ASTM (American Society for Testing and Materials) has several standards for bolts used in steel construction. Some common types include:
- ASTM A325: High-strength structural bolts, with a heavy hex head and washer face, used in structural steel connections. They are used in a wide range of applications, such as in steel-to-steel connections, and are available in three types: Type 1 (medium carbon, carbon boron, alloy steel), Type 3 (weathering steel) and Type 4 (stainless steel).
- ASTM A490: High-strength structural bolts, with a larger diameter and longer thread than A325, also used in structural steel connections. They are used in heavy load-bearing connections, such as in bridges and high-rise buildings.
- ASTM F3125: A newer standard that includes several grades, such as A325, A490, and F1852 (twist-off-type tension control structural bolt assemblies). This standard provides a unified approach to structural bolt selection and allows for greater flexibility in design and construction.
Additionally, ASTM A307 carbon steel bolts and studs can also be used in steel detailing, especially in non-critical connections.