AMS 5698 Haynes Alloy – Composition, Properties, and Uses
With the increasing demand for high-performance alloys in various industries, metallurgists continuously develop advanced materials that can withstand extreme temperatures and harsh environments. AMS5698 is one of these alloys that gained recognition for its remarkable properties, making it an ideal material for aerospace, chemical processing, and other industries. This blog post will dig deeper into AMS5698’s composition, physical properties, mechanical properties, uses, hardness, and heat treatment.
What is AMS 5698?
AMS 5698 (also known as Haynes X-750) is a steel alloy commonly used in the aerospace and defence industries due to its high strength and durability. It’s also used in medical implants and surgical instruments because of its biocompatibility. AMS 5698 is a prime example of how science and technology can work hand in hand to create materials that are both strong and safe for human use.
AMS 5698 Composition
AMS 5698 is a precipitation-hardening stainless steel alloy with a unique composition and properties. Its standardized composition includes 15.5-17.5% chromium, 7-9% nickel, 1.5-2.5% molybdenum, 0.08% carbon, 1% manganese, 0.1% silicon, 0.03% phosphorus, and 0.03% sulfur. The alloy also has a low ferrite content and a high level of gamma prime, a complex and stable intermetallic compound found in its microstructure. The presence of the gamma prime phase makes AMS 5698 highly resistant to corrosion, oxidation, and wear.
| Element | Content (%) |
|---|---|
| Chromium, Cr | 14-17 |
| Iron, Fe | 5-9 |
| Titanium, Ti | 2.25-2.75 |
| Manganese, Mn | 1 max |
| Niobium, Nb | 0.7-1.2 |
| Copper, Cu | 0.5 max |
| Silicon, Si | 0.5 max |
| Aluminum, Al | 0.4-1 |
| Carbon, C | 0.08 max |
| Sulfur, S | 0.01 min |
| Nickel, Ni | Remainder |
AMS 5698 Physical Properties
AMS 5698 is a high-strength, high-temperature material with excellent physical properties. It has a density of 7.8 g/cm3, a melting point of 1430-1455°C, and thermal conductivity of 16.3 W/m-K at 100°C. The alloy can maintain its strength up to 800°F (427°C) and has a coefficient of thermal expansion of 10.1 µm/m-°C. Its thermal and electrical conductivity properties are lower than those of austenitic stainless steels, making it ideal for high-temperature, low-conductivity applications.
| Properties | Metric | Imperial |
|---|---|---|
| Density | 8.26 g/cm³ | 0.298 lb/in³ |
| Melting point | 1413°C | 2575°F |
AMS 5698 Mechanical Properties
AMS 5698 has exceptional mechanical properties, making it a popular material for high-stress applications. The alloy has a tensile strength of 185 ksi (1275 MPa) and a yield strength of 165 ksi (1138 MPa). Its elongation at break is 10%, and its hardness is 37 HRC. AMS 5698 also has excellent fatigue resistance and toughness, making it ideal for critical aerospace and chemical processing applications.
| Properties | Metric | Imperial |
|---|---|---|
| Tensile strength | 1325 MPa | 192.2 ksi |
| Elongation at break (in 51 mm) | 23.60% | 23.60% |
| Reduction of area | 42% | 42% |
AMS 5698 Equivalent
| AISI 688 | AMS 5598 | AMS 5670 | AMS 5747 | GE B50TF1232 |
| AMS 5542 | AMS 5667 | AMS 5671 | ASTM B637 | GE B50YP44 |
| AMS 5582 | AMS 5668 | AMS 5698 | DIN 2.4669 | MIL N-24114 |
| AMS 5583 | AMS 5669 | AMS 5699 | DIN 2.4699 | MIL N-7786 |
AMS 5698 Uses
AMS 5698 is valuable for various industrial sectors due to its unique properties and superior performance under extreme conditions. The alloy is commonly used in aircraft and missile parts, cryogenic systems, turbine engine components, and chemical processing equipment. Its excellent corrosion resistance suits marine applications such as pumps, valves, and heat exchangers. AMS 5698 is also an ideal material for downhole tools like pumps, valves, and other equipment used in the oil and gas industry.
AMS 5698 Hardness
AMS 5698 has a hardness of 37 HRC in precipitation-hardened conditions. The alloy can be further strengthened by cold working and age-hardening processes. Cold-working the material increases its strength and hardness, while age-hardening increases its tensile and yield strength and improves its toughness. AMS 5698 exhibits exceptional dimensional stability after hardening and is less likely to deform or crack.
AMS 5698 Heat Treatment
The heat treatment process for AMS 5698 is essential for achieving the required mechanical properties. The alloy is solution-treated at 1010-1135°C, quenched in water or oil, and then aged at 621-788°C to induce precipitation hardening. The ageing process can take up to 8 hours, depending on the desired strength and hardness. Cold working the material before heat treatment enhances its response to ageing. Proper heat treatment and processing of AMS 5698 are critical to yield excellent mechanical properties and performance under harsh conditions.
Conclusion:
AMS 5698 material is a special alloy with unique composition, properties, and applications. Its exceptional corrosion, oxidation, and wear resistance make it an ideal material for various industries such as aerospace, chemical processing, and oil and gas. The alloy’s hardness, mechanical strength, and heat treatment properties make it an excellent choice for critical applications where dimensional stability and toughness are vital. Understanding the composition and properties of AMS 5698 is crucial for selecting a suitable material for a particular application. With proper heat treatment and processing, AMS 5698 can deliver reliable, long-lasting performance, even under extreme conditions.
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