It is necessary to obtain the intimate knowledge of desulphurizing power of manganese, which always exists in molten iron during the iron and steelmaking processes. However, it should be pointed out that whilst many studies on the desulphurizing power of manganese had been established, there was no good agreement in their results perhaps because little attention was given to behaviour of sulphur in liquid iron.
Because recently the activity of sulphur in liquid iron containing various alloying elements had been determined, the authors tried to study the equilibrium between manganese and sulphur dissolved in liquid iron and to ascertain the desulphurizing power of manganese on the standpoint of sulphur potential. On this first report, the Mn-S equilibrium in carbon satuated iron was determined between 1200° and 1500°C.
The results obtained were in good agreement with those of W. Oelsen. It is noteworthy that the results suggested the possibility of decreasing sulphur content of pig iron containing more than 1% manganese to be useful for steelmaking by lowering the temperature to about 1200°C. Such effective desulphurizing power of manganese was ascribed to high sulphur potential in liquid iron. Assuming the activity coefficient of sulphur in these Fe-Csat-Mn-S melts was expressed thus, it was presumed that the values of fs were nearly constant at any temperature except in the higher manganese concentrations. The equilibrium of manganese and sulphur in molten iron was shown as follows: and from experimental data it was apparent that the product [S%][Mn%] was also approximately constant at comparatively lower temperatures. Although the activity coefficient of manganese in such solution had not yet been determined, it might be regarded as constant in lower sulphur concentrations and carbon saturation. On this assumption, in the above range aMnS might be also constant and the apparent equilibrium constant K"=[S%][Mn%] was conveniently substituted for the equilibrium constant K and written. and then the following thermodynamical data were obtained,
Compared the data of carbon solubility in these experiments with those of Fe-Mn-C melts, the effect of dissolved sulphur on carbon solubility in liquid iron were discussed. In lower sulphur concentrations, the following equation given by Turkdogan et al. might be applied, where ΔNSC was the atom fraction of carbon which was displaced from carbon saturated solution by dissolved sulphur and NS was the atom fraction of sulphur in Fe-C-S melts.

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On account of the special features of charcoal pig iron that was described in the previous report (Tetsu-to-Hagané, Vol. 43, No 4, 1957, p. 444), it is used for producing chilled iron roll. Heretofore such special features have been considered to be owing to the gas contents, and so scarcely investigated with reference to the thermal factors.
Because the author considered that it had reference to the thermal factors, the following experiments which had been hardly tested were carried out:
1) Determination of the heating and the cooling curves in thermal analysis:
2) Determination of the anomaloug specific heat value:
3) Determination of A1 transformation temperature:
4) Determination of thermal conductivities for various pig irons:
5) Determination of specific heat for the boron-treated cast iron:
From the above experiments concerning these factors (the anomalous specific heat, thermal radiation thermal conductivity), there were found distinct difference between the charcoal pig iron and the other pig irons.

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Refer to "Tetsu-to-Hagane" vol. 43 (1957), No. 4, p. 431.

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The relationship between the residual compressive stress in specimen, resulting from shot peening, and the fatigue strength of it is studied. Si-Mn steel specimens are polished to 000, peened with hard or soft (round or as-cut) cut-wire shots, and tested with the 200kgm Schenk type fatigue-testing machine.
Conclusions reached are:
1) Residual compressive stress distinctly improves the fatigue resistance of peened specimen, but the investigations into the numerical correlation between the former and the latter are left to be studied.
2) Hardness of shots has a meaning only in relation to the ability of causing residual stress in specimens, then the softer shot is not always inferior to the harder one; i.e., the hardness number of shot will take a clear meaning only after the hardness of the work to be peened is shown.
3) The use of as-cut shot has a reverse effect upon the fatigue strength of the work, and the existence of comparatively high residual stress caused in the work will not prevent the fatigue limit from decreasing widely, if the bulk of as-cut shots is applied in peening practice.

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It is well known that forging ratio affects on the mechanical strength of steel, yet a necessary forging ratio as structural steel varies with different kinds of steels and ingot size. The experiments herein introduced were made to clarify the effect of forging ratio on the mechanical strength of 13% Cr steel. Eight specimens were used which had various forging ratios from 1 to 73, and test pieces were prepared being taken from two directions (i.e. forging direction and the direction at right angles to it.).
The results were summarised as follows.
(1) Tensile strength was not affected by forging ratio.
(2) With increase of forging ratio, reduction of area and impact value increased to the forging ratio of 18 and then decreased slightly, however those in the direction at right angles to forging decreased considerably to 10.5 forging ratio and then increased slightly.
(3) At room temperature, variation of fatigue strength had analogy to impact value etc., however, at 400°C, it showed different tendency.

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Studies were made on the effects of adding Ti and B on Timken 16-25-6 alloy, heat-resisting steel for gas turbine materials. In this report, the influence of the addition of Ti and B to 16-25-6 alloy on the phecipitation phenomena were examined.
There were four grades of samples of chemical compositions (See Table 1). Based on 16-25-6 alloys, two of them included Ti, one of them included B, and another alloy contained both Ti and B.
Samples were melted in high-frequency electric furnace, cast into moulds, and forged to bars. Solution-treatment was operated at 1150°C or 1200°C for 1 hour.
Specimens after solution-treatment were aged at four degrees of temperature, 700°C, 750°C, 800°C, and 850°C, from 1 hour to 500 hours. Aged specimens were tested for hardness, and observed through microscope. Microstructure was prepared by (HCl, HNO₃, glycerine) etching solution and other selective-etching reagent.
With the sample #D1 (0.7% Ti) and #D2 (1.8 Ti), precipitation-hardening speed increased with rise of the aging temperature from 750°C to 850°C, but softening began at 850°C after about 75 hours aging. Maximum hardness appeared at 750°C aging. In aging process, precipitated particles, which appeared in the case of standard commereial 16-25-6 alloy's aging, and TiC would also be precipitated.
With the sample #D3 (0.085% B), precipitation-hardening velocity was lower than the sample #D1 and #D2, and it yet continued to harden after 500 hours even at 850°C. Fe₂B was found and other precipitated particles, which were similar to particles of commereial 16-25-6 alloy, were also found.
In sample the #D4 (0.19% Ti and 0.03% B), precipitation process ranked between #D1 or #D2 and #D3. Variaties of microstructure during aging were found as cqmbinations of #D1 or #D2 group and #D3 group.

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The silchrome steel has been widely used for exhaust valves in the motor industry. However, recent experience has indicated that the products of combustion of leaded petrols exerted a rather marked corrosive attack on it, and that when such petrol was used, a steel containing higher chromium should be used.
To investigate the influence of Si, Ni, C and Cr on the properties of 20% Cr valve steel, the authors measured the critical point, the sectional diagram, the quenched and tempered hardness, the TTT-diagram, the retained austenite, the dimensional changes, and the mechanical properties at elevated temperatures.
The results obtained were as follows:
(1) The critical point was raised with the silicon and the chromium content, and lowered with the Ni addition.
(2) The hardenability increased with the nickel addition, and decreased with the Si content. The TTT-diagram showed only the pearlitic transformation within any reasonable duration.
(3) The quantity of the retained austenite after air-hardening from 1050°C increased with the nickel and the carbon content. The silicon content up to 2.8% increased the amount of the retained austenite, then more silicon addition decreased this amount. This retained austenite decomposed at 550°C and resulted in the volume expansion.
(4) The full hardness was obtained by air-cooling from 1050°C, and the austenitizing temprature for obtaining the maximum hardness was lowered with the silicon content, and when the silicon content was as high as 3.3%, the steel was not hardenable.
The hardness after 44h. tempering at a temperature between 600 to 750°C increased with the silicon, nickel and carbon content.
(5) As the carbon content increased, the tensile strength increased. The impact value decreased at room and elevated temperature. The impact value was increased with the Si content up to 2.3%, then decreased with more silicon addition, and also the nickel addition more than 2.1% decreased the impact value.

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Today, applications of permanent magnet are increasing in various fields of industries.The magnet of excellent quality such as Alnico, contains a great quantity of rare materials such as Ni and Co. During the World War II, research of permanent magnet was concentrated on the discovery of substitutional alloy which possessed high coercive force without containing any rare metals. MT magnet was developed in the authprs'laboratory. This magnet is Fe-Al-C ternary alloy and does not contain rare elements. It has magnetic properties nearly equal to a middle cobalt steel, and possesses comparatively high coercive force of about 200 Oersteds.
In this report, the result of basic experiments on optimum composition and effect of additional elements to MT magnet were described. First, the specimens of Fe-Al-C ternary alloys containing various different quantities of Al and C were prepared to detect their optimum composition. The experiment showed that these alloys presented. the most superior magnetic properties in the region of 8.0±0.2% Al, 2.0±0.1% C, and its residual induction became more than 6, 000 Gausses, coercive force more than 200 Oersteds and energy product more than 0.45×10⁶ Gauss-Oersteds. Moreover 13 kinds of metals including Si, Mn, Ni, Co, Cr, Sn, etc. were added to the basic ternary alloy, and their effects on the magnetic properties were investigated. Addition of small amount (0.5-2%) of Cu, Sn and Ni gave a good effect on magnetic properties. These elements, however, if added more than 3%, would come to unfavourable effect on the magnetic properties. It was appreciated from Fe-Al-C phase diagram of 1200°C section that the range of optimum composition lay approximately along a "tie line" in the γ field closed by γ+K or C field.

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A thermodynamic study was carried out on the equilibrium of the reactions C+Ti=TiC (s) and Ti+N=TiN (s) in a cast iron melt containing 4% C, 0.25% Ti, 0.03% S, 0.008% N, and 0.002% O under some assumptions. The formation temperatures of TiO₂ (s), TiO (s) and TiS (s) in the same melt were also determined by calculation. Ti in the form of TiC (s) was found to be about 80% of the total Ti content at 1400-1450°C. Though the result was not accurate, the behaviour of Ti in the melt during its slow cooling from about 1800°C could be apploximately estimated.

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Because the distillation method for determination of arsenic needs a very long time and is also tedious, the SnCl₂ reduction method has been developed to save the time required for the analysis. This procedure is most widely used for the determination of arsenic in iron and steel. In this process, SnCl₂ is added to a solution of AsO₄^3- in 8N HCl medium. The solution is heated at 90°C for 30 minutes and metallic arsenic obtained is determined by titration with N50 I₂ and N 50 Na₂S₂O₃. Inaccurate results are often obtained in the determination of arsenic by this technique, because of the high temperature, and the influence of titanium.
This paper reports the results of experiments using the SnCl₂ with 12N HCl medium at 45°C for reduction of the arsenic. In using this method the author has devised an improvement in technique which renders the method more certain.

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One may find in the various literatures and data, etc. the theories stating the influence which the gas composition in cast iron gives to its quality, the fact of which is too obvious to require any argument. But the results stated in the above data are quite different, lacking unity of method of determination for cast iron in comparison with the case of steel.
The authors made examination about the sampling method and, at the same time, compared and examined the 900°C vacuum-heating method with the vacuum-fusion method of carbon spiral type. And the following conclusions were found.
1) Regarding the H₂ analysis value, the data of the vacuum-fusion method mostly showed higher value and was more accurate than that of the vacuum heating method.
2) Also, in case of cast iron, the exhaust of gas from specimen was recognized at the room temperature. By holding the gas catcher using mercury under the condition of about 95°C temp, it was possible to complete catching for about 1/120 hours as compared with the case of leaving it at the room temperature alone.
3) In case of the metal moulding, 10mmφ mould was the best.
4) Instead of method of the metal moulding and mercury cooling the author tried and examined the method of silica tube suction and outside-running-water cooling and found that the latter was more simple, sanitary and economical. The silica tube having inside dia. of 8mmφ was the best. And the opaque will do, too.

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