FAQs For Infrastructure Construction Bolts

A325, Type 3, HDG And A490 Structural Bolts For Construction

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Top Questions And Answers For Structural Bolts

What type of nuts are used with structural bolts?

Heavy hex nuts are cast from carbon and alloy steel. Structural bolts need to be paired with the appropriate heavy hex nuts to form a dependable fastener assembly on structural elements. A563 nuts and A194 nuts have been made to match up with ASTM A325 and A490 structural bolts.

What is the difference between A325 and A490 structural bolts?

A325 and A490 structural bolts are made from medium carbon steel or weathering steel. A325 bolts are standard structural bolts made with minimum tensile strengths ranging from 105,000 PSI to 120,000 PSI. They can be galvanized. A490 bolts are used for heavier applications because they have a minimum tensile strength of 150,000 PSI. They cannot be galvanized.

What is an A490 structural Bolt?

A490 structural bolts are manufactured in compliance with ASTM criteria related to dimensional characteristics, mechanical features, tensile strength, and material type. They must have a minimum tensile strength rating of 150,000 PSI. These construction fasteners are made from either alloy or weathering steel, which makes them stronger than A325 bolts.

What is an A325 structural bolt?

An A325 structural bolt is made from heat-treated steel in accordance with ASTM material specifications that determine all mechanical features. ASTM standards also require a diameter range of 1/2 inch to 1-1/2 inches and tensile strength between 105,000 and 120,000 PSI. A325 threaded fasteners may be galvanized.

What grade is a structural bolt?

Various grades of structural bolts divide them into categories according to material, mechanical, and strength specifications. The strongest bolts have the highest grades. ASTM specifications are also used to categorize structural bolts by type and grade. ASTM A325 and A490 structural bolts are the most prevalent types.

What are structural bolts?

Steel-based structural elements are connected with hex bolts that can bear heavy loads. These structural bolts have hexagonal-shaped heads. Their short shanks are threaded below the neck. ASTM A325 and A490 specifications often guide the manufacturing of heavy hex bolts. These standards apply to many attributes, such as diameter range, tensile strength, and material.

What are structural bolts used for?

Steel-to-steel structural components that bear heavy loads need the strength of structural bolts. These fasteners have superior strength compared to standard hex bolts. They are meant to hold vital structural joints that need very strong bolts. The enhanced holding power of structural bolts makes them useful in a variety of construction applications.

What are structural bolts made from?

Structural bolts are commonly made from medium carbon steel, medium carbon alloy steel, and weathering steel. Material types determine their grade and ASTM specifications. Standard structural bolts may undergo hot-dipped galvanization. ASTM A325 bolts with type 1 specifications may also be dipped, but A490 structural bolts will not have this exterior treatment.

How long should structural bolts be?

Structural bolts tend to be shorter and thicker than other bolts. They come in lengths from 1 inch up to 3-1/4 inches. Length equals the measurement from the base of the head to the end of the threads. These fasteners usually have a length four times greater than their diameter. To install structural bolts, select a length that extends beyond a connection site so that a nut can be installed.

How are structural bolts installed?

Steel parts fastened with structural bolts are secured with nuts. Hoisting applications need at least two structural bolts for each connection. The remaining bolts are tightened after the structure has been plumbed to create even connections. Heavy hex head structural bolts require tightening close to their proof strength to deliver appropriate tension.