High Temperature Joint Fastening Considerations and Solutions

High Temperature Joint Fastening Considerations and Solutions

In automotive and industrial engine applications, high temperature joints are those joints in the exhaust system which include the exhaust manifold, turbocharger, heat shield, EGR (Exhaust Gas Recirculation), SCR (Selective Catalytic Reduction), and catalytic convertor attachment points.

In applications where the temperatures exceed the capability for that of carbon steel or carbon alloy fasteners, the use of a high temperature-stable material will be required. The majority of fasteners used in automotive and industrial vehicle manufacturing are carbon alloy varieties which are typically property class 8.8 or 10.9 heat treated materials (grade 5 or 8 for inch size). These materials are heat treated with a quench and temper process which fall into the 370-425°C (700-800°F) tempering range. The mechanical capability of these materials begins to diminish in operating temperatures above this range. The fasteners may begin to anneal or soften which will result in clamp load loss or failure.

Most solid joints designed for ambient temperatures are typically very predictable based on mathematical formulations for torque versus load, mechanical strength of the fastener, and external forces exerted on the joint; but high temperature applications do not behave similarly. Designing fasteners for high temperature joints can be a difficult task due to the vast number of variables involved. The effects of carbon monoxide, hydrocarbons, nitrogen oxides, water vapor, cyclic vibration and high temperature all contribute to the complexity of designing a system that provides long-term durability and performance in an economical way.

Because these temperatures wreak so much havoc on joints, causing bolts to loosen and clamp loads to be lost, the experts at MacLean Maynard, a division of MacLean Fogg Component Solutions, have designed products that hold up in these extreme environments.  These products include fasteners manufactured from A286, Nimonic (TM) 80A, Inconel (TM) 718 and other exotic materials.  For those high temperature and high vibration applications like engine exhausts and turbo chargers, the top OEMs turn to our High Temperature Bolts and Studs.

The team at MacLean-Fogg Component Solutions are ready to help with your fastener engineering needs.  Have comments, questions or feedback regarding this paper, please feel free to contact us by clicking here.

Related Products





Thursday, March 10, 2016

General Motors Recognizes MacLean-Fogg Component Solutions as a 2015 Supplier of the Year Winner

MacLean-Fogg Component Solutions was named a GM Supplier of the Year by General Motors during its 24th annual Supplier of the Year awards ceremony held Thursday, March 10 at Cobo Center in Detroit, Michigan. General Motors recognized 110 of its best suppliers from 17 countries that have consistently exceeded GM’s expectations, created outstanding value, or brought new innovations to the company. This is the first time in MacLean-Fogg Component Solutions’ history we have received this award. » Continue Reading

Tuesday, July 28, 2015

MFCS Celebrates Three Anniversaries

2015 is a milestone year for Mac-Lean Fogg Company. Not only is the company as a whole celebrating its 90th year in business, but MacLean-Fogg Component Solutions, a division of MacLean-Fogg Company, is also celebrating significant anniversaries in three of its own divisions. » Continue Reading