ASTM A490M Structural Heavy Hex Bolts
ASTM A490M - 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 Type 2 was withdrawn in 2002.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 A490M Grades
ASTM A490M Properties
ASTM A490M 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 A490M Mechanical Requirement |
| Nominal Diameter, mm |
Tensile Strength, min, Mpa |
Yield Strength, min, Mpa |
Elongation in 4D, min, % |
Reduction in Area, min, % |
| M12 to M36, Inclusive |
1040 - 1210 |
940 |
14 |
40 |
Hardness Requirements for ASTM A490M Bolts
| Bolt Size, mm |
Bolt Length*, mm |
Brinell |
Rockwell C |
| min |
max |
min |
max |
| M12 to M24, inclusive |
Less than 2D |
311 |
352 |
33 |
39 |
| M12 to M24, inclusive |
2D and over |
-- |
352 |
-- |
39 |
| M25 to M36, Inclusive |
Less than 3D |
311 |
352 |
33 |
39 |
| M25 to M36, Inclusive |
3D and over |
-- |
352 |
-- |
39 |
Note* : Heavy Hex Structural Bolts M24 and smaller and shorter than 2D are subject only to minimum and maximum hardness. Heavy hex structural bolts larger than M24 through M36 inclusive in diameter and shorter than 3D are subject only to minimum and maximum hardness.
ASTM A490M 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 A90M Bolt Marking
| Grade |
Marking |
| A490M Type 1 |
A490M |
| A490M Type 3 |
A490M |