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ASTM A325 Specification

ASTM A325 - Standard Specification for Structural Bolts, Steel, Heat Treated 830 MPa Minimum Tensile Strength

This specification covers two types of quenched and tempered steel heavy hex bolts in metric and imperial sizes for structural purpose. Metric size bolts are produced from M12 to M36 as per ASTM A325M & imperial size bolts are produced from 1/2" to 1-1/2" as per ASTM A325. These boltings are intended for used in structural connections. FerroBend manufactures and supplies ASTM A325 Type 1 & Type 3 heavy hex bolts with EN 10204 Type 3.1 Certification.

ASTM A325 Bolt Grades

Grade Class
Type 1 Carbon Steel, Carbon Boron Steel, Alloy Steel or Alloy Boron Steel
Type 2 Withdrawn
Type 3 A B C D E F

ASTM A325 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 -- --

ASTM A325 Mechanical Properties

Nominal Diameter, Inch Tensile Strength, min, ksi Yield Strength, min, ksi Elongation in 4D, min, % Reduction in Area, min, %
1/2" to 1", Inclusive 120 92 14 35
Over 1 to 1-1/2" 105 81 14 35

ASTM A325 Hardness Requirements

Bolt Size, Inch Bolt Length, Inch Brinell Rockwell C
Min Max Min Max
1/2" to 1", inclusive Less than 2D
2D and over
253
--
319
319
25
--
34
34
1-1/8" to 1-1/2", inclusive Less than 3D
3D and over
223
--
286
286
19
--
30
30

where D is nominal diameter or thread size

ASTM A325 Bolt Marking

Grade Marking Details
Type 1 Type 1 bolts shall me marked "A325M" and "8S". In addition, bolts marked "8.8S" shall be an acceptable marking
provided they also meet the requirements of ISO 7412.
Type 3 Type 3 bolts shall me marked "A325M" and "8S3". In addition, bolts marked "8.8S3" shall be an acceptable marking
provided they also meet the requirements of ISO 7412. The use of additional distinguishing marks to indicate
the bolts are weathering steel shall be the manufacturer's discretion.

ASTM A325 Recommended Nuts & Washers

Finish Bolt Grade Nut Grade Washer Grade
Plain (Non Coated) Type 1 & Type 3 ASTM A563 Grade 8S or 8S3 ASTM F436
Zinc Coated Type 1 & Type 3 ASTM A563 Grade 10S ASTM F436
Coated in accordance with ASTM F1136M Type 3 ASTM A563 Grade 10S ASTM F436
Plain Type 1 & Type 3 ASTM A563 Grade 8S3 ASTM F436