High Temperature Fasteners for Exhaust and Turbo Systems

Selecting high temperature fasteners for exhaust and turbo systems involves more than picking an alloy from a table. The right choice depends on where in the system the fastener sits, what temperature the fastener metal actually reaches, and whether the joint needs to hold clamp load against vibration as well as heat.

Key Takeaways:

• Selecting the right high-temperature fastener depends on confirmed fastener metal temperature at the shank, not exhaust gas or surface temperature. The difference can determine whether A286, Inconel 718, or Nimonic 80A is the correct alloy.
• Conventional locking methods, like nylon inserts, anaerobic adhesives, and prevailing torque nuts, fail well below exhaust operating temperatures.
• Lockthread's mechanical tri-lobular design has no thermal ceiling, making it the appropriate locking solution for exhaust and turbo joints.
• A $0.50 fastener can take a $1,000,000 machine offline. Specifying the right alloy from the start is almost always cheaper than engineering around failure after the fact.

High Temperature Fastener Range at a Glance

Five alloy families are available, from A286 for exhaust manifold and EGR service through Nimonic 80A for extreme-duty turbocharger applications.