The Need for Hardness
AND Toughness

  Toughness is not often discussed by distributors of standard grades of AR plate, such as AR400 or AR500 and their various trade names. Hardness is their primary focus for wear resistance. Hardness is defined as the resistance to penetration, and is necessary where hard or sharp materials are in motion against a solid surface.
  However, the “harder the better” is not always true. Wear research has demonstrated that the main way solid surfaces wear out cannot be prevented merely by hardness. Most wear is caused by fracture, defined as the abrupt removal of material by breaking, chipping, or cutting. Examples of fracture wear include  knife edges, blades and concrete surfaces. These items are worn not by a gradual removal of the surface or by penetration by hard, sharp objects, but by a chipping and breaking away of the surface particles by fracture. The property that resists fracture is toughness, largely sacrificed in the making of AR plate, but engineered from the start in Mangabraze.
  With hard facing and overlays, other engineers have tried to achieve what has always been there in Mangabraze. But why deal with the numerous problems encountered with overlay?
  This custom made plate, exclusive to Baldwin, is specially milled for toughness as well as hardness. The 2% level of Manganese (compared to 1% in generic AR plate) allows for the formation of carbides, highly compact binary compounds of carbon and heavy metals, that promote high degrees of wear resistance such as those used in metal-cutting carbide tool bits.
  The 1 1/2% level of Nickel (compared to trace - 0.1% in generic AR plate) promotes deeper, more uniform hardening by essentially acting as structural supports within the steel.