On the Wear of Eutectic Graphite Cast Iron

The wearing phenomena of eutectic graphite cast iron was inspected by means of examining slide-worn specimens when treated with a lubricant, and then compared with pearlite cast iron in various ways. The wear of cast iron is so intricate that even if wearing condition is the same, the wear is variant as quality, structure, strength or stress, or sometimes hardness or roughness or the surface to be worn can not be equalized exactly. After completly observing them, wearing conditions which are mainly dependent upon pressure and velocity of wear are pre-determined and under these conditions the results are distinguished as follows: the wear of eutectic graphite cast iron is different from that of pearlite cast iron; initial wearing amount of eutectic graphite cast iron is not so apparent as that of pearlite cast iron and after a definite running the worn zone increases with running distance almost proportionaly.It is said hitherto that ferrite structural cast iron is inferior to pearlite structual cast iron regarding the resistant property of wear. The author has recognized this fact, but it can be said that this is dependent upon the wearing pressure and under a light load wearing the wearing resistance of eutectic graphite cast iron is much superior to that of pearlite cast iron. In the wear in the parts of sewing machine, several practical examples on this validity can be seen. Under the wearing conditions in which a part to be worn consisted of eutectic graphite cast iron and carbonitrided steel, various phenomena have been cleared and proved that eutectic graphite cast iron is more logical to use as cast iron for a sewing machine part in considering the resistance of wear, machineability and stress.