There are several means to be taken to provide against occurrence of longitudinal crack in ingot moulds.
One of them is to design a mould so as to be heated as uniformly as possible at the time of casting steel. The authors measured the temperature distribution of two or three moulds used at present in Toto Steel worke, in order to get some data inecessary to design a mould of new type. During this investigation, they recognized that the nozzle shape of runner brick has an unexpected effect on the temprature distrbution of moulds.And they discovered that using proper nozzle shape, generally speaking, flat shape, instead of usual round one, a very good effect on the temperature distrbution of moulds can be espected.

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Succeeding the first report, the subsequent results of ingot made of cast steel are reported.
The consumption of 600kg slab mould for the last 3 years was about 16.0kg/t steel ingot, and recently it has decreased to less than 15.0kg/t steel ingot. The optimum chemical compositions are as follows C Si Mn P S .40-.50.25-.35.60-.80 <.03 <.03
To prevent the growth of strain, ribs are very effectual, and suitable shape and thickness of the mould shall be more investigated.
About large moulds such as 2 ton ingot or more, to our regret, satisfactory results are not gained.

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Deformation of billet and peripheral slip between rolls and billet during the Mannesmann pie-rcing process were investigated. A billet, on whose surface a fine line mark is scraped paralled to its axis, was pierced or stopped on the way of piercing, and then twist of the fine mark was measured.
From the results of this experiment and of the first report, we could calculate the peripheral slip.
Results obtained are as follows:
(1) Twist of pierced billet surface is much less than the calculated value, as peripheral slip eaiste.
(2) Peripheral slip is maximum in the centre of pass and far less than axial slip as seen in the following table.

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Behaviours of Zirconium in steel are studied, the follwing effects are recognized:
(1) Acm points of high carbon steel are depressed by addition of Zr and Al points are inva-riable by being of Zr.
(2) Zr produces the secondary hardening in steel and its effects are accerelated by being togethei of silicon and chromium.
(3) Zr makes the austenite grains finer.
(4) Zr have ability spheroidizing the cementite in pearlite.
(5) Zr makes slow the softening speed on tempering of quenched steel, e.g. Zr have ability in-creasing the retarding effect to tempering.

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Influence of C and Si on the hardness, tensile strength and impact resistance of Cr-Mo cast steels (Cr 1%, Mo 0.35%) were investigated.
As the result of these investigation, it has been ascertained that the addition of Si to Cr-Mo cast steels gives a considerable influence upon the mechanical properties, that is, not only to improves the tensile strength, but also toughness such as elongation, reduction of area and impact resistance, and, that the moderate quantity of Si are 1% for cast steel contained with C 0.25-0.3%, Cr 1%, o 0.35%
The most suitable quantity of Si has an intimate relation with the C content, and the effective. limiting amount moves to the lower Si side according to the C content increases. The maximum tensile strength are obtained by adding Si up to 2% for 0.3% C Steel, Si 1.0-1.2% for 0.4% C steel and Si 1% for 0.5% C steel.
In case of tempering the impact value of Cr-Mo-Si cast steel shows the minimum values at 300°-400°C, that is, due to thefirst tempet brittleness. The Cr-Mo cast steel shows some inferiorities in mechanical properties as compared with the same forged steels, but the tensile strength in tempering at 600° or 700°C, are so improved as the forged special steels. In addition to these charaderistic, the Cr-Mo-Si cast steel is not recognized any significant difference in strength at the longitudinal and transverse direction.

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Some physical properties on white heart malleable cast iron were studied and the followingresults were obtained.
(a) Change of specific gravity in annealing:
The specific gravity decreases continuously by decarburization after graphitization had completed. This fact shows that traces of temper carbon remain as cavities, hence the decarburizedzone of malleable cast iron is not sound as steel.
(b) Tensile strength:
The tensile strength was discussed in dividing into two parts as graphitized zone and decarburized zone, the former streugth wae almost the same with pearlite malleable cast iron, but thelatter strength was lower than black heart malleable cast iron in spite of the structure is samesilicoferrite as black heart malleable cast iron.
(c) Embrittlemeut:
If silicon content increaase, there takes place so called embrittlement phenomena as known onblack heart malleable cast iron, but when silicou content decreased, this pheuomena was notobserved.
(d) Growth duriug repeated heatings and coolings:
Gray cast iron or black heart malleable cast iron takes place an apparent growth during repeated heatings and coolings, but the white heart malleable cast iron decarburized extensively didnot take place the growth notwithstanding some temper carbons are remained in ferrite.

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Although many investigations have been reported on the respective properties of Rimmed, Killed and Semi-killed steel, there are few papers which summarise and compare them.
In this report, authors explain and discuss the differences of properties and the use of these three kinds of steel, dividing their properties into following several items.
1) Difference in steel making process.
2) Character of ingot condition.
3) Segregation of chemical composition.
4) Mechanical properties
5) Some other properties
6) Uses

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In this paper, the results of studies on the mauufacture of art metal sheets of low carbon steel are shown, in comparison with the results obtained at two typical plants in Japan with different operation systems.
In the manufacture of art metal sheets of good quality, product quality is inainly influenced by the capacity of furnace, metbods of melting, casting and rolling, annealing, etc., and there remain many other problems which require further investigations. However, from the results of this study, the writer has set up an objective for melting operation.
Besides general rules for steel making which should be followed in operation, the following composition analysis must be aimed at: C<0.07 Si<0.07 Mn 0.25-0.35 P<0.020 S<0.020 Cu<0.20

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