EFFECT OF THERMAL-CYCLING ON THE PROPERTIES OF GRAY CAST IRONS (Simulating Glass Mould Conditions

Abstract

A close scrutiny of technical literature, international stand :rds and actual practice reveals that a variety of materials have been suggested and used for glass mould f There has been considerable interest in this subject in recent times. A lot many variations of cast iron composition involving a annber of alloying elements have also been suggested as suitable glass .old materials. A number of desirable oharaeterstice are needed for any material to function, as glass mould viz. scaling resistance$ resistance to growth, adequate high temperature tensile strength and hardsa, excellent machInability, cheapness# easy availability ate . cast irons are known to . offer many of those desirable characteristics provided they are adequately alloyed with elements like Cr,Al, ,NiOCu,WfV etc. A further study of literature shown that efforts have not been ode to simulate glass mould Conditions on laboratory scale and study the proposed compositions in a systematic manners It was, therefore, aimed in the present Investigation to first design a suitable experimental, set-up to satistLetorily simulate glass mould conditions on laboratory scale. Subsequently It was aimed to investigate the behaviour of ordinary cast irons contafliftig relatively higher percentage of silicon under glass mould conditions. Ordiunry gray cast iron! coitt aitxina Za 58 art /. oilicon iroro subjected to thornai cyci$.ng treatment aorror~p c i dim to enact glass mould conditions upto 8000 cycles* in the prosomt t ork Itwas found that such gray irons Old a stabilizcd structure even then they are exposed to only 4,000 cycles, But these cast irons displayed poor coaling resistance then they tore exposed to 69000 cycles or moro. Room temperature property mo surom3uts revealed that the strength of base matrix or It' s hardness virtually reuaainm constant oven though the material is exposed to 8 0000 cycles.. it Iran found that this composition of gray Iron needs further allaying to IL prove it's coaling resi.stanae with regard to the glass mould operating conditions under questions