A Fe-Ni-Cr alloy with excellent high temperature oxidation resistance
- Good material for high temperature oxidation resistance
- Maintains high strength at elevated temperatures
- A286 Chemistry, specs, and heat treatments
- A286 Torx screw features and benefits
A-286 Torx screws are known for their high strength, creep resistance and oxidation resistance at elevated temperatures. This iron-nickel-chromium alloy (once age-hardened) provides A-286 Torx screws with high levels of strength from room temperature up to about 1300°F (700°C).
A-286 screws are mildly corrosion resistant. While they should not be used for strong acid environments, they provide excellent oxidation resistance up to 1300°F (700°C) in conditions that would typically be found in high temperature exhaust streams.
Because of these properties, A-286 Torx screws are often found in high temperature engine, manifold, exhaust and turbine applications as well as off-shore oil & gas applications.
Resources: A-286 Torque Specs
A286 Torx screws are characterized by a 6-point star-shaped pattern, also called a star drive, spined socket or hexalobular (ISO 10664). Where Phillips heads were designed to cause the driver to cam-out (prevent overtightening), Torx screws were designed resist cam-out. This feature allows A286 Torx screws to provide increased torque as well as better torque transfer between driver and fasteners. This feature also helps to reduce wear on driver bits.
A286 Torx Screw Advantages
- Resistant to cam out (process by which a screwdriver slips out of the head)
- A286 Torx screws are more difficult to strip
- Increased tamper resistance as a star driver isn’t as common
- Driver insert is less susceptible to damage when over torqued than Allen head
A-286 Heat Treatments: There are several heat treatment combinations for A-286 all with slight variations in performance. They can be specified via an AMS number or a 660 Class: A, B, C or D, with most common specified as class A or D. The A-286 grades A, B and C all have the same min tensile strength and min yield strength of 130ksi and 85ksi respectively. However grade D is significantly better yield with a min tensile of 130ksi and a min yield of 105ksi.
By AMS numbers, the most common for A-286 is AMS 5737 (same as Grade A) and then AMS 5732 (same as Grade B).
A-286 Specifications: AMS 5525, AMS 5732, AMS 5737, AMS 5804, EN 1.4980, GE B50T1181, GE B50T12, GE B50T81, UNS S66286, Werkstoff 1.4980