ThePipingMart Blog Grades AMS 5678 Stainless Steel – Composition, Properties and Uses

AMS 5678 Stainless Steel – Composition, Properties and Uses

AMS 5678

AMS5678 is a special material extensively used in various industries. It belongs to the group of corrosion-resistant steel alloys and is known for its exceptional strength, toughness, and resistance to environmental factors. This blog post will examine AMS 5678’s composition, physical and mechanical properties, and industrial applications. Whether you are a materials scientist, a student, or an engineer, this guide will give you a better understanding of AMS5678.

What is AMS 5678?

AMS 5678 (also known as 17-7 PH Stainless Steel) is a specification for high-strength, corrosion-resistant steel alloys. Developed by the Aerospace Materials Specification Committee of SAE International, AMS 5678 sets the standards for these advanced materials’ composition, quality, and performance. With a high nickel content and additional elements like titanium and molybdenum, AMS 5678 alloys offer exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking in harsh environments. These alloys are used in various applications, including aircraft landing gear, rocket motor cases, and marine propulsion systems. By meeting the rigorous requirements of AMS 5678, steel manufacturers can ensure that their products meet the stringent demands of modern aerospace and defence industries.

What Form Is AMS 5678 Available at Piping Mart?

  • Screw

AMS 5678 Composition

AMS 5678 is a steel alloy that contains 20-22% of chromium, 9.0-10.5% of nickel, 2.0-3.0% of molybdenum, and some amounts of manganese, silicon, and carbon. Its composition makes it highly resistant to corrosion, especially in acidic or chlorinated environments. Furthermore, its high nickel and chromium content makes it perfect for harsh environments requiring high strength and toughness.

Element Content (%)
Chromium, Cr 16-18
Nickel, Ni 6.50 – 7.75
Manganese, Mn 1 max
Silicon, Si 1 max
Aluminum, Al 0.75 – 1.50
Carbon, C 0.09 max
Phosphorous, P 0.040 max
Sulfur, S 0.030 max
Iron, Fe Balance

AMS 5678 Physical Properties

AMS 5678 offers exceptional physical properties that make it suitable for heavy-duty applications. Its density is 7.8 g/cm3, and its melting point is around 1350°C. Moreover, it has a coefficient of thermal expansion of 13.7 µm/m°C and a thermal conductivity of 13.1 W/mK.

Properties Metric Imperial
Density 7.80 g/cm3 0.282 lb/in3

AMS 5678 Mechanical Properties

AMS 5678 offers impressive mechanical properties, making it a popular engineering material. Its tensile strength can reach up to 930 MPa, and its yield strength is around 620 MPa. Furthermore, it has a high level of elongation at break, about 20%. These mechanical properties make it ideal for applications that require high strength, durability, and resistance to environmental factors.

Properties Metric Imperial
Tensile strength 1170 MPa 170000 psi
Yield strength 965 MPa 140000 psi
Modulus of elasticity 204 GPa 29600 ksi
Poisson’s ratio 0.27-0.30 0.27-0.30
Elongation at break 6% 6%
Hardness, Rockwell C 38 38

AMS 5678 Equivalent

AISI 631 AMS 5528 AMS 5529 AMS 5568 AMS 5644
AMS 5678 ASTM A313 (631) ASTM A564 (631) ASTM A579 (631) ASTM A693 (631)
ASTM A705 (631) DIN 1.4568 MIL S-25043 DIN 1.4568 AMS 5673
AMS 5824 ASME SA705 ASTM A579 (grade 62) MIL-SPEC MIL-W-46078 SAE J217
SAE J467

AMS 5678 Uses

AMS 5678 has been extensively used across aerospace, automotive, marine, and chemical processing industries. Its high strength, excellent corrosion resistance, and toughness make it ideal for marine applications, pressure vessels, heat exchangers, and chemical processing equipment. Aerospace engineers commonly use it in turbine blades, while automotive industry professionals use it for exhaust systems and engine components.

AMS 5678 Hardness

AMS 5678 has an average hardness value of HRC 25. Its high corrosion resistance, combined with its high toughness, makes it ideal for heavy-duty applications that require high strength and durability.

AMS 5678 Heat treatment

Heat treatment of AMS 5678 screws involves annealing or heating the material above its critical temperature range, followed by quenching in water or oil. This process improves strength, hardness, and toughness, making it a popular material for various applications.


AMS 5678 material is an excellent engineering material with exceptional resistance to environmental factors, high strength, and durability. Its composition, physical and mechanical properties make it ideal for various applications in the aerospace, automotive, marine, and chemical processing industries. Its heat treatment increases its strength and hardness, making it perfect for heavy-duty applications. If you want a strong, durable, and corrosion-resistant material for your next project, consider using AMS 5678. Its impressive properties make it a top choice for engineers and scientists alike.

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