ThePipingMart Blog Grades AMS 6349 Alloy Steel – Composition, Properties, and Uses

AMS 6349 Alloy Steel – Composition, Properties, and Uses

AMS 6349

SAE – AMS 6349 is a high-quality steel alloy in the aircraft-grade steel category. It is primarily known for its exceptional strength, durability, and high-temperature resistance, which enables it to withstand harsh environments and extreme conditions. Due to these unique properties, this alloy is widely used in various critical applications, including high-performance structural components, propulsion systems, engine parts, and landing gears. In this blog, we will explore in detail the composition, physical and mechanical properties, hardness, heat treatment, and uses of AMS 6349.

What is AMS 6349?

AMS 6349 (also known as SAE – AISI 4130 Alloy Steel) is a metal type specifically designed for high-stress applications. This metal is known for its impressive strength and durability, making it a top choice in the aviation, defence, and aerospace industries. AMS6349 metal is also known for its excellent heat resistance properties, making it a popular choice in high-temperature environments. With its remarkable properties, this metal has become crucial in many complex systems and machinery, ensuring their longevity and optimal performance.

What Form is AMS 6349 Available at Piping Mart?

  • Alloy Steel AISI 4130 Bars

AMS 6349 Composition

The composition of AMS 6349 steel includes elements such as chromium, molybdenum, and vanadium, which provide the alloy with excellent corrosion resistance and high-temperature stability. Other notable elements in this steel alloy include carbon, manganese, silicon, nickel, and iron. The steel is manufactured using conventional melting and casting methods and precise heat treatment to ensure high purity and quality.

C Si Mn P S Cr Mo Fe
Min 0.28 0.15 0.40 0.80 0.15 0.00
Max 0.33 0.35 0.60 0.035 0.040 1.10 0.25 0.00

AMS 6349 Physical Properties

AMS 6349 steel plate has exceptional physical properties that suit high-stress applications. The density of this steel is about 7.85 g/cm3, which is relatively high compared to other common steel alloys. It has a melting point of around 1480°C, and its thermal conductivity is about 48 W/m°C, which is relatively low, indicating low thermal losses in high-temperature applications.

Properties Metric Imperial
Density 7.85 g/cm3 0.284 lb/in³
Melting point 1432°C 2610°F

AMS 6349 Mechanical Properties

The mechanical properties of AMS 6349 steel sheet are what make it one of the best choices for high-performance applications. The alloy has a tensile strength of up to 210 ksi, and its yield strength ranges from 160 to 180 ksi. It also has a high fatigue strength, enabling it to withstand repetitive stress cycles without cracking or breaking. In addition, its flexibility and toughness make it easy to work with and shape into the desired form.

Properties Metric
Tensile strength, ultimate 560 MPa
Tensile strength, yield 460 MPa
Modulus of elasticity 190-210 GPa
Bulk modulus (Typical for steel) 140 GPa
Shear modulus (Typical for steel) 80 GPa
Poissons ratio 0.27-0.30
Elongation at break (in 50 mm) 21.50%
Reduction of area 59.6
Hardness, Brinell 217
Hardness, Knoop (Converted from Brinell hardness) 240
Hardness, Rockwell B (Converted from Brinell hardness) 95
Hardness, Rockwell C (Converted from Brinell hardness, value below normal HRC range, for comparison purposes only.) 17
Hardness, Vickers (Converted from Brinell hardness) 228
Machinability (Annealed and cold drawn. Based on 100% machinability for AISI 1212 steel.) 70

AMS 6349 Equivalents

AMS 6348 AMS 6371 ASTM A331 ASTM A829 DIN 1.7218
AMS 6350 AMS 6373 ASTM A506 MIL S-18729 UNI 25 CrMo 4
AMS 6351 AMS 6374 ASTM A507 MIL S-6758 JIS SCCrM 1
AMS 6360 AMS 6528 ASTM A513 SAE J1397 JIS SCM 2
AMS 6361 AMS 7496 ASTM A519 SAE J404 SS 2225
AMS 6362 ASTM A29 ASTM A646 SAE J412 B.S. CDS 110
AMS 6370 ASTM A322 ASTM A752 AFNOR 25 CD 4 (S) SAE J770

AMS 6349 Specifications

Country USA BS BS Japan
Standard ASTM A29 EN 10250/EN10083 BS 970 JIS G4105
Grades 4130 25CrMo4/1.7218 708A25/708M25 SCM430

AMS 6349 Uses

AMS 6349 steel bars is a versatile alloy used in various critical applications, such as aircraft and aerospace components, defence equipment, marine applications, and automotive parts. Its excellent strength, high temperature, and corrosion resistance make it an ideal choice in harsh environments and extreme conditions. It is also commonly used to manufacture high-stress components, such as engine parts, landing gears, and structural components.

AMS 6349 Hardness

AMS 6349 steel is known for its high hardness, measured using the Rockwell scale or Brinell hardness test methods. The steel’s hardness can range from 35 HRC to 45 HRC, depending on the heat treatment method used. This high hardness makes it an ideal choice for applications that require excellent wear and fatigue resistance, such as landing gears, engine components, and transmission parts.

AMS 6349 Heat Treatment

Heat treatment is an essential process used to enhance the mechanical properties of AMS 6349 steel. The steel can undergo various heat treatment processes, such as annealing, normalizing, quenching, and tempering, to achieve different levels of strength, toughness, and flexibility. The heat treatment process also helps to refine the steel’s grain structure, eliminate internal stresses, and improve its dimensional stability.


In conclusion, AMS 6349 material is a high-quality alloy with exceptional physical and mechanical properties, hardness, and heat treatability. It is commonly used in critical applications that require exceptional strength, durability, and high-temperature resistance. It has become essential in the aerospace, defence, automotive, and marine industries. Understanding the composition, properties, and uses of AMS 6349 steel is essential in choosing the right material for specific applications and ensuring their optimal performance.

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