produced by vacuum melting to ensure exceptional cleanliness and consistency. The nominal composition of 0.88% Chromium, 1.8% Nickel, 0.42% Molybdenum, 0.08% Vanadium, and 0.28–0.33% Carbon delivers an outstanding balance of mechanical properties suited to critical aerospace structural applications.
Per the specification description: "This specification covers an aircraft quality, low alloy steel in the form of bars, forgings, mechanical tubing, and forging stock. These products have been used typically for parts requiring a combination of high tensile strength and good ductility with relatively high impact strength and hardness, but usage is not limited to such applications. Certain design and processing procedures may cause these products to become susceptible to stress-corrosion cracking after heat treatment. ARP1110 recommends practices to minimize such conditions." The vanadium addition refines grain size and enhances strength and toughness, while vacuum melting ensures a high-purity, inclusion-free microstructure required for demanding aerospace applications.
Available Product Forms
GM 1010 material is supplied as Bars, Forgings, Mechanical Tubing, and Forging Stock per specification requirements. Round bar, hex bar, and forged billet forms are available in a range of diameters and cross-sections. Custom forgings, near-net-shape forgings, and machined blanks are available upon request. Contact our materials specialists for non-standard dimensions or custom forging requirements.
Nominal Chemical Composition
| Element |
Symbol |
Nominal % |
Notes |
| Carbon |
C |
0.28–0.33% |
Primary hardening element; controls hardenability and strength |
| Chromium |
Cr |
~0.88% (0.75–1.00%) |
Improves hardenability, wear resistance, and toughness |
| Nickel |
Ni |
~1.8% (1.65–2.00%) |
Enhances toughness, impact strength, and low-temperature ductility |
| Molybdenum |
Mo |
~0.42% (0.35–0.50%) |
Improves hardenability, creep resistance, and prevents temper embrittlement |
| Vanadium |
V |
~0.08% (0.05–0.10%) |
Grain refiner; improves strength, toughness, and fatigue resistance (V Mod designation) |
| Manganese |
Mn |
0.60–0.90% |
Deoxidizer; improves hardenability and strength |
| Silicon |
Si |
0.20–0.35% |
Deoxidizer; contributes to strength |
| Iron |
Fe |
Balance |
Base metal |
Chemical composition ranges are nominal. Consult the current issue of GM 1010 and AMS-6411 for precise minimum/maximum requirements. Aero-Vac provides full mill test reports (MTRs) with certified chemistry for every order.
Key Properties & Specification Details
| Property / Attribute |
Details |
| Specification Number |
GM 1010 |
| Issuing Organization |
Northrop Grumman Corporation |
| Based On |
AMS-6411 (SAE International) |
| Material Type |
Aircraft Quality Low Alloy Steel – Bars, Forgings, Mechanical Tubing, and Forging Stock |
| Alloy Name |
4330M (V Mod) – also known as GRUMMAN 4330 (V Mod) |
| Nominal Composition |
0.88Cr 1.8Ni 0.42Mo 0.08V 0.28-0.33C |
| Melt Practice |
Vacuum Melted |
| Available Forms |
Bars, Forgings, Mechanical Tubing, Forging Stock |
| Tensile Strength |
High – designed for critical aerospace structural applications requiring high tensile strength combined with good ductility |
| Impact Strength |
Very Good – relatively high impact strength and hardness; good toughness characteristics |
| Machinability |
Good in annealed condition; moderate in heat treated condition |
| Weldability |
Fair – pre- and post-weld heat treatment recommended; stress-corrosion cracking risk after heat treatment must be managed per ARP1110 |
| Magnetic Properties |
Magnetic (ferritic/martensitic) |
| Certification Available |
AS9100D / ISO 9001, Certificate of Conformance, MTR |
Typical Applications
Aerospace Structural Components: Primary and secondary aircraft structural parts requiring a combination of high tensile strength, good ductility, and relatively high impact strength and hardness, including fuselage frames, wing spars, and attachment fittings.
Landing Gear & Undercarriage: Landing gear struts, actuator housings, and undercarriage components where high strength, toughness, and fatigue resistance under cyclic loading are critical requirements.
Fasteners, Bolts & Shafts: High-strength aerospace fasteners, bolts, studs, and shafts for critical structural joints requiring a combination of tensile strength and shear resistance.
Defense & Ordnance Applications: Missile components, gun parts, ordnance hardware, and defense system structural members requiring reliable high-strength performance under demanding mechanical and environmental conditions.
Forged Structural Parts: Near-net-shape forgings and forging stock for complex aerospace and defense structural parts where grain flow alignment and high mechanical properties are essential for fatigue and fracture resistance.
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