METHOD OF FINING CRYSTAL GRAIN OF SILICON STEEL INGOT TO FINER GRAIN

摘要

PURPOSE:To fine the crystal grains of a silicon steel to the finer grains and to improve the toughness at ordinary temp. by rolling down a silicon steel ingot under respectively different temp. conditions by a difference in the content of S therein. CONSTITUTION:The silicon steel ingot is rolled down within the adequate range at the temp. within the adequate range in the figure indicating the relation between the draft and temp. without being cooled down to ordinary temp. after the casting if the silicon steel is the ' single phase steel of the alpha region where the content of the S is high in the binary constitutional diagram of Fe-Si in order to improve the toughness at ordinary temp. and to prevent cooling crack and the surface crack at the time of surface mending by fining the crystal grains of the silicon steel ingot to the finer grains. The ingot of the component compsn. corresponding to the (R)-alpha phase steel of the relatively low content of the S is again heated to the gamma region continuously after the ingot attains the alpha region by passing the gamma region or is rolled down at the temp. within the gamma region of the cooling stage of the ingot without being cooled down to ordinary temp. after the casting. The crystals of the silicon steel ingot are fined to the finer grains and the toughness at ordinary temp. is improved by the above-mentioned method.