ASTM A394 Bolting Specification

Structural & Transmission Tower Bolts

ASTM A394 Hex Bolts, Square Bolts, Tower Bolts & Nuts

ASTM A394 Tower Bolts & Nuts both 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 inch are used in the construction of transmission towers, substations, and similar steel structures. Type 0 and Type 1 bolts shall be hot-dip zinc-coated accordance with the requirements of Specification F2329, 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/ft 2 (0.0025 in.).When non-zinc-coated atmospheric corrosion- resistant steel is required, Type 3 bolts shall be specified by the purchaser. ASTM A394 Type 0 Ladder bolts, step bolts, and equipment support bolts are also Manufactured at TorqBolt.

Scope

Bolt Type	Nut Grade	Finish
ASTM A394 Grade 0	A	hot-dip zinc-coated
ASTM A394 Grade 1	DH	hot-dip zinc-coated
ASTM A394 Grade 3	Dh4	plain

ASTM A394 Chemical requirements

Element	Analysis	Bolts Types
		Type 0 BoltsA	Type 1 BoltsA	Type 3 BoltsA
			A	B	C	D	E	F
C	Heat Analysis	0.55 max	0.28/0.55	0.33-0.40	0.38-0.48	0.15-0.25	0.15-0.25	0.20-0.25	0.20-0.25
	Product Analysis	. . .	. . .	0.31-0.42	0.36-0.50	0.14-0.26	0.14-0.26	0.18-0.27	0.19-0.26
Mn	Heat Analysis	. . .	0.60 min	0.90-1.20	0.70-0.90	0.80-1.35	0.40-1.20	0.60-1.00	0.90-1.20
	Product Analysis	. . .	. . .	0.86-1.24	0.67-0.93	0.76-1.39	0.36-1.24	0.56-1.04	0.86-1.24
P	Heat Analysis	0.048 max	0.048 max	0.035 max	0.06-0.125	0.035 max	0.035 max	0.035 max	0.035 max
	Product Analysis			0.040 max	0.06-1.25	0.040 max	0.040 max	0.040 max	0.040 max
B	Heat Analysis	..	…	…	…	…	…	…	…
	Product Analysis	..	…	…	…	…	…	…	…
S	Heat Analysis	0.058 max	0.058 max	0.040 max	0.040 max	0.040 max	0.040 max	0.040 max	0.040 max
	Product Analysis	..	…	0.045 max	0.045 max	0.045 max	0.045 max	0.045 max	0.045 max
Si	Heat Analysis	..	…	0.15-0.35	0.30-0.50	0.15-0.35	0.25-0.50	0.15-0.35	0.15-0.35
	Product Analysis	..	…	0.13-0.37	0.25-0.55	0.13-0.37	0.20-0.55	0.13-0.37	0.13-0.37
Cu	Heat Analysis	..	…	0.25-0.45	0.20-0.40	0.20-0.50	0.30-0.50	0.30-0.60	0.20-0.40
	Product Analysis	..	…	0.22-0.48	0.17-0.43	0.17-0.53	0.27-0.53	0.27-0.63	0.17-0.43
Ni	Heat Analysis	..	…	0.25-0.45	0.50-0.80	0.25-0.50	0.50-0.80	0.30-0.60	0.20-0.40
	Product Analysis	..	…	0.22-0.48	0.47-0.83	0.22-0.53	0.47-0.83	0.27-0.63	0.17-0.43
Cr	Heat Analysis	..	…	0.45-0.65	0.50-0.75	0.30-0.50	0.50-1.00	0.60-0.90	0.45-0.65
	Product Analysis	..	…	0.42-0.68	0.47-0.83	0.27-0.53	0.45-1.05	0.55-0.95	0.42-0.68
V	Heat Analysis	..	…	B	B	0.020 min	B	B	B
	Product Analysis	..	…	B	B	0.010 min	B	B	B
Mo	Heat Analysis	..	…	B	0.06 max	B	0.10 max	B	B
	Product Analysis	..	…	B	0.07 max	B	0.11 max	B	B
Ti	Heat Analysis	..	…	B	B	B	0.05 max	B	B
	Product Analysis	..	…	B	B	B	0.06 max	B	B
(A) A, B, C, D, E, and F are classes of material used for Type 3 bolts. Selection of a class shall be at the option of the bolt manufacturer. (B) These elements are not specified or required.

ASTM A394 Mechanical Properties

ASTM A394 Hardness Requrments

Types	Min	Max
ASTM A394 Type 0-Rockwell B	80	100
ASTM A394 Types 1 and 3-Rockwell C	25	34

ASTM A394 Tensile Strength

Nominal Size, in.	Minimum Tensile Load, lbf
	Type 0B	Types 1 and 3C
1/2	10 500	17 050
5/8	16 700	27 100
3/4	24 700	40 100
7/8	34 200	55 450
1	44 850	72 700
(A) Based on 74 000 psi unit tensile strength. (B) Based on 120 000 psi unit tensile strength.

ASTM A394 Shear Strength

Nominal Size, in.	Minimum Load, lbf
	Type 0		Types 1 and 3
	Single Shear Strength Through Threads, lbfA	Single Shear Strength Through Body, lbfB	Single Shear Strength Through Threads, lbfC	Single Shear Strength Through Body, lbfD
1/2	6 950	9 000	9 350	14 600
5/8	11 150	14 100	15 050	22 850
3/4	16 650	20 250	22 450	32 850
7/8	23 150	27 600	31 150	44 750
1	30 400	36 050	41 000	58 450
(A) Based on 55 200 psi unit shear strength across the area at root of threads. (B) Based on 45 880 psi unit shear strength across the nominal area. (C) Based on 74 400 psi unit shear strength across the area at root of threads. (D) Based on 74 400 psi unit shear strength across the nominal area.

ASTM A394 Dimensions Length of Full Body for Bolts A

Length of Bolt, L, in.	Bolt Diameter, in.
	1/2	5/8	3/4	7/8	1
1	3/32	1/16	...	...	...
11/4	5/32	1/16	1/16	...	...
11/2	13/32	1/4	1/8	3/16	...
13/4	21/32	1/2	3/8	1/4	3/16
2 and longer in 1/4-in. increments	L minus 13/32	L minus 11/4	L minus 13/8	L minus 11/2	L minus 15/8
(A) Full body length is the distance from the underside of the head to the first scratch of thread for bolts with machine-cut threads or to top of the extrusion angle for bolts with rolled threads with a tolerance of ±1/32 in. for sizes 1/2 in. through 3/4 in., inclusive, and ±1/16 in. for size 7/8 in. and 1 in.

ASTM A394 Coating Tolerances

Nominal Bolt Diameter, in.	Oversize Limit, in.A
	Hot-Dip Zinc
1/2	0.018
5/8 , 3/4	0.020
7/8	0.022
1	0.024
(A) Hot-dip zinc-coated nuts are tapped oversize after coating.

ASTM A394 Bolting Surface Treatment Specifications

ASTM A394 Bolting Components Marking

Product Shall be Marked with our manufacturing trade mark "TorqBolt" or "TB" along with the designated Grade.
Grade and manufacturer’s identification symbols shall be applied to one end of studs and to the heads of bolts and screws of all sizes. (If the available area is inadequate, the grade symbol may be marked on one end and the manufacturer’s identification symbol marked on the other end.) For bolts and screws smaller than 1⁄4 in. [6 mm] in diameter and studs smaller than 3⁄8 in. [10 mm] in diameter and for 1⁄4 in. [6 mm] in diameter studs requiring more than a total of three symbols, the marking shall be a matter of agreement between the purchaser and the manufacturer.

Grade	Marking
ASTM A394 Type 0	TB 0
ASTM A394 Type 1	TB 1
ASTM A394 Type 3	TB 3