resist the brittle effects of cold, sometimes to temperatures in the range of . Mangalloy is heat treatable, but the manganese lowers the temperature at which austenite transforms into ferrite. Unlike carbon steel, mangalloy softens rather than hardens when rapidly cooled, restoring the ductility from a work-hardened state. Most grades are ready for use after annealing and then quenching from a yellow heat, with no further need of tempering, and usually have a normal Brinell hardness of around 200 HB, (roughly the same as 304 stainless steel), but, due to its unique properties, the indentation hardness has very little effect on determining the scratch hardness (the abrasion and impact resistance of the metal). Another source says that the basic Brinell hardness of manganese steel according to the original Hadfield specification is 220 but that with impact wear the surface hardness will increase to over 550. Many of mangalloy's uses are often limited by its difficulty in machining; sometimes described as having "zero machinability." The metal cannot be softened by annealing and hardens rapidly under cutting and grinding tools, usually requiring special tooling to machine. The material can be drilled with extreme difficulty using diamond or carbide. Although it can be forged from a yellow heat, it may crumble if hammered when white-hot, and is much tougher than carbon steel when heated. It can be cut with an oxy-acetylene torch, but plasma or laser cutting is the preferred method. Despite its extreme hardness and tensile strength, the material may not always be rigid. It can be formed by cold rolling or cold bending. History Mangalloy was created by Robert Hadfield in 1882, becoming the first alloy steel to both become a commercial success and to exhibit behavior radically differing from carbon steel. Thus, it is generally considered to mark the birth of alloy steels. Benjamin Huntsman was one of the first to begin adding other metals to steel. His process of making crucible steel, invented in 1740, was the first time steel was able to be fully melted in a crucible. Huntsman had already been using various fluxes to help remove impurities from steel, and soon began adding a manganese-rich pig-iron called Spiegeleisen, which greatly reduced the presence of impurities in his steel. In 1816, a German researcher Carl J. B. Karsten noted that adding fairly large amounts of manganese to iron would increase its hardness without affecting its malleability and