ASTM A325 Specification

ASTM A325 Specification for heat treated carbon & weathering steel bolts, steel with 120 ksi Minimum Tensile Strength, for use in structural bolting applications.

ASTM A325 specification covers two types of quenched and tempered steel heavy hex bolts in metric and imperial sizes for structural purpose. The specification includes type 1 & type 3 fastener material intended for structural bolting purpose. Type 1 is a heat treated high strength plain carbon, carbon-boron, alloy steel or alloy boron steel bolting materials with minimum tensile requirement of 105 ksi, yield 81 ksi and maximum hardness limit of 25 - 35 HRC. Type 3 is heat treated weathering steel bolting material with similar strength requirement to type 1 but greater corrosion protection and are prominently used in humid weather conditions.

Bolt Grades

Grade Class / Description
Type 1 Carbon Steel, Carbon Boron Steel, Alloy Steel or Alloy Boron Steel
Type 2 Withdrawn

Type 3		 Weathering Steel
A B C D E F

Chemical Composition

Element Type 1, % Type 3, %
Carbon Steel Carbon Boron Steel Alloy Steel Alloy Boron Steel A B C D E F
Carbon 0.28 - 0.55 0.28 - 0.55 0.28 - 0.55 0.28 - 0.55 0.31 - 0.42 0.36 - 0.50 0.14 - 0.26 0.14 - 0.26 0.18 - 0.27 0.19 - 0.26
Manganese 0.57 min 0.57 min 0.57 min 0.57 min 0.86 - 1.24 0.67 - 0.93 0.76 - 1.39 0.36 - 1.24 0.56 - 1.04 0.86 - 1.24
Phosphorus 0.048 max 0.048 max 0.040 max 0.040 max 0.040 max 0.040 max 0.040 max 0.040 max 0.040 max 0.040 max
Sulfur 0.058 max 0.058 max 0.045 max 0.045 max 0.045 max 0.045 max 0.045 max 0.045 max 0.045 max 0.045 max
Silicon 0.13 - 0.32 0.08 - 0.32 0.13 - 0.37 0.13 - 0.37 0.13 - 0.37 0.25 - 0.55 0.13 - 0.37 0.20 - 0.55 0.13 - 0.37 0.13 - 0.37
Boron ... 0.0005 - 0.003 ... 0.0005 - 0.003 ... ... ... ... ... ...
Copper ... ... ... ... 0.22 - 0.48 0.17 - 0.43 0.17 - 0.53 0.27 - 0.53 0.27 - 0.63 0.17 - 0.43
Nickel ... ... ... ... 0.22 - 0.48 0.47 - 0.83 0.22 - 0.53 0.47 - 0.83 0.27 - 0.63 0.17 - 0.43
Chromium ... ... ... ... 0.42 - 0.68 0.47 - 0.83 0.27 - 0.53 0.45 - 1.05 0.55 - 0.95 0.42 - 0.68
Vanadium ... ... ... ... ... ... 0.010 min ... ... ...
Molybdenum ... ... ... ... ... 0.07 max ... 0.11 max ... ...
Titanium ... ... ... ... ... ... ... 0.06 max ... ...

Mechanical Properties

Nominal
Diameter,
Inch		 Tensile
Strength, min,
ksi		 Yield
Strength, min,
ksi		 Elongation
in 4D, min,
%		 Reduction
in Area, min,
%		 Bolt Length,
Inch		 Brinell Rockwell C
Min Max Min Max
1/2" to 1", Inclusive 120 92 14 35 Less than 2D
2D and over		 253
...		 319
319		 25
...		 34
34
Over 1 to 1-1/2" 105 81 14 35 Less than 3D
3D and over		 223
...		 286
286		 19
...		 30
30

where D is nominal diameter or thread size.

Recommended Nuts & Washers

Nuts Washers
Type 1 Type 3
Type 1
Type 3
Plain Galvanized Plain
ASTM A563 Grade C, C3, D, DH, DH3 ASTM A563 Grade DH ASTM A563 Grade C3, DH3 ASTM F436 Type 1 ASTM F436 Type 3