HISTORY ATLAS TOOL STEELS - HOT WORKING ROLLING PROPERTIES AND
MICROSTRUCTURES
H.J. McQueen
1
Prof. Emeritus, Mech. Ind. Eng., Concordia University, Montreal, Canada H3G 1M8
hugh.mcqueen@concordia.ca
ABSTRACT
From a crucible steel facility purchased in 1920, Atlas (Specialty) Steels arose in 1928 and by
1932 utilized an electric arc furnaces to transform purchased steel into tool and specialty grades. The
furnaces expanded to six in WW2 with production in thousands of tons, thus becoming a world scale
suppliers. In 1949-52, it expanded into stainless steels with sheet and bar rolling capacity. Although the
alloy carbide precipitates in tool steels had been determined, the microstructures, flow stresses and
ductilities developed during hot rolling were only clarified in the period 1984-2004 by hot torsion tests at
constant temperature T and rate. The flow curves exhibited a peak and flow-softening characteristic of
dynamic recrystallization that was delayed to higher strains by increased carbides. Briefly as T rose, the
strength decreased and the ductility increased as the alloy carbides dissolved; however, burning limited
ductility. At selected strains up to the ductility limit, microscopy indicated that dislocation substructures
developed in relation to morphology and distribution of the carbides. The behaviors of M2, D2, A2, H13
and W1 were determined and enabled explanation of the T ranges and strengthening effects of various
carbides.