What Is AR Steel Anyway?

Abrasion resistant steel (AR), also known as wear plate, and sometimes just hardened steel, is a special type of steel designed for heavy friction environments. It is utilized by many industries where the lifespan of parts would be drastically shortened if not for its special design.

Below are some items that rely upon abrasion resistant steel, and how they benefit from it:

  • Packer blades in garbage trucks – protects against constant scraping and grinding
  • Large disposal containers – resistance to denting and gouging
  • Shredders – high toughness decreases cracking and wear
  • Excavator buckets – maintaining strength on blade edge and/or side integrity
  • Bulldozer – protects the bucket blade from chipping, denting and thinning
  • Dump trucks – allows for lighter construction weight with added strength and wear resistance
  • Rail road cars – durability and strength to withstand constant use

With just a few examples, it is clear to see just how useful abrasion resistant steel is to many industries. But how does it work exactly, and what is it that allows steel to become hardened?

Steel is an alloy of iron and carbon, where carbon acts as a hardening agent (there are also a host of other materials that can be added to the iron/carbon mixture which help to produce steel with certain desired properties). Carbon content, though, is what we often refer to when talking about the hardness of steel. In its simplest form, hardening steel can be achieved by quenching. Quenching involves heating steel to the austenite phase (the temperature at which the steel changes crystal structure from ferrite to austenite – ferrite being the most stable form of pure iron at room temperature which can dissolve only a small amount of carbon, and austenite being the same the same iron, only at 910 °C where it can dissolve 38 times the amount of carbon) and then submerging it in either cold water or oil. The rapid cooling yields a hard, but very brittle material. This is not ideal as it is very susceptible to fractures and breaking. To fix this problem the steel is tempered – a special type of annealing – which simply put is just heating the steel to an adequate temperature to soften it, and allowing it to cool gradually. The point is not to undo the hardening process, but to facilitate recovery, recrystallization and grain growth, which yield a more ductile, fracture-resistant steel.

Steel production has come a long way since its beginning roughly 4,000 years ago. Different companies have put an incredible amount of time, energy and expertise into developing hardened steels; some use only surface hardening which leaves the centre of the steel not as hard as the outside, where others like Hardox brand have developed methods to harden their steel the entire way through, producing superior results that can even withstand rifle rounds. The applications for AR steel are widespread, and with continued research and development the ways in which we use it will only increase. This is a great thing, because materials that work harder and last longer are what allow us to get jobs done.