鋳物砂添加剤としての球状化ピッチの炭化過程について

抄録

  When the amorphous carbonaceous materials are used as mold additives, the degree of castig finish and the facilitation of shake out are considered to be influenced by carbonization-process and the carbonized degree of the used materials.
  So the author has studied on the carbonization process of amorphous carbon, such as spheroidized blown coal pitch in the molding sand, using X-ray diffractmeter, differential thermal analysis, thermo balance and Polarization microscope.
  The results obtained were as follows :
1) The wetting phenomenon between spheroidized blown coal pitch and sand grains were a immersional wetting.
2) The carbonization process of spheroidized blown coal pitch and coal pitches with X-ray diffraction analysis were indicated diffuse patterns of (002) line, and (100) line appeared in the process of crystallite growth with increasing temperature.
For some carbonized pitches, the distribution of size of layers and of packing number of layers were obtained from (100) and (002) line profiles respectively.
As the process was advanced, the crystallite growth was indicated by the shape of the curves which assumed a more pronounced and definite peak.
3) The crystal structure of spheroidized blown coal pitch (P) is more carbonized at low temperature that of non-blown coal pitch (p').
4) The pyrolysis of spheroidized blown coal pitch occurs between 250°C to 450°C strongly. Higher is the softening point of the pitch such as spheroidized blown coal pitch, higher is the residual coke content of it.
5) On pouring the molten metal, spheroidized blown coal pitch coated on the sand grain with the paste state change into a residual coke in proportion to the degree of heat treatment. Therefore, it is effective to get fine surface of the casting.