AMS Specification 4340 High Tensile Steel Alloy Steel

AMS-S-5000

4340 High Tensile Steel – Aircraft Quality

Steel Bars, Blocks, Rings, Sheets, Forgings, and Tubing
0.80 Cr – 1.8 Ni – 0.25 Mo – 0.38-0.43 C | Aircraft Quality, Electric Furnace

AS9100D / ISO 9001

Mill Test Reports

2–4 Week Delivery

877-237-6822

Quick Specification Facts

Spec Number AMS-S-5000

Material 4340 High Tensile Steel

Spec Type AMS (Aerospace Material Specification)

Category 4340 Alloy Steel

Composition 0.80 Cr – 1.8 Ni – 0.25 Mo – 0.38-0.43 C

Condition Aircraft Quality, Electric Furnace

Product Forms Bars, Blocks, Rings, Sheets, Forgings, Tubing

Certification AS9100D / ISO 9001 with full MTR traceability

Specification Overview

AMS-S-5000 is an SAE International aerospace material specification covering 4340 high tensile steel in the forms of bars, blocks, rings, sheets, forgings, and tubing of aircraft quality. As described by SAE International, "this specification covers electric furnace steel bars and reforging stock of aircraft quality." It is widely used in aerospace, defense, and high-performance industrial applications where exceptional strength, toughness, and fatigue resistance are required.

The nominal composition of 0.80% Chromium, 1.8% Nickel, 0.25% Molybdenum, and 0.38–0.43% Carbon delivers outstanding hardenability and high tensile strength across a wide range of section sizes. The combination of Chromium, Nickel, and Molybdenum alloying elements makes 4340 one of the most versatile and widely specified high-strength steels in aerospace and defense applications, capable of achieving tensile strengths well in excess of 200 ksi when heat treated.

Available Product Forms

Bars

Blocks

Rings

Sheets

Forgings

Tubing

All product forms are supplied as Aircraft Quality, Electric Furnace material per AMS-S-5000 requirements. Custom sizes, lengths, and pre-machined forms are available upon request. Contact our materials specialists for non-standard dimensions.

Nominal Chemical Composition

Element	Symbol	Nominal %	Notes
Chromium	Cr	0.80%	Enhances hardenability and wear resistance
Nickel	Ni	1.8%	Improves toughness and hardenability
Molybdenum	Mo	0.25%	Increases hardenability and high-temperature strength
Carbon	C	0.38–0.43%	Primary strengthening element
Iron	Fe	Balance	Base metal
Manganese	Mn	0.65–0.85%	Deoxidizer; improves hardenability
Silicon	Si	0.15–0.35%	Deoxidizer; strengthening

Chemical composition ranges are nominal. Consult the current issue of AMS-S-5000 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	AMS-S-5000
Issuing Organization	SAE International (Society of Automotive Engineers)
Material Type	High Tensile Alloy Steel – Aircraft Quality
Steel Grade	4340 (AISI / UNS G43400)
Nominal Composition	0.80 Cr – 1.8 Ni – 0.25 Mo – 0.38-0.43 C
Melting Practice	Electric Furnace (Aircraft Quality)
Available Forms	Bars, Blocks, Rings, Sheets, Forgings, Tubing
Tensile Strength	Up to 260+ ksi depending on heat treatment condition
Hardenability	Excellent – deep hardening in large cross-sections
Toughness	High – excellent impact resistance at elevated strength levels
Machinability	Good – in annealed or normalized condition
Certification Available	AS9100D / ISO 9001, Certificate of Conformance, MTR

Typical Applications

Aerospace & Defense: Aircraft landing gear, structural airframe components, high-strength fasteners, actuator components, and helicopter rotor shafts requiring exceptional strength-to-weight ratios.

Power Transmission: Gears, shafts, crankshafts, connecting rods, and other drivetrain components where high fatigue strength and toughness are critical under cyclic loading.

Structural & Tooling: High-strength bolts, dies, tool holders, molds, and structural machine components requiring hardness and dimensional stability after heat treatment.

Military & Ordnance: Gun barrels, armor-related components, missile and weapons system parts, and military vehicle components requiring extreme strength and reliability.

Heavy Industrial: Mining and oil & gas drilling equipment, large pressure vessels, pump shafts, and heavy-duty industrial machinery components exposed to high stress and impact loads.

Frequently Asked Questions – AMS-S-5000

What is AMS-S-5000 and what does it cover?

AMS-S-5000 is an SAE International aerospace material specification covering 4340 high tensile steel in the forms of bars, blocks, rings, sheets, forgings, and tubing of aircraft quality. As stated by SAE International, "this specification covers electric furnace steel bars and reforging stock of aircraft quality." The nominal composition of 0.80% Chromium, 1.8% Nickel, 0.25% Molybdenum, and 0.38–0.43% Carbon delivers exceptional strength, hardenability, and toughness. It is widely used in aerospace, defense, and high-performance industrial applications where extreme tensile and fatigue strength are required.

What is the difference between AMS-S-5000 and AMS 6414?

Both AMS-S-5000 and AMS 6414 cover 4340 alloy steel, but there are important distinctions: (1) AMS-S-5000 covers electric furnace (EF) melted aircraft quality material in the forms of bars, blocks, rings, sheets, forgings, and tubing; (2) AMS 6414 specifically covers vacuum induction melted / vacuum arc remelted (VIM/VAR) or consumable electrode melted 4340 steel, which yields a higher cleanliness level and improved fatigue properties for the most critical aerospace applications; (3) AMS 6414 is typically specified for fracture-critical parts such as landing gear and primary flight structure, while AMS-S-5000 is used for a broader range of aircraft quality applications. Your specific program requirements and drawing callouts will determine which specification is appropriate.

Does Aero-Vac supply AMS-S-5000 with full mill test reports and certifications?

Yes. All AMS-S-5000 material supplied by Aero-Vac is fully traceable to mill test reports (MTRs) confirming chemical composition and mechanical properties per the specification. We are AS9100D/ISO 9001 certified with a 99.6% quality rating. Every order ships with certificates of conformance, material certifications, and chemical/mechanical test reports. Electronic delivery of all documentation is available for fast turnaround. If your program requires additional special process certifications, our quality team can coordinate as needed.

What forms and sizes of AMS-S-5000 does Aero-Vac stock?

Aero-Vac maintains inventory of AMS-S-5000 4340 steel in multiple product forms including bars (round, flat, square, and hex), blocks, rings, sheets, forgings, and tubing. We carry a range of standard sizes across all these forms and can provide custom-cut lengths, discs, blocks, and near-net shapes from our in-house processing facility at the Port of Kalama. For non-standard dimensions, our team can source from our global supplier network. Contact us with your specific size requirements and we will provide a prompt quote with availability and lead time.

What are the typical lead times for AMS-S-5000 material?

In-stock AMS-S-5000 material is typically available for same-day or next-day shipment. For custom-cut or specially processed orders, our standard lead time is 2–4 weeks—significantly faster than the industry average of 8–12 weeks. Specialty forgings or items requiring mill production may require 4–8 weeks depending on quantity and form. We prioritize urgent aerospace and defense requirements and will always provide honest, upfront delivery estimates. Rush processing is available on select items.

Can Aero-Vac provide value-added processing for AMS-S-5000 material?

Yes. Aero-Vac operates a complete in-house processing facility at our Port of Kalama location. For AMS-S-5000 4340 steel, we offer precision saw cutting (including disc, block, and ring cutting), surface grinding, trepanning, turning, milling, and heat treatment. We also provide comprehensive mechanical and non-destructive testing services in-house. Having all capabilities under one roof allows for faster turnaround, tighter quality control, and reduced overall cost compared to using multiple vendors. Contact us to discuss your specific processing requirements.

Need AMS-S-5000 material or a custom quote?

Our 4340 alloy steel specialists can provide fast pricing, availability, and technical guidance for your AMS-S-5000 requirements.