Scope
HEXAGON HEAD BOLTS
ASTM A490
Structural Bolts
The ASTM A490 specification covers quenched and tempered, alloy steel, heavy hex structural bolts from ½” diameter through 1½” diameter with a minimum 150 ksi tensile. These bolts are intended for use in structural connections and therefore have shorter thread lengths than standard hex bolts. Refer to the Structural Bolts page of our site for thread lengths and other related dimensions. A490 bolts are similar in application and dimensions to A325 heavy hex structural bolts but are made from an alloy steel rather than a medium carbon steel, resulting in a higher strength fastener.
The A490 specification is applicable to heavy hex structural bolts only. For bolts with different thread lengths than specified for structural bolts but with similar mechanical properties, see Specification A354 grade BD.
ASTM A490 bolts shall not be coated by hot-dip galvanizing, mechanical deposition, or electroplating with zinc or other metallic coatings due to the potential risk of hydrogen embrittlement.
Additional testing in the form of Magnetic Particle Inspection for Longitudinal Discontinuities and Transverse Cracks is a requirement of the A490 specification.
Types
Connection Types
Mechanical Properties
SizeTensile, ksiYield, ksiElong. %, minRA %, min
| 1/2 - 1-1/2 | 150-173 | 130 | 14 | 40 |
Recommended Nuts and Washers
NutsWashers
Type 1Type 3Type 1Type 3
| A563DH | A563DH3 | F436-1 | F436-3 |
Note: Nuts conforming to A194 Grade 2H are a suitable substitute for use with A490 heavy hex structural bolts. Follow the link for an ASTM A563 Nut Compatibility Chart.
Notes
- The bolts shall not be coated by hot-dip zinc coating, mechanical deposition, or electroplating with zinc or other metallic coatings due to the potential for hydrogen embrittlement. Read more aboutissues with galvanizing ASTM A490.
- Each sample representative of the lot shall be magnetic particle inspected for longitudinal discontinuities and transverse cracks.
