The dry wear of cast iron with flaky and nodular graphite structures was investigated by the amsler’s type testing machine. In these test, the surface of the specimen was repeated rolling accompanied by small amount of sliding. The experimental results showed that the rate of wear is very small at the starting period of the test, but increases after some running. The rate of wear of nodular iron is less than that of flaky graphite iron and the running period for the wear increasing is longer than the former. The decrease of flaky graphite size and the increase of graphite number in cast iron are not desirable for the promotion of wear resistance, but co-existence of quasi-flaky graphite is not so much affected to the wear properties of nodular iron. As the increase of wear after some running is attributed to the fatigue damage of the surface, deep pitting and numerous cracks are observed. The upper specimen in the test suffers under tensile stress on its surface up to the rolling contact owing to the slow speed of revolution, and the lower specimen under compressive stress on the contrary. So, the former specimen is more to fatigue than the latter. In the combination of specimens with different types of graphite structures, there is more difference in the rate of wear than in the combination of the same type of the structures according to the difference of strength between the specimens.

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  Generally, gas burner and oil burner are thin gray iron castings.
For machining and boring of burner hole, thin iron castigs should contain high corbon and silicon, and its structure is preferable to be coarsy flake graphite.
Even in normal combustion, gas and oil burners are exposed to high temperature up to 500°C, and also exposed to atomospheric gas which contains a considerable amount to carbon monoxide, carbon dioxide, and sulphur.
Under these conditions mentioned above, thin iron castings for gas and oil burner has much defects and problems for corrossion and growth.
We have surveyed most dependable iron castings for a year to solve these problems to increase corrosion-resistance and to prevent growth.
For testing sample, commercial thin gray iron castings, meehanite metal, ductile cast iron, malleable cast iron, low alloy cast iron, and aluminized cast iron were used.
As to the heat-resisting property, these samples were tested in an atmosphere of mixed town gas, and on the other hand, these samples were also tested in air and in the atomosphere which contains much sulphur for the comparision.
Brief items of testing results were as follows:
  a) As to the heat-resisting property, ductile cast iron is most preferable, however, malleable cast iron shows the same or inferior property to gray cast iron.
  b) Alminized cast iron and those which contains high silicon up to 5% show excellent heat-resisting property.
  c) Micrographic section of samples heated in atomospheric air shows the thinest oxide zone, and those heated in the atomosphere of town gas and high sulphur content show a considerable thick oxide zone.
  d) Oxidation loss heating in the atomospheric air is the most, and easily to be scaled.

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  Previously a new high grade nickel base corrosion resistance alloy to hydrochloric acid which has been developed in Technical Research Laboratory Hitachi Shipbuilding & Engineering Co., Ltd. was reported. This new alloy is named HZ Alloy CL consisting of Mo 20-30, W about 3, Fe about 1, Cu about 1, Ti about 0.2 wt % and Ni balance, has a excellent corrosion resistance property to hydrochloric acid, good weldability and ductility.
  In this study, a casting experiment was carried out on this new alloy. Experimental results were as follows:
  1. The beinning temperature of solidification of the new alloy is 1,459°C and its finishing temperature is 1,443°C.
  2. The fludity of the new alloy is inferior to that of Hastelloy C which has good castability, but by selecting proper casting temperatares, good casting products can be obtained.
  3. Molder’s rule for wood pattern is 24/1,000.
  4. A casting impellor of the new alloy was producted with no casting defects. The impellor showed excellent corrosion resistance to hydrochloric acid in practical use.

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  The amount of expansion of casting solidifying by skin formation or in mushy state in sand mold was measured and causes of the expansion was investigated. The casting chosen for study was a sphere which was 6cm in diameter. It had a cylindrical riser of variable height. 99.99% pure aluminium, commercial aluminium and Al-3%Cu alloys were poured into CO₂ gas molds. Pure aluminium and the other two metals are typical of skin-forming and mushy metals respectively. For measuring the expansion of castings, the change of the diameter of castings was checked continuously against time.
  The results obtained were summarized as follows:
  (1) The total expansion of castings in this investigation during solidification in CO₂ gas mold was positively correlated to the static pressure of liquid metal.
  (2) It was shown that this expansion phenomenon depends upon the mode of solidification. Namely, total expansion is large in case of solidification in mushy state, while little or no total expansion was observed in case of solidification by skin formation.
  (3) No correlation was found detween the amount of expansion of casting and gassiness of metal or hardness of mold.
  (4) The causes of this expansion of casting during solidification are supposed as follows. The dimension of the inside of mold is first increased by thermal expansion of sand, so the diameter of casting solidifying in mushy state is forced to increase by the adherence between metal and mold caused by metal penetration. Static pressure of liquid metal will influence on the extent of penetration of liquid metal into the mold.
  After all, the authors are sure to have added something by this investigation to the basic knowledge on the causes of every kind of casting defect.

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