Development of Damping Material Composed of Rolled Graphite Cast Iron and Mild Steel
Shizuo Mukae, Kazumasa Nishio, Mitsuaki Katoh, Taiji Torigoe, Mitsuru Yano
Composite specimens with 3- and 5-layers composed of a mild steel and spheroidal graphite cast irons (steel/cast iron/steel, steel/cast iron/steel/cast iron/steel) were fabricated using diffusion bonding. The composite specimens were hot rolled and the final reduction was 88% and 92%. The main results obtained are as follows; (1) When the hot rollings of 92%-reduction were carried out for the composite specimens, cracks were not observed in the cast iron and on the bond interface between the mild steel and the cast iron. By the hot rolling, spheroidal graphites in the cast iron became the form of sheet. (2) The tensile strength of the rolled composite sheets with pearlitic structure was higher than that of the mild steel. In case of ferritic structure the strength of the sheet with 3-layers was a little lower than that of the mild steel, however, the strength of the sheet with 5-layers was higher than that of the mild steel. (3) The specific damping capacity of the rolled composite sheets was higher than that of the mild steel and increased with increasing the reduction and the number of the layer. (4) The damping effect of the sound pressure of the gear made of the rolled composite sheet with 9-layers was very high in comparison with that of the gear made of the mild steel.