The article, published by G. Kurdjumow and G. Sachs from the Kaiser Wilhelm Institute for Metal Research in Berlin-Dahlem, discusses the mechanism of steel hardening, particularly the transformation of austenite (γ-iron) into martensite (α-iron). The authors describe how austenite, which contains carbon in a solid solution, transforms into a tetragonal phase during quenching, which is then converted into stable α-iron upon cooling, releasing carbon. They propose that this transformation involves a 24-fold stacking arrangement and simple shearing mechanisms. The article also explores the orientation of tetragonal and α-iron crystals to austenite, surface microstructures, and the role of mechanical processes in the transformation. The authors cite previous research and experiments to support their findings, including observations of dendritic voids and the parallel alignment of certain crystal planes.The article, published by G. Kurdjumow and G. Sachs from the Kaiser Wilhelm Institute for Metal Research in Berlin-Dahlem, discusses the mechanism of steel hardening, particularly the transformation of austenite (γ-iron) into martensite (α-iron). The authors describe how austenite, which contains carbon in a solid solution, transforms into a tetragonal phase during quenching, which is then converted into stable α-iron upon cooling, releasing carbon. They propose that this transformation involves a 24-fold stacking arrangement and simple shearing mechanisms. The article also explores the orientation of tetragonal and α-iron crystals to austenite, surface microstructures, and the role of mechanical processes in the transformation. The authors cite previous research and experiments to support their findings, including observations of dendritic voids and the parallel alignment of certain crystal planes.