Development of a new, high toughness, abrasion resistant plate steel

Full scale production, laboratory testing, and field testing of a new, patented, abrasion resistant plate steel ale described. Research on quenched and lightly temper ed Mn-Cr steels lead to the development of a patented alloy with a two-phase microstructure consisting of lath martensite and thin. continuous films of stable retained austenite. Compared to conventional steels with a similar hardness of 500 HBN, this new alloy (trademarked MAXIMA(TM)) exhibits superior toughness. Bottom-poured slab ingots of the alloy were produced via electric furnace melting, ladle refining, and vacuum degassing. The slab ingots were hot rolled to 19 mm (0.75 in.) and 25 mm (1.0 in.) thick plates on two different U.S. plate mills. The plates were then roller-quenched and tempered to produce the desired properties. The following results were achieved in 19 tnm (0.75 in.) thick plates: Hardness = 477/500 HBN, Yield Strength = 1190 MPa (172 ksi), Tensile Strength = 1460 MPa (212 ksi), longitudinal CVN at -40 degreesC (-40 degreesF) = 43 J (32 ft-lb). Laboratory weld tests, bend tests, abrasion tests, and field observations in applications such as mining dump truck bed liners have shown the new steel to have good weldability, formability, and abrasion resistance. The high impact resistance of the 2-phase microstructure can provide extended life in abrasion applications involving impact loading.