Document Center Inc. The following bibliographic material is provided to assist you with your purchasing decision: This specification covers two types of heat treated, steel, tension control bolt-nut washer assemblies. An assembly consists of a tension control bolt with spline end and a suitable nut and washer. These assemblies are capable of developing a minimum predetermined tension when installed by applying torque to the nut, while at the same time applying a counter torque to separate the spline end from the body of the bolt using an appropriate spline drive installation tool.
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What are F and F? Their twist-off type counterparts are F and F, respectively Figure 1. Generally, bolt standards are introduced when new products become available and the demand exists. All six standards include many provisions that are common to two or more standards as well as provisions that are unique to one. Recently, ASTM saw the need and opportunity to streamline the process and moved to consolidate these standards. The consolidation aims to simplify revisions in the future.
It may also enhance user-friendliness by eliminating duplication of provisions that are common to all bolt grades, types, styles, etc. Unlike other bolt standards, F was not issued to cover a new product. In this umbrella standard, the name of each bolt standard becomes a bolt grade e. A becomes F Grade A The traditional bolt type designations remain i. Type 3 for weathering steel and Type 1 for bolts of other high-strength steel compositions. All bolts manufactured after the publication date of F in January must comply with the marking requirements of F In an attempt to orchestrate a smooth transition, bolt head markings remain essentially unchanged, as shown in Figure 2.
In addition, technical changes have been kept to the minimum. This change unifies the unit tensile strength level for these bolts irrespective of diameter. Other changes include an addition of ductility requirements for twist-off style bolts, more detailed rotational capacity test requirements, and an annex for coatings.
The above-mentioned increase in tensile strength generally affects the design of connections having large diameter A and F bolts. These bolts are not commonly used in construction of buildings and bridges although users may resort to A bolts when strong galvanized bolts are required A and F bolts should not be galvanized or plated and F bolts should be not be hot-dip galvanized.
Both the tensile and shear resistance of these bolts increase with the tensile strength increase. The slip resistance for a given class of contact surface and installation method increases with the pretensioned force, which is proportional to the ultimate tensile strength. Ignoring the strength increase in large A and F bolts is a safe and conservative interim solution.
Therefore, the strength increase in large A and F bolts does not affect designs in accordance with S Hence the strength increase may be accounted for in the design when use of bolts manufactured to F is confirmed whereas ignoring the higher strength is a safe and conservative interim solution.
ASTM F3125 – A New Bolt Standard