= Solution
As-quenched <martensite> generally has greater <hardness> and strength, but lower ductility and <toughness>, than ordinary pearlitic steel. Its supersaturated <carbon> and distorted lattice impede <dislocation glide>; quench <stresses> also promote cracking. <Pearlite> combines hard <cementite> lamellae with more deformable <ferrite>, with finer spacings generally giving greater strength. \b[Austenitize, quench to <martensite>, then temper] to obtain a useful compromise between indentation resistance and resistance to fast fracture. Tempering below the austenitizing range relieves <stresses> and develops a fine carbide-containing microstructure. It trades some maximum <hardness> for improved <toughness>; the <temperature> and time must suit the required balance.
Back to article page
