In this paper the author discusses the occurrence, origin, andremedy of flakes. He gives the results of a series of experiments as follows:-
(1) The cause of flakes is chiefly due to the grain size of primary crystals formed on the solidification of an ingot.
When the casting temperature is high, the primary crystals become coarse and the inner pertion of the in got will solidify much more slowly than the outer. if the temperature be high, the stress jnduced in the ingot during solidification should be great and weak parts should be produced around the coarse grain boundaries of the primary crystals.
(2) These weak parts will develope to hair crack called flakes by tensile stress in duced on cooling stage during annealing or on quenching operation.
(3) Flakes will be avoided with slow cooling after forging in case of thin material but this remedy is rot satisfactory, because it is impossible to avoid this defect completaly in case of thick material.
(4) If an ingot be cast in too low temperature, the crack like flakes will also occur and this defect will generally start from the minute non-metallic inclusions in the ingot.
(5) The reasonable casting process requesting high temperature melting and moderately low temperature terming is strongly recommended by the anthor to avoid both dirt and flakes.

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The "D steel, " containing about 1·5% manganese and 0·27-0·30% of carbon, is superior on the mechanical properties for the ship building material to the "High tensile steel (H.T.S.)" or "High high tensile steel (H.H.T.S.)" now used.
At the Imperial Steel Works, Yawata, they had experienced many difficult troubles in making this high quality steel owing to the defects of ingot. But after several months of earnest investigations they have succeeded to produce better material than the foreign "Ducol steel"
In this paper, appearances and mechanical properties of plates as well as relations between the ingot and the plate are chiefly discussed, also some factors relating to the open-hearth practice and the ingot making are pointed out.

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The bad coating of the tin-plates are due to improper pickling and tinning operations. But in many cases, the surface defects of the iron base are found none the less the grave cause to be counted for these failures.
The defects commonly seen on the surface of the iron base are those called "nebulous appearances, " the characteristic aspects of which are given in the shapes of seams, segregation, and recesses of which the embedded oxides have been pickled out.
The Writer has investigated these surface defects in every step of the operation i.e. from the ingot making to the finishing of sheet, and come to the following conclusions.
1) "Ingot seams" which are found in "cold cast" ingot carry oxides, blow holes, and segregations in the columnar crystal zone of the ingot.
when the ingot is rolled to sheet bar, the lateral seams run stretched in broken succession towards the direction of rolling of the sheet bar as thin pencil lines. And this bar is again rolled in its turn in cross wise to the former rolling direction. So these longitudinal seams are extended to the wide parabolical zigzag bands developing the inclusions in the seams. These defective surfaces are washed off by pickling, leaving the rough and heterogeneous appearances.
2) The thick dendritic structure grown in the columnar crystal zone of ingot is found in "hot cast" ingot. Such ingot of dendritic structure is liable to give rise to cracks in the ingot being reduced in the blroming mill, and the cracks, like ingot seams, cause bar mill seams and "nebulous appearances". While the ingot of dendritic structure is liable to form a very scaly sheet, and corrosion pits or sandy rough surface are formed after the sheet has been pickled.
3) Generally, the above mentioned defects in sheet iron can be prevented by merely removing all adhesives and defective parts, if possible, before the ingot or sheet bars are reduced in the mill. Now open hearth heats of stabilizing chemical analysis together with a close watch of the temperature at which the steel is poured, regulating the rate of casting, will help to overcome these defects.

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To measure the viscosity of molten metals and alloys the authors used the rotating cylinder method. To prevent the oxidasion of the molten metals, their surfaces were covered by carbon powder or nitrogen gas current; and just before each measurement the oxide filme on the surface was scraped off. Thus we could easily measure the viscosity of the molten metals.
The kinds of metals and alloys whose viscosity was measured are as follows:
1. Light alloys:- Al. Al-Cu, Al-Zn, Al-Cu-Zn, Al-Si Al-Cu-Ni, Al-Cu-Ni-Mg Silumin
2. Copper alloys:- Al-branze, bronze, brass, gun-metal, Mn-bornze
3. Cast Irons.
During the measurement of viscosity of aluminium and its alloys, the authors found two change points at 765°C; and 855°C; and their existence was further ascertained by thermal analysis and electric resistance measurement. The modification of Silumin seems to have some connection with the change at 765°C.
phosphorus, carbon, silicon and manganese improve the viscosity of cast iron in different degrees but sulpher injures it remarkably.

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