The Rept. 1 reported the relation between buckles and properties of sand. In this time, properties of sand were still more investigated. Results obtained were as follows :
  (1) In the case of new Noma-sand, the relation between the water content and green strength showed the peculiar curve.
  (2) In order to determine the water content in green sand, the quantity and quality of clay should be considered.
  (3) The strength of clay as the binder, should be careful of how it is obtained by water together with the substantial strength.
  (4) One of the differences between new sand and the used is considered the variation of the adequate amount of water for added clay.
  (5) Clay of green sand is used in the condition of cohesive plastisity or other like characteristics.
  (6) The consolidate structure of green sand, by the increase of water, varies from the structure A to the B and moreover to the C. The maximum permeability is obtained in the B. (M. I. )

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    Recently a steel casting in green sand mould has come to popularize but in it penetration and burn-on are liable to grow. Researching these questions on the point of view of actual working, the author has investigated the method of their prevention.
    The main cause of penetration and burn-on is considered the point that FeO·SiO₂ or 2FeO·SiO₂ is formed by reaction of FeO produced on the surface of molton steel at the time casting and SiO₂ in moulding sand, and Fayalite produced as its result covers over granules of of moulding sand. Considering various factors about the method of prevention of penetration and burn-on for this cause, the author has researched influences of penetration and burn-on upon the mould strength of moulding sand, permeability, mould hardness, bentonite percentage, moisture and casting temperature in consideration of speciality of green sand mould.
    In the experiment, casting an automobile coupler yoke, casting steel for a rolling stock, in green sand mould, conditions of penetration and burn-on on the fixed surface have been researched comparing with each other. As for judgment of condition of penetration and burn-on, the author has researched how much percentage in test pieces cast in one charge has grown penetration and burn-on and has regarded its rate as indication of judgment. As its result, the author has recognized that the following three methods are effective on practice as the method of prevention of penetration and burn-on in a steel castings in green sand mould.
  (1) the method to ram moulding sand as strongly as possible in the limit of permeability.
  (2) the method to use moulding sand which contained moisture as little as possible and which increased the strength as much as possible in consideration of the connection among the strength, moisture and bentonite each other.
  (3) the method to lower the casting temperature.
    Among these three methods the author has taken the method (3) the most adequate in working. The author has applied regulation of the casting temperature for prevention of penetration and burn-on in actual working. As the casting temperature can be regulated by spoon-test at the time of tapping and by the killing time in laddle, considering.
    R=(Value of spoon-test (second)/Value of killing time (minute))
  and researching the relation between R and penetration and burn-on experimentally, the author has recognized that prevention of penetration and burn-on is executed most effectualy in the condition of R=4 or 5. As this method has been executed easily and brings the effective result, the author has been able to attain the expected object.

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  In 3rd and 5th reports published on the effect of wet air on hydrogen in the evolved gases, hydrogen less than 1% was detected in few cases, but generally hydrogen was not found in the evolved gases. In this present report, hydrogen supplied from a bomb was bubbled in molten cast iron, but scarcely analysed in the evolved gases. Only on the case of the addition of deoxidizing agent (Al) during hydrogen bubbling, hydrogen could be analysed in the evolved gases. However, when such molten cast iron was kept up in furnace for a few minutes, hydrogen was no longer detected in the evolved gases.
  In some part of the experiments, the evolved gases on solidification and the included gases of the samples cast same molten cast iron in a chiller were analysed. With the exception of the melting in which Al was added during hydrogen bubbling, hydrogen in the evolved gases was scarcely detected and one in the included gases amounted to 0.00002 to 0.00015 percent in weight, namely 1 to 8 cc 500 g.
  Considering the residual hydrogen in sample, it is comprehended that hydrogen was seldom or never detected in the evolved gases.

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  The acid or basic cupola practices were carried out to obtain the low carbon molten iron in a small cupola of 300 mm diameter.
  (1) The basic cupola can be operated without any serious trouble to obtain below 3 per cent carbon in molten iron by controlling the slag basicity and coke ratio like the acid cupola practice.
    Accordingly, cast iron of optional carbon content from higer to lower is possible to produce with large proportion of steel scrap.
  (2) Even the case of quenching in water among the best carburizing condition of basic cupola operation, the conclusions of Lownie was reconfirmed. (M. I.)

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