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 – Zinc coated bolts made of low or medium carbon steel.
1.1.2 Type 1 – Zinc coated bolts made of medium carbon steel, quenched and tempered.
1.1.3 Type 2 – Zinc coated bolts made from what is generally described as low carbon martensite
steel, quenched and tempered.
1.1.4 Type 3 – Bare (uncoated), quenched and tempered bolts made of steel having atmospheric
corrosion-resistance and weathering characteristics comparable to that of the steel covered in Specifications ASTM A242/A242M, A588/A588M, and A709/A709M. The atmospheric corrosion resistance of these steels is substantially better than that of carbon steel with or without copper addition (see 5.4). When properly exposed to the atmosphere, these steels can be used bare (uncoated) for many applications.
1.1.5 For applications requiring improved low temperature characteristics, use of Types 1, 2, or 3 bolts is recommended.