F3125 Grades

A325

Under the A325 grade, there are multiple different types. By far, the most common type of A325 bolt is the A325 type 1, you’ll also see this written as A325-1 or just A325.

• Type 1 – This is your typical standard structural bolt. The A325 bolt is made from medium carbon steel that has been heat treated to be at least 120ksi in tensile strength. The standard thread length for these bolts are 2x the diameter + ¼” if it’s shorter than 6” or 2x the diameter + ½” if the bolt is longer than 6”. If you don’t specify, you will be provided with the standard thread length.
• Type 2 – This grade no longer exists. It was withdrawn in November 1991.
• Type 3 – The A325-3 bolts are made from weathering steel. It had the same strength requirements as A325-1, however, the steel for A325-3 bolts includes copper, chromium, and nickel. Weathering steel is made because it forms an oxide coating to protect the steel from corrosion.
• A325T – This is exactly the same thing as A325-1 bolts except they are fully threaded. The A325T bolts are only available up to 4x the diameter in length.

Along with these types of A325, there are also connection types. This doesn’t affect how the bolts are made at all, they simply specify the application of the bolts after they are made. The connection types are as follows.

• SC – Slip critical connection.
• N – Bearing type connection when the threads are included in the shear plane.
• X – Bearing type connection when the threads aren’t included in the shear plane.

A325M

This covers the metric size of A325 which are made from M12 to M36. The only difference between these bolts and regular A325’s is they are measured in metric vs imperial.

A490

The ASTM A490 is the high-strength version of the A325 grade. The A490 tensile strength ranges from 150- 173ksi for tensile strength depending on the diameter of the bolt. Besides a difference in strength, all of the requirements are the same as A325 bolts. Since A490 bolts are of such a high strength they cannot be galvanized because they run the risk of hydrogen embrittlement which could make them structurally unsound. The ASTM A490 specification allows for the configurations to be heavy hex structural bolts or threaded rod. However, the specification does not allow for fully threaded head bolts.

• Type 1 – This is the typical standard high-strength structural bolt. This can also be written as A490-1, A490 type 1, or just A490.
• Type 3 – The A490-3 bolts are the same strength as A490 bolts but they are made from weathering steel. Weathering steel is known for its protective properties from corrosion. This type of bolt can be written as A490-3 or A490 type 3.

A490M

This covers the metric size of A490 which is made from M12 to M36. The only difference between these bolts and regular A490’s is they are measured in metric vs imperial.

F1852

Also known as A325 TC bolts or A325 tension control bolts. This specification covers two types of heat-treated, steel, tension control bolt-nut washer assemblies. A tension control bolt assembly is made up of the bolt with a spline end and a corresponding nut and washer. These bolts are exclusively sold as assemblies. The purpose of tension control bolts is to create the minimum tension required. The minimum tension is based on which grade of TC bolt you use. You find this tension by applying torque to the nut while simultaneously applying a counter torque to the spline using a specific spline drive installation tool.

These assemblies are capable of developing a minimum predetermined tension when installed by applying torque to the nut, while at the same time applying a counter torque to separate the spline end from the body of the bolt using an appropriate spline drive installation tool. The fastener assemblies are intended for use in structural connections. F1852 bolts may only come in plain or mechanically galvanized coatings.

F2280

Also known as A490 TC bolts, this specification covers two types of heat-treated, steel, tension control bolt-nut-washer assemblies, also referred to as “sets,” having a tensile strength of 150 to 173 ksi. These bolts are exclusively sold as assemblies. The purpose of tension control bolts is to create the minimum tension required. The minimum tension is based on which grade of TC bolt you use. You find this tension by applying torque to the nut while simultaneously applying a counter torque to the spline using a specific spline drive installation tool.

These sets are meant to be used in structural connections. The assemblies are available with either round (button or dome) heads, or heavy hex structural heads. F1852 bolts may only come in plain or mechanically galvanized coatings.