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ASTM A490 Structural Heavy Hex Bolts

ASTM A490 - Standard Specification for Structural Heavy Hex Bolts, Alloy Steel, Heat Treated, 150 ksi Minimum Tensile Strength with Type 1 & Type 3 Weathering Steel Bolting Class

This specification covers two types of bolting grades quenched and tempered, manufactured from high strength alloy steel. ASTM A490 Bolts are intended for used in structural connections similar to ASTM A325/A325M but being produced from alloy steel instead of medium carbon steel, possed high tensile strength. There are two versions of this specification; ASTM A490 covering imperial sized high tensile bolting and A490M for metric sized bolts. ASTM A490 covers two grades Type 1 & Type 3, the later being weathering steel. Type 2 was withdrawn in 2002. Bolts under this specification are manufactured from 1/2" to 1-1/2" in imperial & from M12 to M36 in metric sizes. Ferrobend is a outstandig performer in providing ASTM A490 Type 1 & Type 3 weathering steel bolts with zinc, cadmium or dacromet coatings with EN 10204 Type 3.1 Certification.

ASTM A490 Grades

Grade Class
Type 1 Medium Carbon Alloy Steel
Type 2 Withdrawn
Type 3 Weathering Steel

ASTM A490 Properties

ASTM A490 Chemical Composition

Element Type 1 % Type 3 %
Carbon 0.20 - 0.53 (3/4" and smaller) 0.30 - 0.48 (sizes through 1-3/8")
0.30 - 0.53 (larger than 3/4") 0.35 - 0.53 (for 1-1/2")
Manganese, min 0.400 --
Phosphorus, max 0.035 0.040
Sulfur, max 0.040 0.040
Copper 0.20 - 0.60 --
Chromium, min 0.45 --
Nickel, min 0.20 --
Molybdenum, min 0.15 --

ASTM A490 Mechanical Requirement

Nominal Diameter, inch Tensile Strength, min, ksi Yield Strength, min, ksi Elongation in 4D, min, % Reduction in Area, min, %
1/2" to 1-1/2", Inclusive 150 - 173 130 14 40

Hardness Requirements for ASTM A490 Bolts

Bolt Size, mm Bolt Length*, mm Brinell Rockwell C
min max min max
1/2" to 1", inclusive Less than 2D* 311 352 33 39
1/2" to 1", inclusive 2D and over -- 352 -- 39
1-1/8" to 1-1/2", inclusive Less than 3D 311 352 33 39
1-1/8" to 1-1/2", inclusive 3D and over -- 352 -- 39

Note* : Heavy Hex Structural Bolts 1" and smaller and shorter than 2D are subject only to minimum and maximum hardness. Heavy hex structural bolts larger than 1" through 1-1/2" inclusive in diameter and shorter than 3D are subject only to minimum and maximum hardness.

ASTM A490 Heat Treatment

Type 1 and Type 3 bolts shall be heat treated by quenching in oil from the austenitic temperature and then tempered by reheating to a temperature of not less then 800°F.

Recommended Nuts & Washers

Bolt Type and Finish Nut Class and Finish Specification Washer Finish
Plain (noncoated) ASTM A563-DH, DH3, plain (uncoated) Plain (uncoated)
Coated in accordance to ASTM F1136, Grade 3 ASTM A563, coated in accordance to ASTM F1136, Grade 5 Coated in accordance to ASTM F1136, Grade 3
Weathering steel ASTM A563-DH3, weathering steel Weathering steel

ASTM A490 Bolt Marking

Grade Marking
A490 Type 1 A490 / A490M
A490 Type 3 A490