A Fe-Ni-Cr alloy with excellent high temperature oxidation resistance

Hex head cap screws made from A-286 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 hex head cap screws with high levels of strength from room temperature up to about 1300°F (700°C).

A-286 hex head cap 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 hex head cap 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

Screw Types12 Point ScrewsButton Head Cap ScrewsFlat Head ScrewsHex Cap ScrewsPan Head ScrewsSet ScrewsSocket Head Cap ScrewsTorx ScrewsVented Screws


A-286 Hex Head Cap Screw Features and Benefits

It is important to differentiate between a A-286 hex head cap screw and hex head bolt. Often people assume they are the same, but they are actually very different fasteners in terms of how they are manufactured, as well as from an application perspective. Regardless of your choice, A-286 hex heads offer strong, stable joints because of their large head service.

The Hex Comparison

Hex Head Cap Screw Hex Head Bolts
  • Precise applications where tight tolerances on the body dimensions are required. 
  • Features flat washer facing under the bolt head.
  • Also called a finished hex bolt.
  • Appropriate for when mechanical properties are more important than dimensional tolerances. 
  • Hex bolts have a flat end and lack the washer face under the head.

A-286 Hex Head Cap Screw Advantages  

The most important feature of a A-286 hex head cap screws is that it has a larger bearing surface area which provide better clamping pressure than other type of fastener such as a socket head cap screw. Additionally, since debris build up is less of an issue with this style of fastener verses a socket head cap screw, they are ideal of dirty applications where particles could clog up a socket. Though A-286 socket heads are typically used for tight access applications, hex heads can be a better choice when there is only side clearance available for tightening. 

 


A-286 Chemistry, Specifications & Heat Treatments

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

A 286 Chemistry


Mechanical Properties

A-286 Tensile Curves

 

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