An investigation has been done to get some knowledges of impact properties in nodular graphite and malleable cast irons. First the load-time curves in charpy impact test recorded, and then the processes of fracture were discussed from a view point of cracks referring their initiation and propagation.
  The results obtained were summarized follows :
  (1) At temperatures above the energy transition point (TrE), specimens can deform considerably after an initiation of crack at the notched edge before failure. The deformation is very sensitive to the temperature; the lower the temperature, the harder the deformation and finally it becomes almost zero.
  (2) Both initiation energy Wi-temperature curve and propagation energy Wp-temperature curve are the transition curves. In nodular graphite cast iron of ferrite matrix, Wi-temperature curve is considerably lower than that of Wp-temperature, and Wi is always higher than Wp at any temperature.
  (3) In black heart malleable cast iron, Wi-temperature curve is nearer to Wp-temperature curve than in nodular cast iron and though lower in temperature below TrE, Wp is apt to become higher than Wi above TrE. This relation berween Wi and Wp closely resembles to that of mild steel.
  (4) The effect of graphite particles on impact property is restricted to an outbreak of cracking not to crack propagation.
  The more sheroidal and the larger and fewer the graphite particles, the higher the Wi values and the transition temperature (TrD) of Wi-temperature curve has a tendency to move to low temperature.
  (5) The transition temperature (TrF) of Wp-temperature curve in malleable cast iron is slightly lower compared to nodular cast iron. It seems to be due to the difference of Si content dissolved in ferrite.
  (6) TrE of cast iron has an intermediate disposition between TrD and TrF same as in mild steel.

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  The graphite shapes in heat treated blackheart malleable iron is a somewhat aggregated graphite cluster and is commonly called temper carbon. There have, however, been few investigations into reasons or mechanisms whereby the spheroidal shape of graphite is produced in heat treated low Mn/S ratio irons. Therefore they are classified in three graphite shapes in this report, i.e., aggregated graphite, compact graphite, and spheroidal graphite. This paper reports the results of heat treating at 927°C and 1,010°C a variety of white irons of varying Mn/S ration and of two levels of silicon contents, and observations recorded during sample examination.
  Graphitization rates obtained showed that at a given silicon content, the rates of formation of the three graphite shapes grouped together. In all cases aggregated graphite required less time to form than compact graphite, and compact graphite less time than spheroidal graphite. It was also observed that the “incuvation time” for spheroids was greater than that of the other graphite shapes. Higher heat treatment temperatures and higher silicon contents reduced the time required to achieve a given percent graphitization, however, the higher silicon contents also tended to reduce the “compactness” of the graphite shape.
  The number of spheroids were greatest at low Mn/S ration. Lower Mn/S ration also tended to increase the “compactness” of the graphite shape, i.e., aggregated graphite at higher Mn/S, compact graphite at intermediate Mn/S, and spheroidal graphite at lower Mn/S.
  Nucleation of spheroidal graphite occurs at the sulfide-carbide interface. Growth of the spheroid is nearly always in contact with carbide until the later stages of graphitization. Contact with sulphide is maintained. Aggregated graphite appears to be nucleated at the carbide-austenite interface and to grow in the austenite with no direct contact to carbide after growth initiated.

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  The wear characteristics of CaCN₂ inoculated cast iron was studied and then the relations between the mechanical properties and wear characteristics were investigated.
  Results are as follows,
  (1) The higher the strength of cast iron before inoculation, that is, the lower the Sc value, the greater is the effect of inoculation in improving strength.
  (2) When Sc value is higher, the effect of CaCN₂ inoculation for wear resistance is less. In regard to mechanical wear limit little difference is observed between non-inoculated and inoculated cast irons, but wear loss of inoculated cast iron in oxidation wear range is less than that of non-inoculated one.
  (3) Using molten irons of different Sc values and different strength before inoculation, test pieces are prepared after inoculation in the same conditions, and the relations between mechanical properties and wear characteristics of them are studied.
  Results are; as the strength of cast iron increases, soxidation wear limit and mechanical wear limit are slightly improved, and as the hardness, tensile-strength, impact value and bending strength of cast iron increase, wear loss decreases in linear

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  In previous report, authors et al. observed on the fracturing process in cast irons by microscope. However, in order to research futher on the fracturing mechanism, as we consider to be necessary to find stress when fracture started in graplite, and meassured it and transverse rupture stress etc. Futhermore, percentage of matrix of fracturing surface was meassured and added to discussion because it is also felt that cross-sectional area of cast iron is a very difference depend on various shapes and distribution of graphite at the previous report.
  As a resuls, it is found that cast iron of high strength tend to heighten transverse rupture stress and stress when fracture started in graphite, and also it is not almost difference that percentages of matrix of fraturing surface in cast iron depend on tension, bending and impact, but they differ very depend on various shape graphites, effective cross-sectional area is to tend greatly to decrease in the cast iron of flake graphite. It is also found that strength of cast iron according to multiplication percentage of matrix of fracturing surface to strength of matrix. The degree of the fracturing unevenness differ by various shape graplites, when impact loaded it was smaller than the two others.

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  There were not a few papers published on the feeder of the casting, but they mostly concerned with the determination of a feeder shape and volume in relation to the volume ratio of casting vs feeder, the heat diffusivity of feeder surface, the measurement of the effective range of the feeder and the application of chill. Recently, W. Patterson densted that the feeding of the mushy metal might be different according to the mode of solidification of an alloy.
  In the present paper, the observations of shrinkage cavity and the mode of solidification were carried out by pouring Al, Al-Cu and Al-Si alloys into the mould and the pour out method. The ability of feeding what is called “feeding capacity”, was measured at the coexistent state of solid and liquid, and the relations between the feeding capacity and the mode of solidification were investigated and discussed, and also they were referred to the density which was measured. The result obtained were as follows :
  (1) It is possible to classify the mode of solidification by the results of the pour out method, the investigations of microstructure and shrinkage cavity.
  (2) The effect of feeding could be estimated by the feeding capacity to a certain degree though not entirely.
  (3) The effect of the mode of solidification to the feeding would also be considered from the results of the density measurement.

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