鋳鉄のオーステナイト域温度における力学的性質

抄録

  Tensile deformation at high temperatures of cast iron with flake graphite (FC 20 and 30, and non-magnetically austenitic Ni-Mn-Cu system) and spheroidal graphite (FCD 40 and 70) was examined in the temperature range of 900∼1,120°C and strain rate range of 1.0×10⁴∼1.25×10²/sec. Tensile strength, yield strength, elongation and reduction of area depend very much on test temperature and strain rate. The tensile strength of FCD 40 is almost equal to that of FCD 70 within experimental conditions. FC 20 and 30 also exhibit almost equal tensile strength within the experimental range. Tensile strength of each cast iron can be accurately predicted by quadratic form of (1,000/T) and log ε, where T is the temperature (K) and ε is the strain rate (1/sec). Flow stress of spheroidal graphite cast iron can also be determined by quadratic form of (1,000/T), log ε and (100ε) where ε is the true strain. Ductility of spheroidal graphite cast iron is remarkedly reduced when the strain rate exceeds 10/s.