THE EFFECTS OF CALUCIUM HYDRIDE ADDITION TO GREY CAST IRON

Abstract

The authors studied the effects of calcium hydride addition to grey cast iron and the following results were obtained:
1) Spheroidal graphite cast iron could be obtained by addition of calucium hydride (CaH₂) in excess of 4% to a suitable molten iron (Swedish charcoal pig iron) covered with the flux of fluorspar.
2) When CaH₂ and fluspar were added without any other additions, it was difficul to give all spheroidal graphite structure, and always quasi-flake graphite was distributed in it.
3) More spongy blow holes occurred with higher addition of CaH₂ and fluospar, but when the spheroidal graphite structures occurred, most of the blow holes disappeared.
4) For suitable iron (Swedish charcoal pig iron), the addition of both 2% CaH₂ and Mgalloy was not so effective to decrease the amount of Mg which was necessary to make spheroidal graphite.
5) For the pig iron seemed to be oxidized, when blow holes appeared by addition of CaH₂, spheroidalization of graphite might occur by the same amount of additional Mg as to Swedish charcoal pig iron.
6) The effect of desulphurization was observed by addition of the CaH₂ spread over the molten iron.