Aermet

Aermet special ultra-high strength type of martensiticFact|date=August 2008 steel. The main alloying elements are cobalt and nickel, but chromium, molybdenum, and carbon are also added. Its exceptional properties are hardness, tensile strength, fracture toughness, and ductility.Citation | title = AerMet 100 Alloy | date = 1995-09-01 | url = http://cartech.ides.com/datasheet.aspx?i=103&e=161&c=techart | accessdate = 2008-08-29] Aermet is weldable with no preheating needed. [Citation | title = MIL-HDBK-5H | date = 1998-12-01 | url = http://www.grantadesign.com/userarea/mil/mil5_mainpdf2_5_3.htm | accessdate = 2008-08-30] Aermet is not corrosion resistant so it must be sealed if used in a moist environment. It is a registered trademark of Carpenter Technology Corporation.

There are three types of aermet available: aermet 100 (also known as aermet for tooling), aermet 310, and aermet 340.

Examples of applications include armor, fasteners, airplane landing gear, ordnance, jet engine shafts, structural members, and drive shafts.

Properties

Aermet 100

Aermet 100's UNS number is K92580. The alloy has a modulus of elasticity of 28,200 ksi and a density of 0.285 lbf/in³ (7.89 g/cm³). The materials is somewhat more difficult to machine than 4340 at HRC 38, therefore carbide tools usually used. Standard shapes that are available include: rounds, tubes, sheets, welding wire, billets, plates, strips, and wire.

Aermet is special in that it must be hardened twice in order to reach its maximum effectiveness. The first hardening application is a solution treatment at convert|1625|F|C for 1 hour. It is then quenched to a temperature of convert|150|F|C over 1 to 2 hours. It then must be cold treated, where the material is cooled to convert|-100|F|C for 1 hour. The second hardening process is aging, where the material is is heated to convert|900|F|C for 5 hours.

Aermet 310

Aermet 310 is harder and stronger than aermet 100 while maintaining ductility and toughness. Standard shapes that are available include: rounds, tubes, sheets, wire, billets, plates, and strips. Aermet 310 is hardened the same way that aermet 100 is.

Aermet 340

Aermet 340 has a higher strength than aermet 340.

Aermet 340 is hardened differently than than the other two varieties. The first hardening application is a solution treatment at convert|1775|F|C for 1 hour. It is then quenched to a temperature of convert|150|F|C over 1 to 2 hours. The material may then be cold treated, where the material is cooled to convert|-100|F|C for 1 hour. The second hardening process is aging, where the material is is heated to convert|900|F|C for 3 to 8 hours. If the cold treatment is skipped, the part can be aged twice to get the same results.

References