焼ならしを繰返した片状黒鉛鋳鉄の諸性質

抄録

  From the growth test, it was suggested that cyclic normalization modified cast iron. Therefore in this paper, to make sure of the result the iron of the class of FC 250 was normalized repeatedly between 1223 K and room temperature up to 15 cycles and some properties were investigated in details. The main results obtained were as follows. With cyclic normalization, irreversible expansion increased and density decreased, but by only one normalization, it was found that tensile strength increased by about 20 %, damping capacity increased by about 10 % and moreover thermal conductivity was almost equal to that of as cast. Therefore the heat treatment by only one normalization was considered to raise the additional value of cast iron easily. This fact might prove to be a new and effective knowledge to manufacture brake materials with low squeak noise for cars, damping materials and so on.