Recently, I worked on a quote that involved rolling cones that were made out of AR400 steel plate. AR400 was something that I was not very familiar with so I took some time to research it and see how it would react during the bending/rolling process. AR400 and AR360 are wear-resistant grades of abrasion resistant steel plate. The “AR” in the material name comes from the “abrasion resistant” terminology. This material is commonly used in situations where the material is constantly being impacted by outside forces. Some functional examples that are typical of the need for abrasion resistant steel would be the bed of a dump truck, the scooping bucket of a backhoe, or an agriculture funnel.
Because AR400 and AR360 are so hard, extra care for the material must be taken during the rolling process. The tensile strength and thickness of material can cause materials to have a lot of springback. Springback is a term in bending and curving of steel which refers to the way the material will attempt opening back up towards its original position after being formed. We think of steel as something stiff and rigid, but there are still elastic properties at work which cause the material to relax a little after bending. When a rolling and bending company deals with material like this they must over bend the material to get the desired radius. The unique properties of AR400 and AR360 cause the material to have a lot of springback. For these abrasion resistant materials, they must be bend to a tighter initial radius than standard mild steel to end up with the same finished radius.
In order to accurately manufacture pieces like this it take a combination of effort from operator and estimator. The estimator must be aware that certain material will open up 5 deg. or more and alert the operator that some trial and error might be necessary to get to the desired radius.