Types Of Cast Iron Research Articles

Study of dry sliding wear of cast iron as a function of surface temperature

The dry sliding wear of flake and spheroidal graphite cast irons was studied as a function of sliding surface temperatures. The average temperature of the real areas of contact between the sliding surfaces (the flash temperature) and the mean temperature of the apparent sliding surface (the mean temperature) were considered. Wear tests were performed in air and vacuum on a pin-on-disc machine by rubbing various types of cast iron on Constantan, nickel and 17Cr stainless steel, and the flash temperature was measured by the dynamic thermo-electromotive force method. Variations of wear with sliding speed and applied load are explained in terms of the flash temperature and the mean temperature. When the mean temperature is below 400 °C wear reaches a maximum at a flash temperature of 300–400 °C and then decreases with further increase in flash temperature. Wear is low below 250 °C and is independent of sliding conditions such as speed, load, ambient temperature and atmospheric pressure. However, when the flash temperature approaches the melting point the wear depends strongly on the mean temperature and reaches a minimum when the mean temperature is below 400 °C. Seizure occurs with high wear if the mean temperature exceeds 400 °C.

Thermodynamics of microsegregation and influence of elements on structure of unalloyed and alloyed cast iron

Graphitizing elements in cast iron such as Si, AI, Cu, and Ni are subject to so-called ‘negative’ microsegregation during crystallization of primary austenite dendrites in hypoeutectic cast irons, while chill-forming elements such as Mn and Cr are subject in the same conditions to ‘positive’ microsegregation. This general rule is developed quantitatively and the theory of micro segregation of the components of cast iron is linked to the theory of graphitization. On this basis a new aspect of the thermodynamics of graphitic and non-graphitic iron alloys of the cast-iron type was worked out, using methods of geometrical thermodynamics developed from those proposed by Hillert in the early 1950s. A simple equation has been obtained which gives a relationship between the activity of components of ternary systems and the slope of the tie-line in the corresponding two-phase region of the phase diagram. The paper also includes the results of computations in the Fe-C-Si and Fe-C-Al systems. The results are analysed and compared with those obtained on the basis of relationships between the slope of eutectic lines and the angle at the summit of eutectic tie-line triangles.

Effect of the Electrode Temperature on the Spark Discharge IV

A study has been made on the influences of matrix and electrode temperature on spectrographic analysis of cast iron. White cast iron, ferritic gray cast iron, pearlitic gray cast iron, blackheart malleable iron, pearlitic malleable cast iron, ferritic spheroidal graphite cast iron, and pearlitic spheroidal graphite cast iron were used for the sample electrodes.The erosion and spectral line intensity of gray cast iron were remarkably higher than those of white, malleable or spheroidal cast irons. There was little difference between ferrite cast iron and pearlitic cast iron. These results show that the influence of matrix on spectrographic analysis depends mainly on the shape of graphite.When a heated sample-electrode was used, the influence of matrix on spectrographic analysis decreased. One working curve obtained by using sample electrode heated at 740°C makes it possibie to analyze all types of cast irons. The causes of the decrease in the matrix effect are thought to be violent oxidation and melting of the surface of the electrode, which homogenize the surface of diffecent cast irons.

Spheroidal-graphite cast iron as an engineering material: Properties and applications

Spheroidal-graphite cast iron is a fairly new material characterized by high strength, toughness and good casting and machining qualities. The mechanical properties of the conventional types of cast iron containing flake graphite are considerably imp

球状黒鉛鑄鐵の車輛用制輪子への應用

Spheroidal graphite cast iron has many good properties as an industrial material, because of its special type of graphite. Wear resisting properties of this material has been expected to be excellent since advent of spheroidal graphite cast iron. Especially, in a dry wear condition spheroidal iron is said to be superior to other types of cast iron. Much research on the wear properties this material has been made by many investigators in Japan but their opinions about wear properties of spheroidal iron differed from each other and various experimental results were obtained. Naturally, complexity of substantial wearing mechanism and diversity of experimental conditions of wearing tests caused these discrepancies. Accordingly, to permit the wearing properties of the spheroidal graphite iron to be clear, experiments should be made in practical conditions. In this report the authors compared the life of spheroidal iron brake shoes with grey iron brake shoes which had been attached to electric tram cars The results were obtained in which the wear loss by grey iron brake shoe was about three times as spheroidal iron. The authors also made brake tests with the same tram car using two types of cast iron brake shoes which were used in the wearing tests. In brake tests retardation curves were recorded by using a self-recording acceleration meter. From these retardation curves the friction coefficients between brake shoes and tires were calculated in various experimental conditions. Thus the brake·effects of these two types of cast iron brake shoes could be compared. The results were such that the friction coefficient of spheroidal iron brake shoe was larger than that of the grey iron shoes when car velocity was raised up to more than 43 kilometers per hour.

I. Report on Austenitic and Martensitic Special-Duty Cast Irons

The First Report of the Committee* outlined briefly the development both of high-duty cast irons used by engineers for their superior strengths, and special-duty cast irons used mainly on account of other properties. As a consequence of the war, a demand has arisen among engineers and users for further information on special-duty irons, which are being used both as substitutes for other materials in urgent demand and for new applications arising out of the unusual conditions now prevailing. The Committee therefore decided that monographs should be prepared for the purpose of providing engineers and users with information available, and the present publication covers two relatively new types of special-duty cast iron—the austenitic and martensitic irons. To avoid repetition in introductory statements relating to the character of these irons, the two monographs are prefaced by a description of the types of cast iron available, which it is hoped may prove generally useful as well as a convenient summary of the relationship of the two types to each other and to the other cast irons in general use.

Discussion on "The development of efficient methods in the foundry" at the Coventry Section of the Institution

MR. TWIGGER : In one thing I fully bear you out, and that is the number of developments which have come along during the past few years. It is a commonplace that in all the things of life, these last twenty-five years have probably produced more changes than in any other twenty-five years in the history of this country. That is most certainly true in the case of foundry work, and I speak more in regard to cast iron. It is bewildering when one thinks of all the special types of cast iron which have been introduced in recent years, together with the vast range which has opened up by the heat treatment of cast iron. One sometimes wonders where it is going to end.