Machinery's Handbook, 31st Edition
1702
Fasteners for Structural Applications Fasteners for Use in Structural Applications
The ANSI/ASME B18.2.6 standard covers the complete general and dimensional data for four products in the inch series recognized as American National Standard. Heavy hex nut thickness formulas and those for width across flats and width across corners are found in the Appendix of ANSI/ASME B18.2.2. The inclusion of dimensional data in this standard is not intended to imply that all products described herein are stock production sizes. Fasteners intended for use in structural applications and purchased for government use shall conform to this standard. All dimensions in ANSI/ASME B18.2.6 are in inches unless stated otherwise, and apply to unplated or uncoated product. Symbols specifying geometric characteristics are in accord with ASME Y14.5, Dimen- sioning and Tolerancing . Standards for chemical and mechanical requirements for struc- tural bolts are included in ASTM A325 and ASTM A490. Heavy hex nuts are included in ASTM A563. Hardened steel washers are included in ASTM F436, and compressible washer type direct tension indicators in ASTM F 959. Heavy Hex Structural Bolts.— Head Width Across Flats: The width across flats of heads shall be the distance measured perpendicular to the axis of product, overall between two opposite sides of the head in accordance with the notes in the dimensional table. Head Height: The head height shall be that overall distance measured parallel to the axis of the product from the top of the head to the bearing surface and shall include the thickness of the washer face. Raised grade and manufacturer’s identification are excluded from head height. Bolt Length: The bolt length shall be the distance measured parallel to the axis of the product from the bearing surface of the head to the extreme end of the bolt including point. Threads: Threads shall be cut or rolled in accordance with ASME B 1.1. When specified, 8 thread series may be used on bolts over 1 inch in diameter. Structural bolts shall not be undersized to accommodate heavy coatings. Threads which have been hot-dipped or mechanically zinc coated shall meet the requirements specified in ASTM A325. Body Diameter: The body diameter limits are shown in Table 5. Finish: Unless otherwise specified, bolts shall be supplied with a plain (as processed) finish. Bolts to ASTM A490 shall not be metallic coated. Materials: Chemical and mechanical properties of steel bolts shall conform to ASTM A325 or ASTM A490. Workmanship: Bolts shall be free from burrs, seams, laps, loose scale, irregular surfaces, and any defects affecting serviceability. When control of surface discontinuities is required, the purchaser shall specify conformance to ASTM F 788/F 788M, surface discontinuities of bolts, screws, and studs, inch and metric series. Designation: Heavy hex structural bolts shall be designated by the following data in the sequence shown: product name, nominal size (fractional or decimal equivalent), threads per inch, material (including specification and type where necessary), and protective zinc coated. Identification Grade Symbols: Each bolt shall be marked in accordance with the require ments of the applicable specification; ASTM A325 or ASTM A490 and requirements of Table 5 , Note (13). finish (if required). See example below: Example: Heavy Hex Structural Bolt, 3 ∕ 4 -10 × 2 1 ∕ 4 , ASTM A325, Type 1, hot dipped
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online