PLASTIC DEFORMATION AND HEAT TREATMENT OF THIN WALLED CENTRIFUGALLY CAST HIGH STRENGTH CrMoNb STEEL TUBES

Abstract

This work deals with effects of hot plastic deformation process and subsequent heat treatment on structure and mechanical properties of centrifugally cast (CC) high strength CrMoNb steel tubes. Plate samples, taken from CC tubes, were homogenized and subsequently hot rolled. One serie of samples was soft-annealed (SA) and other series oil-quenched and tempered (QT) between 373-923 K. Primary and secondary structures, non-metallic inclusions in radial direction and prior austenite grain size were analyzed using bright-field and polarized light microsopy. Experimental mechanical properties of SA and QT samples were modeled by means of polynomial functions and correlated with structure properties.