黒心可鍛鋳鉄の諸性質に及ぼす銅の影響に就いて

抄録

  Recently it became difficult to buy the blast furnace pig iron and moreover the quality is very bad. Therefor as a substitute for it, we are compelled to make the black heart malleable cast iron from the electric furnace pig iron.
  But the electric furnace pig iron that we buy recently is made from the pyrite cinder and therefor, it contends much of copper necessarily. Accordingly we investigated the effect of copper on various properties of the black heart malleable cast iron.
  The result of the experiment was summarised as follows :
  ① As the copper content in the black heart malleable cast iron increases the first stage and the second stage gratiphization time nearly decrease exponentially.
  ② As the copper content in the black heart malleable cast iron increases the grain size and the temper carbon after the complete annealing become somewhat small.
  ③ We can considerably prevent the embrittlement with the copper addition to the black heart malleable cast iron. But if the embrittlement is slight, we completely prevent it by the 0.8% copper addition.
  ④ As the copper content in the black heart malleable cast iron increases, the tensile strength becomes somewhat high and the elongation, somewhat low, but the hardness does not almost change.