Q: I’m designing a furnace vent system for a continuous service high heat appliance (NFPA 211). The maximum furnace working temperature is 2100 deg F; design temperature is 2190 deg F. Will Alloy 330 or 310 SS bolts and nuts work for me?

A: You are at the absolute limit in terms of temperature for these fasteners for 310 or 330. (see https://www.extreme-bolt.com/applications-high-temperature.html).  To determine if the fasteners will work in your application you need to understand the load that is required on each fastener.  At those high temperatures, the fasteners will be weak so you must be careful about what is needed from a strength point of view.  You might want to also consider Inconel 600.

From thermal processing and furnace applications to the extreme demands of aerospace, several high temperature alloys are available each with unique traits and capabilities. This brief newsletter will outline the primary fastener materials that are commonly used for excellent high temperature and oxidation resistance.

Best High Temperature Oxidation Resistant Fasteners

ALLOY 330
Developed for furnace applications, Alloy 330 fasteners are ideal for high temperature oxidation and caburization resistance. They are one of few materials that can handle extreme temperature changes, plus alternate carburizing and oxidizing atmospheres. KEY TRAIT: Performance under cyclic heating &  cooling

INCONEL 625
Inconel 625 bolts deliver a unique package of corrosion, oxidation and carburization resistance combined with high temperature strength. Their nickel and chromium content provides resistance to a many of harsh chemicals including sulfuric acid. KEY TRAIT: Great high temp stability &  strength, in   even in corrosive environments

WASPALOY
Fasteners made from this unique alloy offer extreme temperature and oxidation resistance in combination with high strength. Waspaloy is one of the strongest fasteners available for use over 1300°F. KEY TRAIT: Extreme strength at high temperatures

A286 / ALLOY 660
Age hardened, Alloy 660 / A286 fasteners offer good oxidation and creep resistance, as well as high temperature strength. They are most commonly used in high temperature exhaust streams. KEY TRAIT: Very good strength at high temperatures

310SS
Offering good strength under mildly cyclic conditions. Alloy 310 fasteners also offer good resistance to oxidation, carburization, and other forms of hot corrosion. KEY TRAIT: Economic high temperature alloy for moderate strength applications