American Belleville’s Flange Washer line adds deflection to bolted joints, in order to dramatically reduce the effects of large fluctuations in temperature within the application, vibration, bolt creep (stretch), gasket creep, or relaxation, and other elastic interactions within the joint. They may be flattened, without losing operating preload, except in cases where dynamic cycling occurs. Typically, at least two American Belleville Flange Washers will be used in a single bolted assembly, with one on either end of the bolt. The ID, on the convex side of the washer should contact the underside of the bolt head and the nut. The OD edge on the concave side of the washer should always contact the flange surface.
American Belleville Flange Washers can be specified by identifying a few characteristics of the application, starting with bolt diameter and bolt stress; the latter calling out either 30,000 psi, 45,000 psi or 60,000 psi. They can be utilized in either inch or metric applications, and are typically made using three different raw material options:
- H13 Tool Steel (ASTM A681) for refining and chemical flange bolting applications with temperatures reaching over 1000 deg. F, where corrosion resistance is not crucial, but high strength is. This material is fully magnetic.
- 17/7PH Stainless Steel (ASTM A693) for refining and chemical flange bolting applications reaching 500 deg. F, and where high strength and corrosion resistance is needed. This material is highly magnetic.
- Inconel 718 (ASTM B670 / AMS 5596) for flange bolting applications reaching over 1000 deg. F. This material is highly corrosion resistant, offers good strength properties and is non-magnetic.
Traditional applications for American Belleville Flange Washers include:
- Pipe Flanges
- Heat Exchangers
Low temperature applications (Cryogenic) can also utilize American Belleville Flange Washers