What is the difference between AR400 steel and AR450 steel?

Abrasion resistant (AR) steel plate is a high-carbon alloy steel plate.  AR material is produced by quenching and tempering forged steel blocks, or ingots. During this process, the grain structure is changed to increase toughness and encourage formability (or, to be less brittle), and results in through-hardening of the material.

Before we dive into the difference between AR400 steel and AR450 Abrasion resistant steel, it is important to clarify that AR steels are not governed by an ASTM code or a specific chemistry, but a level of hardness.

Different mills may have different “recipes” for AR steel, but produced material is administered a hardness test – known as the Brinell Test – to determine the category in which it falls.

The technical difference between AR400, AR450 and AR500 is the Brinell Hardness Number (BHN), which indicates the material’s level of hardness. Materials with higher BHNs have greater levels of hardness, while materials with lower BHNs have lower levels of hardness:

AR400: 360-440 BHN Typically

AR450: 430-480 BHN Typically

AR500: 460-544 BHN Typically

Application

Applications requiring AR400 AR450 material that can resist extreme levels of wear and stress – such as mining equipment and concrete handling – typically use plate grades with higher BHNs. Project engineers for these applications may choose AR500 or AR600 plate, as they are some of the hardest AR grades and, therefore, well-suited for wear resistance.

Some applications require more moderate levels of wear resistance, such as construction equipment. In these circumstances, project engineers may opt for AR plate grades with a lower BHN, such as AR400 and AR450. These grades are durable enough to handle high wear and stress without sacrificing other desirable material qualities, such as ductility.