A bimetallic composite working cylinder has an external shell made of an alloy containing iron, carbon, vanadium, chromium and molybdenum. The range of composition of the alloy represented on a carbon-vanadium curve is delimited by a quadrilateral whose sides are: a) the constant ordinate line V=3 wt.%; b) the constant abscissa line C=3wt.%; c) the peritectic line separating the delta et gamma phase regions; and d) a straight line which determines the maximum permissible vanadium content passing through two points with co-ordinates C=1.8 %, V=6% and C=3%, V=4.5%, respectively. The core of the cylinder is made of nodular graphite iron.