【国外标准】 Standard Specification for Steel Transmission Tower Bolts, Zinc-Coated and Bare

This specification covers the chemical and mechanical requirements of hexagon and square-head zinc-coated steel bolts and atmospheric corrosion-resistant bolts for use in the construction of transmission towers, substations, and similar steel structures. The following types of bolts are: Type 0 includes hot-dip zinc-coated bolts made of low or medium carbon steel, Type 1 includes hot-dip zinc-coated bolts made of medium carbon steel, quenched and tempered, Type 2, and Type 3 includes bare, quenched, and tempered bolts made of weathering steel. Steel for the manufacture of bolts shall be made by any of the following processes: open-hearth, electric-furnace, or basic-oxygen. Type 1 bolts produced from medium carbon steel shall be quenched in a liquid medium from above the austenizing temperature. Type 1 bolts produced from medium carbon steel to which chromium, nickel, molybdenum, or boron were intentionally added shall be quenched only in oil from above the austenitizing temperature. Type 3 bolts shall be quenched only in oil from above the austenitizing temperature. Cold-headed Type 0 bolts shall be stress relief annealed before zinc coating to remove cold work effects such that the hardness measured anywhere on the surface or through the cross-section shall meet the requirement specified. Different tests shall be conducted in order to determine the following mechanical properties of bolts: hardness, tensile strength, and shear strength.1.1 This specification covers the chemical and mechanical requirements of hexagon and square-head zinc-coated steel bolts and atmospheric corrosion-resistant bolts, in nominal thread diameters of 1/2 , 5/8 , 3/4 , 7/8 and 1 in. for use in the construction of transmission towers, substations, and similar steel structures. The various types of bolts covered in this specification are:1.1.1 Type 0—Hot-dip zinc-coated bolts made of low or medium carbon steel.1.1.2 Type 1—Hot-dip zinc-coated bolts made of medium carbon steel, quenched and tempered.1.1.3 Type 2—Withdrawn in 2005.1.1.4 Type 3—Bare (uncoated), quenched and tempered bolts made of weathering steel.1.2 Annex A1 of this specification covers hot-dip zinc-coated steel ladder bolts, step bolts, and support-equipment bolts.1.3 Nuts and washers that are supplied under this specification that are hot-dip zinc coated shall be in accordance with 4.4.1.4 Terms used in this specification are defined in Terminology F1789.1.5 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.1.6 The following safety hazards caveat pertains only to the test methods portion, Section 11, of this specification. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.