Threaded Steel Fasteners Threaded Steel Fasteners Threaded Steel Fasteners
THREADED FASTENERS for service between -50 and 200 °C (-65 and 400 °F) can be made from several different
grades of steel, as long as the finished fastener meets the specified strength requirements. This article discusses the
properties of threaded fasteners made from carbon and low-alloy steels containing a maximum of 0.55% C that are
intended for use under the service conditions mentioned above. Guidelines are also discussed for the selection of steels for
bolts (including cap screws), studs (including U-bolts), and nuts for service at the temperature range mentioned above and
for service between 200 and 370 °C (400 and 700 °F). Steels used for threaded fasteners for service above 370 °C (700
°F) are also briefly discussed in this article.

Specification and Selection
Specifications are used to outline fastener requirements, to control the manufacturing process, and to establish functional
or performance standards. Their goal is to ensure that fasteners will be interchangeable, dimensionally and functionally.
The most common fastener specifications are product specifications that are set up to govern and define the quality and
reliability of fasteners before they leave the manufacturer. These specifications determine what material to use; state the
objectives for tensile strength, shear strength, and response to heat treatment; set requirements for environmental
temperature or atmospheric exposure; and define methods for testing and evaluation. To ensure proper use of fasteners,
additional specifications are necessary as a guide to proper design, application and installation. All American Society for
Testing and Materials (ASTM) and Society of Automotive Engineers (SAE) specifications covering threaded fasteners
require that the fastener be marked for grade identification

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