AMS 6257 Alloy Steel Bars and Forgings

AMS 6257 Alloy Steel Grade AISI 4340 MOD 

AMS 6257 Alloy Steel

What is AMS 6257?

AMS 6257 is a specification for a particular type of alloy steel, standard set by the Society of Automotive Engineers (SAE) to used primarily in the aerospace industry.  The number “6257” refers to a specific alloy composition within the AMS (Aerospace Material Specification) system. AMS 6257 alloy steel is a high-strength, low-alloy steel, generally used in forms such as bars and forgings.

AMS 6257 Bars Supplier

Your Reliable Source for High-Quality AMS 6257 Alloy Steel Bars

As a leading supplier of AMS 6257 Bars, we take pride in offering a product that sets the standard in terms of strength, durability, and performance. Our AMS 6257 Bars are crafted to meet the aerospace industry specifications and are also well-suited for a variety commercial use.

Product Overview:

  • AMS 6257 Bars Physical Form: The term “bar” in AMS 6257 steel bar refers to the physical shape of the material. These bars are typically long, straight, and uniform in cross-section, available in various diameters and lengths. AMS 6257 bar can be cut, machined, or otherwise processed into specific parts or components of aircraft.

Key Features:

  • High Strength and Toughness: Ideal for applications requiring materials that can withstand extreme stress and strain.
  • Excellent Fatigue Resistance: Perfect for components experiencing cyclic stress, providing longevity and reliability.
  • Versatile and Durable: Perfect for a wide range of applications including aerospace, automotive, defense and industrial machinery.

Customization and Specifications:

  • Tailored Solutions: We offer AMS 6257 Bars in various sizes and lengths, catering to specific project requirements.
  • Quality Assurance: Each bar undergoes stringent quality checks to ensure it meets AMS standards and client specifications.


  • Aerospace Components: Landing gear, structural members, fasteners, and more.
  • Automotive and Racing: High-performance vehicle components where strength and durability are paramount.
  • Industrial and Engineering: Heavy machinery parts, high-strength tools, and equipment.

Commitment to Excellence:

  • Customer Service: Our knowledgeable team is here to assist with selection, customization, and after-sales support.
  • Timely Delivery: We understand the importance of deadlines and strive to deliver your order promptly and efficiently.

For more information about our AMS 6257 Bars or to discuss your specific needs, call us at 714-632-0140 or Toll-Free at 800-854-6777.

AMS 6257 Bars Forging Service

We are proud to offer a specialized AMS 6257 bar forging service. Our forging service focuses on producing forged parts from AMS 6257 steel bars. .

Key features of our AMS 6257 bar forging service:

  1. Expertise in High-Grade Steel: Our team possesses deep expertise in working with AMS 6257 steel, ensuring that each forged part meets the stringent standards required in aerospace and other high-stress environments.
  2. Custom Forging Capabilities: We offer custom forging to client specifications, creating parts that fit exacting requirements in terms of size, shape, and mechanical properties. Our state-of-the-art forging processes include open die, closed die, and ring rolling.
  3. Advanced Heat Treatment: Post-forging, we employ advanced heat treatment techniques to enhance the mechanical properties of AMS 6257 steel, such as increased hardness, strength, and resistance to fatigue. Processes like annealing, quenching, and tempering are meticulously applied.
  4. Precision Machining: Following forging, our precision machining services ensure that each component meets exact dimensional tolerances and surface finish requirements. We use the latest CNC machinery.
  5. Quality Assurance: Each forged part is inspected and tested to ensure it meets or exceeds the AMS 6257 standards and client specifications. This includes dimensional checks, mechanical testing, and material analysis.

AMS 6257 Uses

Here are some of the primary uses of AMS 6257 steel:

  1. Aerospace Industry: The primary sector that utilizes AMS 6257 is the aerospace industry. Used in Aircraft landing gear, Airframe parts, Flap track.
  2. Automotive and Transportation: AMS 6257 is used in high-performance and racing vehicles where strength, durability, and lightweight materials are crucial.
  3. Defense and Military Applications: AMS 6257 is used in the construction of various components of military vehicles, aircraft, and naval ships.
  4. Industrial Machinery and Tooling: AMS 6257 is used in the manufacturing of heavy-duty industrial machinery and tooling.
  5. Energy Sector: In oil and gas extraction, AMS 6257 is used for manufacturing drilling and exploration equipment.
  6. Sporting Goods: Mountain climbing equipment, high-performance bicycle components, and competitive sports equipment, may utilize AMS 6257.
  7. Medical Devices and Instruments: AMS 6257 used for surgical instruments, orthopedic implants, and other devices where strength and precision are critical.
  8. General Engineering: AMS 6257 is a preferred material for parts that require a combination of high strength, toughness, and resistance to wear and fatigue.

AMS 6257 Composition & Properties

Here are some key Composition and Properties AMS 6257 for Aerospace Industry:


Approximate % or Description (for Aerospace Industry)

Carbon (C)

0.1-0.2% – Increases hardness and strength

Manganese (Mn)

0.6-1.0% – Contributes to strength and hardenability

Silicon (Si)

0.2-0.4% – Used for strengthening and deoxidizing

Chromium (Cr)

0.7-1.2% – Enhances hardness, strength, and corrosion resistance

Nickel (Ni)

1.4-2.0% – Adds toughness, corrosion and oxidation resistance

Molybdenum (Mo)

0.2-0.4% – Increases hardenability and strength

Phosphorus (P)

<0.025% – Can increase strength (kept low to avoid brittleness)

Sulfur (S)

<0.025% – Improves machinability (kept low)

High Strength

– – Essential for structural and critical components

Good Fatigue Resistance

– – Crucial for repeated stress endurance


– – High, enhanced by heat treatment

Heat Treatability

– – Can be tailored for desired mechanical properties


– – Reasonable despite high strength


– – Moderate, requires careful welding techniques

Corrosion Resistance

– – Offers some resistance, important for longevity


– – Allows deformation under stress, aids in manufacturing



Note: AMS 6257 composition can vary slightly based on the manufacturer and specific applications. AMS 6257 possesses a set of properties suitable for aerospace industry. Please note that the percentages provided are approximate and can vary. For exact specifications, it’s always best to refer to the manufacturer’s data sheet or the AMS 6257 standard itself.

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