The hot permeability of aggromerates of iron ores (pellets, brickets or sinter) was measured. As result of the measurement, it was confirmed that the effect of the component particles was predominant at normal temperature, but it became minimized at 700-800°C by coagulation of particles each other. The correlation between the reducibillity versus porosity and permeability was studied. According to the author's investigation, this relation can be summarized the following equation of regression plane:
Where, R=reductivity, S=diameter of pulvekrised ore, P=porosity, and A=permeability in normal. At high temperatures, the size of pulverised ore is not so effective for permeability, furthermore the porosity and permeability of the different sizes were in negative correlation.

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Research on the fluidity or the viscosity of the molten iron is important for the purpose of iron smelting or foundry practice. These measurements are, however, difficult, because they must be carried out at high temperatures.
In these studies the flowing property was measured by the weight which flowed out through the capillary (2.3mm diameter, 15mm length) at the constant pressure of the molten iron. These capillaries were made of pure magnesia. The capacity of the flowability were determinred by the time required to let flow out a unit weight of mercury through this capillary at the constant pressure and temperature.
The effect of temperature, composition and degree of deoxidation of the molten iron were observed by various specimens which was melted in a high frequency furnace. The following results were obtained.
Here the time required to let flow out 0.3kg molten pig iron through the capillary was indicated by Z, that was nearly the reciprocal of the fluidity.
(1) The Z-T (temperature of the sample) relations of commonly used pigs were plotted in a almost linear relation and the inclination of curves were nearly similar. In general, the larger the percentage of[C]+[Si] was and the higher the temperature is, so the smaller the value of Z became, when other compositions of pigs were nearly equal. But some specimens show the other different properties. The values of Z were about 7.5-9.5.
(2) When 0.7kg Al per 100kg pig was added to the molten pig before sampling, the value of Z increased to 13-15 from about 8. By addition of 2.0kg ferro-silicon per 100kg pig, also the value of Z somewhat increased. When 0.5kg Fe₂O₃ per 100kg pig was added before sampling, conversely the value of Z decreased a little.
(3) When the percentage of[C]+[Si] in the molten pig was successively decreased to 4.3 from 5.3 by addition of steel scrap to the pig which was aelted in the furnace, the value of Z at each flowing test was decreased a little. This fact was opposite to the result of (1), but coincided with the result of (2)
(4) When the content of sulphur increased to 0.38% from 0.07% by addition of FeS to the molten pig iron, the value of Z increased only about 0.3.

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Out of the results obtained from report I and II (Tetsu-to-Hagane, Vol. 39, June 1953, 582-587; July 1953, 677-682, ) a sulphur balance chart was made for each heat. The average of these charts are shown in table 1. The whole amount of slag was calculated by using the amount of lime in slag as the base of calculation. From sulphur balance charts the relation between the amount of sulphur brought into the furnace atmosphere by the fuel and the sulphur pickup of the molten phase from the furnace atmosphere was studied, and it became clear that in the present working conditions sulphur in oil becomes to influence the amount of sulphur in steel bath when it exceeds about 1%.
The whole amount of slag must be more than 20t, that is, about 10·0% of the molten steel so far as desulphurization was concerned.
Correlation coeffioients between[S] scr. (assuming value of the amount of sulphur in scraps just before molten pig is charged) and several factors that seemed to influence this value and those between (S)/[S] and the basisty of slag, (FeO) and the fluidity of slag were calculated.
From the results of three reports the authors summarized the conditions and precautions to obtain good desulphurization in the basic open hearth furnace fired with oil and coke oven gas.

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When rolling seamless steel tubes by the use of Plug Rolling Mill, the authors measured both compression and bending forces acting upon Mandrel Bar of the mill, making use of Wire-Stain Gage. Through various data collected from practical operation of rolling tubes of 83mm. O.D., 3.7mm. thickness, and 7, 500mm. length, the following results have been obtained.
(1) Compression force is, in many cases, more powerful than mandrel bar's buckling load of 1st order, and therefore it is necessary for us to be provided with guides.
(2) Bending force is as powerful as compression force.
(3) In one case of our experiments, the stress acting upon the bar has reached, at one time, 25kg/mm² max. In order to fight against such a high stress, it will be necessary for us to use materials of high yield point and regulate the tube temperature down to max. 300deg. C under.
(4) Compression force is greatly effected by both rolling temperature and the reduction of tubes.
(5) From the calculations of buckling force under dynamical stress made by us, results which are, in general, in conformity with those of our experiments were obtained

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By the actual use of the Stiefel-Mannesmann piercer, the authors studied the effects of distances between top and bottom guide shoes made different as wide as possible upon the state of piercing phenomena from practical points of view. The results obtained were summarized as follows:
1) As the distance between top and bottom guide shoes increased while the other factors being kept constant, both the outside diameter and inside diameter of tubes became increased, while the wall thickness of tubes was kept constant, resulting in the decreased rate of elongation. However, the effects of these variations upon the practical operation were not so great to be taken into consideration. Nevertheless, when the distance between both top and bottom guide shoes was set wide open, the radii of both ends of the pierced shell became considerably larger.
2) The twist of tube surface increased.
3) While almost no variation was found in the main deformation, the swell of the circumference of the shell was conspicuously obserbed in the course of piercing operation, together with increace of the elliptic degree.
4) The average power required somewhat decreased, while the average amount of work required somewhat decreased.
5) While the axial moving speed of tubes during piercing operation somewhat decreased, the revolving speed of tubes somewhat increased. However, the variation of them was not so great. In effect, the pitch of locus on which the surface of solid rounds moved in the course of operation became somewhat shortened.
6) The pressing rate in the course or piercing operation somewhat decreased. But its variation was not so great. The pressing speed rate varied little.
7) The cracks that appeared on the inner surfaces of tubes tended to increase in number.
8) The cracks that appeared on the outer surfaces of tubes tended to increase in number.

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In manufacturing of the I-beam steel directly from the small ingot in one heat without billeting, they are often annoyed by the seamy defects on its flange edges. For prevention of the seamy defects, the authors began to study the various factors of their occurence in both steelmaking and rolling.
At first they investigated the surface deformation of I-beam by rolling the experimental ingot on which was drilled many small holes and found that the holes situated within 35mm from the corner of ingot became the source of seamy defects of flange edges.
So the subsurface blow holes of the ingot corners were assumed by counting number of them at adjacent chipping lines and the correlation between skinholes vs. seamy defects was found.
The experimental ingot was rolled on which was drilled thousand or more small holes with varying diameter and depth around the ingot and the length and number of artificial defects were measured.
Then the authors showed the effects of diameter and depth of artificial blow holes on the length and percentages of occurence of artificial defects.

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The infivence of manganese and copper on the mechanical properties of, the so-called S-H cast iron containing about 3·8% of carbon was studied in sand cast state and the following results were obtained:
1) The influence of manganese on the tensile strength and transverse strength of the cast iron was remarkable. The former was about 30kg/mm₂ and the latter about 1, 900kg when its manganese content increased over 0·8%.
2) The hardness of the cast iron increased also remarkably as its manganese content became higher.
3) No conspicuous influence of manganese on the defection was observed.
4) The influence of copper on the above mentioned mechanical properties of the cast iron was far less than of manganese.

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Melting and casting conditions necessary for production of the so-called S-H cast iron were studied and the following results were obtained in the scope of the present experiments:
1) The suitable melting temperature was 1350°C. to 1450°C., at which the cast iron melt was to be treated with the slag.
2) The suitable casting temperature of the cast iron melt, treated by the slag, was 1250°C. to 1300°C.
3) The basicity of the slag (CaO/SiO₂) should be over about 0.4.
4) The suitable amount of the slag was about 15% of the cast iron melt.
5) The suitable time of contact between the cast iron melt and the molten slag varied with content of the titanium oxide in the slag. The larger was the latter, the shorter became the former.

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The authors described the effect of carbon, silicon mangan and nickel on the aging of heat resisting steel of Ni-Cr system, in the previous report. (Tetsu-to-Hagane vol. 39, 1953, ) In the present investigation, they examined the effect of chromium, tungsten, molybden and tungsten plus molybden on aging of the same heat resisting steel of Ni-Cr system containing Ni 15%, Cr 20% as in the previous investigation.
As the results of these experiments, the authors gave most moderate contents of Cr, W and Mo, and then heat treatment for Ni-Cr austenitic heat resisting steel, concluding that: (1) The moderate contents of Cr were 20-25% for Ni 15-20% heat resisting steel, (2) W 4-6%, Mo 5-7% or W+Mo (3+5)%-(5+4)% were the moderate content for Ni 15%, Cr 20% steel, (3) Temperature of the solution treatment were 1200-1250C, and aging temperature were 750-800°C, and then aging time were 6-12 hours for Ni-Cr austenitic heat resisting steels containing W, Mo or W+Mo

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Quality control has been recently adopted in various fields of industry and now the authors gave a glance at it in their steel-making plant. Steel-making operations are divided into four parts; namely material preparation, meltng, refining and teeming, so some examples in each operation were shown.
1. Material preparation:
Pig iron and scrap steel were classified and the ratio of pig iron to scrap steel used was determined according to the quality of steel to be produced, in order to make succeeding operations easier.
2. Melting operation:
In the melting period, the most suitable carbon content at melt-down was aimed at to get the shortest heat time, which proved to be 0.55% C and 0.65% C for sheet and plate steel respetively in the 35t O.H.F. and 0.45% C (sheet steel only) in the 70t O.H.F.
In the acceleration of combustion by using oxygen through furnace-end burners, most advantageous method or "6-5-4 method" is being adopted. According to this method, oxygen flows into the furnace in the rate of 6m³/min, 5m³/min. and 4m³/min. for the three periods of onehour from the start of charging, 2 hours, therefrom and the remaining time till melt-down after that, respectively.
3. Refining:
To improve the weldability of the hull plate, a chart was prepared which showed the suitable weight of ferro-manganese to be thrown into ladle to make Mn/C in steel over 2.5.
4. Teeming:
In pouring, standard operations were as follows:
a) To decrease the brick and clay marks of ingots, silica mortar was used and newly lined ladle was avoided.
b) A wooden plate was floated over the molten steel in each of six molds around the central pouring well in the bottom pouring, in order to reduce violent metal splashes, which might cause scabs of ingots.

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試料を燐酸で分解し,硫酸及び水で処理した後,硝酸銀及び過硫酸アンモンを加え,煮沸してマンガンを過マンガン酸に酸化し,冷却後食塩を加え硫酸バナヂル標準液で滴定する.

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