of metal fibers the formulations selected in relation to the measured mechanical properties have been tested in the construction of spouts for pouring ladles where they have been shown to perform better with regard to the lifetime of the components tested the experiments have also shown that during the preparation of the castable refractory the dispersion of the ceramic fibers in the mixture constituting the castable refractory was much easier than the dispersion of the metal fibers the fibers according to the invention can be manufactured by the technique commonly used to produce sintered bauxite for abrasives as described in the patent u s pat no 3 239 970 for carborundum that is to say by the crushing of natural bauxite calcination mixing in a binder to form a paste extrusion of the paste cutting of the fibers and sintering at a temperature of the order of 1400 u00b0 c the patent states that the section of the extruded products may be round square triangular or polygonal a section which is particularly well suited for the implementation of the invention is a section that includes concave surfaces for example in the form of a star which improves the anchoring of the fiber in the refractory material the diameter or equivalent diameter of the fibers is preferably between 0 2 and 1 mm in the case of the reinforcement of a castable refractory based on metal oxides particularly alumina and silica the constituents of the castable refractory are dry mixed in a mixer the fibers are then incorporated into the mixture and then the water and the whole is stoved at a temperature of the order of 1500.