ThePipingMart Blog Grades AMS 6390 Alloy Steel – Composition, Properties, and Uses

AMS 6390 Alloy Steel – Composition, Properties, and Uses

AMS 6390

AMS 6390 is a type of steel known for its exceptional strength and durability. It is primarily used in high-stress applications requiring maximum strength and toughness. But what exactly is SAE – AMS 6390? This blog post will explore the composition, physical and mechanical properties, and uses of AMS 6390 steel.

What is AMS 6390?

AMS 6390 (also known as SAE-AISI 4140 Alloy Steel) is a specification for alloy steel used in aircraft and defense industries. This high-strength steel has excellent toughness and fatigue resistance, making it a popular choice for critical components such as landing gear, engine mounts, and weapon systems. AMS6390 undergoes strict testing to ensure it meets the mechanical properties required for these applications. Whether standing up to extreme temperatures or enduring repetitive stress, AMS 6390 material has built a reputation as a reliable and durable material for some of the toughest jobs.

What Form is AMS 6390 Available at Piping Mart?

  • Alloy Steel AISI 4140 Bars

AMS 6390 Composition

AMS 6390 sheet is a low-alloy steel composed primarily of iron, carbon, and manganese. It also includes other alloying elements, such as nickel, chromium, and molybdenum, contributing to its high strength and toughness. The exact composition of AMS6390 can vary depending on the manufacturer, but it typically contains between 0.25% and 0.35% carbon, 0.60% to 0.90% manganese, 0.35% to 0.70% silicon, and 0.20% to 0.40% molybdenum.

Element Content (%)
Iron, Fe 96.785 – 97.77
Chromium, Cr 0.80 – 1.10
Manganese, Mn 0.75 – 1.0
Carbon, C 0.380 – 0.430
Silicon, Si 0.15 – 0.30
Molybdenum, Mo 0.15 – 0.25
Sulfur, S 0.040

Phosphorous, P


AMS 6390 Physical Properties

AMS 6390 has a density of 7.85 g/cm3 and a melting point of 1425°C (2600°F). It is a challenging and ductile steel that can withstand various temperature variations. It also exhibits excellent corrosion resistance and can be used in harsh environments without corroding or degrading over time.

Properties Metric Imperial
Density 7.85 g/cm3 0.284 lb/in³
Melting point 1416°C 2580°F

AMS 6390 Mechanical Properties

AMS 6390 plate is known for its exceptional tensile strength and toughness. It has a yield strength of 1034 MPa (150,000 psi), a tensile strength of 1207 MPa (175,000 psi), and an elongation of 13%. It has good fatigue resistance and can withstand repeated stress cycles without breaking or cracking.

Properties Metric Imperial
Tensile strength 655 MPa 95000 psi
Yield strength 415 MPa 60200 psi
Bulk modulus (typical for steel) 140 GPa 20300 ksi
Shear modulus (typical for steel) 80 GPa 11600 ksi
Elastic modulus 190-210 GPa 27557-30458 ksi
Poisson’s ratio 0.27-0.30 0.27-0.30
Elongation at break (in 50 mm) 25.70% 25.70%
Hardness, Brinell 197 197
Hardness, Knoop (converted from Brinell hardness) 219 219
Hardness, Rockwell B (converted from Brinell hardness) 92 92
Hardness, Rockwell C (converted from Brinell hardness. Value below normal HRC range, for comparison purposes only) 13 13
Hardness, Vickers (converted from Brinell hardness) 207 207
Machinability (based on AISI 1212 as 100 machinability) 65 65

AMS 6390 Equivalent

AMS 6349 ASTM A193 (B7, B7M) ASTM A506 (4140) ASTM A752 (4140)
AMS 6381 ASTM A194 (7, 7M) ASTM A513 ASTM A829
AMS 6382 ASTM A29 (4140) ASTM A513 (4140) SAE J1397 (4140)
AMS 6390 ASTM A320 (L7, L7M, L7D) ASTM A519 (4140) SAE J404 (4140)
AMS 6395 ASTM A322 (4140) ASTM A646 (4140) SAE J412 (4140)
AMS 6529 ASTM A331 (4140) ASTM A711

AMS 6390 Uses

AMS 6390 wire is commonly used in high-stress applications such as gears, shafts, and other mechanical components. It is also used in aerospace for parts such as landing gear struts and engine mounts. In the automotive industry, it is used for drivetrains codrivetrainuch as axles and drive shafts. AMS6390 is also used in oil and gas for drilling equipment and other high-stress applications.

AMS 6390 Hardness

AMS 6390 has a hardness range of 341 to 388 HB (Brinell hardness). This high hardness makes it ideal for applications requiring maximum strength and durability.

AMS 6390 Heat Treatment

AMS 6390 wire can be heat-treated to achieve the desired strength and hardness. It is typically quenched and tempered to achieve a 341-388 HB hardness. The heat treatment process can also improve its toughness and flexibility.


AMS 6390 steel is a high-strength, low-alloy steel that offers exceptional strength, toughness, and durability. It is used in many applications requiring maximum strength, including gears, shafts, landing gear struts, and drivetrain drivetrains. Excellent physical and mechanical properties and corrosion resistance make it popular in the aerospace, automotive, and oil and gas industries. With its high hardness and ability to be heat-treated, AMS 6390 material is a reliable choice for any high-stress application.

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