ASTM A394 TOWER BOLTS is standard of bolts use in the construction of transmission towers, substations,
and similar steel structures. There are 3 types: 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,
eletric-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.
Recommended Nuts for ASTM A394 TOWER BOLTS
Unless otherwise specified, all nuts on these bolts shall be hex style and conform to the requirements of
Specification A 563 as follows.
Bolt Type Nut Grade Finish
0 A hot-dip zinc-coated
1 DH hot-dip zinc-coated
3 DH3 plain
Recommended Washers for ASTM A394 TOWER BOLTS
Suitable washers for use with Type 0 are hot-dip zinc-coated carbon-steel washers with dimensions that are
in accordance with Specification F436. Suitable washers for use with Type 1 bolts are hot-dip zinc-coated
Type 1 hardened-steel washers that are in accordance with Specification F436.
Suitable washers for use with Type 3 bolts are Type 3 hardened-steel washers that are in accordance with
Specification
Materials and Manufacture of ASTM A394 TOWER BOLTS
Steel for the manufacture of bolts shall be made by any of the following processes: open-hearth,
electric-furnace, or basic-oxygen.
Heat Treatment of of ASTM A394 TOWER BOLTS
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.
Zinc Coatings, Hot Dip of ASTM A394 TOWER BOLTS
Type 0 and Type 1 bolts shall be hot-dip zinc-coated accordance with the requirements of Specification
A 153/ A 153M, except that the minimum average weight (thickness) of zinc coating shall be 1.65 oz/ft2
(0.0028 in.) and the minimum weight of zinc coating on any one item shall be 1.50 oz/ft2 (0.0025 in.).
