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Two types of lead-composite reinforced with steel fiber were prepared by a casting method; one was fabricated with solder-coated steel fiber, and the other the solder-ancoated steel fiber. The mechanical properties, plastic behaviors, and fracture modes of these composites have been studied, and the mechanical properties of the steel fiber have also been investigated on the variation of annealing temperature. The ultimate tensile strength of the composite with solder-coated steel fiber is in good agreement with the theoretical value shown by rule of mixture. However, the value of tensile strength of the composite with solder-uncoated steel fiber shows a slight deviation from the value of the rule of mixture. The stress-strain curves of all the composites can be divided into two regions, corresponding to crack initiation and crack propagation. The stress-strain curve of the composite with solder-coated steel fiber shows a continuity in the former region, however that of the composite with solder-ancoated steel fiber shows a discontinuity in the same region. In the case of composite having solder-coated steel fiber the fracture of steel fiber occurs necessarily at the fracture surface of composite, while in the case of the latter composite with solder-uncoated steel fiber the fiber fractures randomly in the composite. The variation in ultimate tensile strength of the steel fiber with annealing temperature consists of three stages; first stage ranged from 25°to 300℃ shows a nearly constant strength, second stage from 300° to 600℃ has a strength decreased rapidly with the increase in temperature, and third stage which is above 600℃ shows a nearly constant value of strength as in the case of the first stage.

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The principal objective of this investigation was to examine the role of adding elements such as molybdenum, niobium, tungsten and boron in the high manganese heat resistant steel in which nickel was completely replaced by manganese. The influence of alloying elements on the aging hardenability, elevated temperature tensile strength, oxidation resistance and creep rupture was investigated. It was found that the alloy whose composition is 16% Mn, 20% Cr, 0.2% C, 0.6% N, 3% Mo, 1% Nb, 1% W, 0.01% B exhibits good high temperature mechanical properties.

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The effect of the addition of 0.1% of copper, antimony, aluminum and beryllium to Ag-9% Cd alloys on the internal oxidation of the alloys has been studied. The effect of the addition of copper on the penetration rate of oxidation front was negligible. The addition of antimony, aluminum and beryllium reduced the penetration rate. The cadmium oxide particles became coarser by the addition of copper or antimony, whereas beryllium or aluminum made the oxide particles finer. The number of the oxide particles decreased with increasing distance X from the surface as X^(-3). The interfacial energy between cadmium oxide and silver was calculated to be about 45 ergs/㎠ at 903℃. The aging effect of the oxide particles was negligible even at 903℃.

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The study has been carried out on the electroslag remelting process(ESR) for the production of the high quality specialty steel. We constructed the ESR furnace of capacity 20 ㎏ ingot. Employing the furnace, several kinds of specialty steels such as S 45 C, SCM 5 and SUP 9 were remelted under different conditions for obtaining fundamental data. The results are; 1) The melting speed is proportional to the fill ratio, whereas the specific power consumption is inversely to it. 2) Nearly 80% of the sulphur content can be removed from the original electrode through the process. 3) The process is very efficient in removing non-metallic inclusions such as oxides as well as sulphides. 4) The slag in which calcium oxide being partly substituted for the slag of fluorspar and alumina is more effective in removing non-metallic inclusions. 5) The remelted ingot has sound homogeneous structure, exhibiting the improvement in ductility.

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Velocities of α and β-dislocation in undoped n-type InAs single crystals have been measured by double etch technique. The measured velocity-stress behaviors are compared with theoretical curves based on the abrupt kink model by Ninomiya et al. and the dragging point model by Celli et al. Our experimental results are found to be in better agreement with the latter than the former model.

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High Manganese steels containing 3% Nickel have been used for study of austenite grain size influenced by rolling and adding small amount of Vanadium, Titanium and Zirconium, when the specimens are annealed for various time at different temperatures such as 900℃, 950℃, 1,000℃ and 1,050℃. The results obtained are as follows; 1) With an increase of reduction by rolling, the coarsening temperature of austenite grain size was lowered and the initial grain size of austenite was refined. 2) The austenite grain size was refined by adding of 0.1-0.2% carbide forming elements such as V, Ti and Zr. The influence by adding V was pronouncing. On the other hand, that of Zr was least among the three elements. 3) Though these grain refining elements made the initial grain size of austenite fine, they didn`t significantly influence on the growth rate of austenite grain size below 1, 000℃.

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The equilibrium partial pressure of oxygen obtained by mixing CO₂ and H₂ gas is determined with (ZrO₂)_(0.85)(CaO)_(0.15) solid state cell by means of measurement of E.M.F. and the compound of SrO-Fe₂O₃ system is studied. The results obtained in this study are as follows. i) The oxygen partial pressure is determinable above 1000°K. The oxygen partial pressure by E.M.F. measurement is almost consistent with that which is calculated from equilibrium data when the flow speed of mixed gas is about 180cc/min, and the initial ratio of mixing(P_(co2)/P_(H3)) is nearly 1. ii) Sr₃Fe₃O_(7-x) phase is terragonal and single phase in the range of oxygen pressure:0.21∼10^(-15) atmosphere. According to decreasing oxygen contents of this phase, lattice constant of a_0 is increased and a_0 is decreased. iii) The composition of SrFeO_(2.54-2.74) is rhombohedral, single phase, SrFeO_(2.54-2.74) contains cubic and rhombohedral two phases, and SrFeO_(2.74-) is single cubic phase.

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In order to investigate the favorable condition of thermal treating and mass effect during the solidification and thermal treatment of grinding cast steel ball containing 1.61%C, 16.5%Cr, 0.50%Mo & 0.23%V, hardness and microstructure have been tested, and wear test was also performed. On the basis of this experiment, results were summerized as follows. 1) The thermal treated structure of grinding ball is related to mass effect during the solidification. 2) 60㎜ and 70㎜ ball are greatly influenced by mass effect. 3) The optimum temperature for austenitizing is 1050℃-1100℃

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Chlorination behaviours of ilmenite, magnetite, and titaniferous magnetite were investigated by means of a thermogravimetric analysis. Magnetite and titaniferous magnetite could be chlorinated readily, while ilmenite was rather difficult. The preferential removal of the iron from ilmenite by selective chlorination was extensively studied by measuring effects of carbon, chlorine flow rate, time, and temperature. Rate equation correlating the results as well as chlorination mechanism was also discussed.

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The greatest part of the steel produced in the world is teemed as rimmed steel. Therefore, the knowledge of the phenomena occurring during the solidification of this steel is most important. This study has been made of segregation ratio in 13t rimmed steel ingot and the results reported here are summarized as follows: 1) The maximum segregation as confirmed was appeared at the center part of 15-25% from the ingot top. 2) The maximum segregation is occurred by sulphur and the ratio ({max s/ladle s×100}) was 580%. 3) This results mentioned above are discussed referring to the experimental data on solidification in the core of rimmed steel ingot.

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