抄録
On the basis of elemental studies reported earlier, several conditions for producing heavy duty cast iron in a practical cupola through hot-melting and inoculation were clarified.
1. To obtain hot melt beyond 1500°C throughout the operation, it is necessary to use the coke with ash content of below 12%, and to supply the air to the amount corresponded to the coke ratio.
When the coke having the ash content of 11% is used, the coke ratio should be 18% at least.
2. As the heat efficiency of cupola desecnds with ascending the coke ratio and the air volume, it is not so effective for raising the temperature of melt to increase coke ratio beyond a limited range. With increasing the coke ratio, however, the oxidation of melt is depressed and the effect of inoculation is secured.
3. The mechanical properties of test bars were improved very much as the silicon recovery becomes better ; namely, the oxidation of melt during melting becomes lesse.
As for their dependence on carbon and silicon contents, test bars with having the Sc is nearly 0.85, showed the most excellent results in transverse strength and diflection. Accordingly, to obtain the excellent heavy-duty cast irons, the melting operation should be such as to secure higher silicon recovery and higher carbon pick-up, aiming that the chemical composition of melt with Sc 0.85 or less.
4. When these cast irons are used as brakeshoes for electric cars, the amount of abrasion decreased 20 to 30 per cent compared as that for the ordinary cast irons.
