Abstract: The present invention is concerned with a method of making material for shadow masks to be incorporated in cathode ray tubes for colour TV sets.A coil of cold rolled low carbon Al-killed steel is forcibly decarburized through an open coil annealing until a quench aging index QAI becomes 3.0Kg/mm.sup.2. This QAI is specified as follows: ##EQU1## wherein, W1: load (Kg) giving 10% tensile strain to the said decarburized material having been soaked at temperature of 500.degree. C. for 10 minutes and subjected to a water coolingS: cross sectional area (mm.sup.2) of a test piece when giving said 10% tensile strainW2: yield point load (Kg) provided by the strain effected material aged at temperature of 100.degree. C. for 4 hours.After the forcible decarburization, the steel is subjected to an ordinary re-cold rolling, photo-etching, final annealing and pressing.