In the discussion of combustion and the quality control of the casting in the foundry, it is most important to estimate each component of the combustion product with its air ratio and their mutual relations.
  The author studying the mutual relation of each gas in the combustion of fuel, has introdueed the general equation of the combustion. It was analysed and projected on the plane, and the combustional diagram was obtained to express the relation between the component gases.

View full abstract

  Three varieties, green mould, naturally dried mould and skin dried mould, are commonly used for steel casting mould, all of which are composed mainly of silica sand, bentonite and water.
  Being natural product themselves, the bentonites for these moulds exhibit widely different properties because of their inherent characteristics.
  In this paper, the relations between bentonites and scab type defects in steel castings was sought after in a series of experiments on scab test piece as well as by the actual products from steel foundry.
  The results may be summarized as follows.
  (1) As for the testing method for scab type defects in steel castings by means of casting the test pieces, satisfactory results can be got from a scab test piece as shown in Fig. 1, because the test piece in this form can easily yield the scab type defects, with satisfactory reproducibility, and a mutual relation to scab type defects in actual medium to large steel castings is also established there by.
  (2) The classification and evaluation of scab type defects in the scab test piece can easily be done using a method presented in table 4, and photo. 3.
  (3) The scab type defects in steel castings can be reduced by using bentonite with higher liquid limit values for mould, as seen from the casting results obtained on the scab test piece and the statistical analysis of actual products from the steel foundry.

View full abstract

  In the previous report, the results of fundamental study of carburizing phenomena in molten iron with synthetic ashes and carburizing agents were described. In this report, sixteen kinds of coke calcined Japanese and foreign coals at 1000°C were used for carburizing agents with an intention applicable for practical use, and the relation between general properties of coke and carburizing phenomena were clarified as follows :
  (1) Until the saturation, carburizing time and carbon content of molten iron is in a semi-logarithmic relation and expressed in the following formula :
             C=a logT+b
    where C=carbon content in molten iron (%)
             T=carburizing time (min)
             a, b=coefficients varied with carburizing agents
  In the present study, two different types of carburizing phenomena were found. In one group, such as low coaking coal and oil coke used for carburizing, a, b are the constants during carburizing and it is described in a straight line of semi-logarithmic relation, but in another group, such as high coking coal and anthracite coal, a, b may be expressed in two different values respectively in the first and second period of carburizing.
  (2) A certain relation between the genaral properties of coke and carburizing phenomena can hardly be obtained.

View full abstract

  The behavior of the running metal head in a mould cavity was cleared up in recent investigations by X ray analysis.
  But even by this method the movement of each particles of metal could not be explained, which affected the temperature distribution and moreover the defects of the castings.
  This report is on the study of the running mechanism of cast metals which has something to do with the latter problems.
  The same materials, two or three different colored, were poured into a gate one after another, and these castings were cut after solidification to see the distribution of these colors.
  By this result, the movement of each particles at every moment and the process of filling up the metals in the mould cavity were clearly presumed.

View full abstract