ISSN: 1945-7553
CODEN: JTEVAB
Published Online: 16 November 2007
Page Count: 9

Analytical Determination of the Surface Area of a Threaded Fastener

Rammer, Douglas R.
Research General Engineer and Materials Engineer, U.S.D.A. Forest Service, Forest Products Laboratory, Madison, WI

Zelinka, Samuel L.
Research General Engineer and Materials Engineer, U.S.D.A. Forest Service, Forest Products Laboratory, Madison, WI

(Received 19 September 2006; accepted 3 September 2007)

Abstract

Accurate determination of corrosion rates for threaded fasteners hinges on the ability to determine the surface area on which corrosion is occurring. Currently, no general analytical expression of surface area exists for the threaded fastener types. A recent voluntary withdrawal of chromated copper arsenate as the primary, long-standing preservative treatment for wood resulted in the need to determine the corrosion rates of threaded fasteners. This paper developed general analytical surface area equations for a wedge-shaped thread and the area between the threads for three cases: (1) an increasing thread root and crest diameter, (2) constant thread root and crest diameters, and (3) a constant thread root but a decreasing thread crest diameter. The expressions are applied, numerically verified, and compared to simplified models for a No. 10–2.54 cm (1-in.) long wood screw.

Keywords:
corrosion, analytical, fastener, screw, surface area

Paper ID: JTE100806
DOI: 10.1520/JTE100806
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