ASTM A394 is a standard material specification covering 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 specification includes type 0, type 1 and type 3 structural bolts in carbon, alloy and weathering steel with plain and coated surfaces.

Find classification of grades, chemical composition, mechanical properties, shear strength, marking, recommended nuts, surface finish or coating and other reference standards for ASTM A394 Bolts.

Grade Classification

Grade	Raw Material Description
Type 0	Low or medium carbon steel.
Type 1	Medium carbon steel, quenched and tempered.
Type 3	Weathering steel, quenched and tempered.

Chemical Composition

Element	Grade
	Type 0	Type 1	Type 3 (Class C)
Carbon	0.55 max	0.28 – 0.55	0.15 – 0.25
Manganese, max	...	0.60 min	0.80 – 1.35
Phosphorus, max	0.048 max	0.048 max	0.035 max
Sulfur, max	0.058 max	0.058 max	0.040 max
Silicon	...	...	0.15 – 0.35
Copper	...	...	0.20 – 0.50
Nickel	...	...	0.25 – 0.50
Chromium	...	...	0.30 – 0.50
Vanadium	...	...	0.02 min

Mechanical Properties

Nominal size, Inch.	Minimum Tensile Load, lbf		Hardness
	Type 0	Type 1 and 3	Type 0	Type 1 and 3
1/2	10 500	17 050	80 – 100 Rockwell B	25 – 34 Rockwell C
5/8	16 700	27 100
3/4	24 700	40 100
7/8	34 200	55 450
1	44 850	72 700

Recommended Nuts and Coating

Grade	Nut Grade	Coating
Type 0	A563 Grade A	Hot Dip or Zinc Coating
Type 1	A563 Grade DH	Hot Dip or Zinc Coating
Type 3	A563 Grade DH3	Plain

Reference Standards

ASTM A563	Specification for Carbon and Alloy Steel Nuts
ASTM F436	Specification for Hardened Steel Washers
ASTM F2329	Specification for Zinc Coating, Hot-Dip
ASME B1.1	Unified Screw Threads
ASME B18.2.1	Square and Hex Bolts and Screws