The shear stress data for L1₂ single crystals for more than 50 kinds have been already complied. The fact that the ternary additive is inevitable to facilitate the single crystal growth of Ni₃Al is rather fortunate for us, because its selection is widely different by individual workers, and this situation enables us to evaluate the effect of ternary elements on the plastic behaviour in Ni₃(Al, X) single crystals. Referring to the comprehensive data for polycrystalline Ni₂(Al, X), the solid solution hardening of the CRSS for octahedral slip at low temperatures and the positive temperature dependence of the CRSS for octahedral slip are evaluated mostly on Ni₃(Al, X) single crystals in terms of the effects of compositions including both the deviation from stoichiometry and the ternary additions, and the effect of orientations of the stress axis. Above the temperature showing the maximum strength, the behaviour of the CRSS for cube slip controlled by Peierls mechanism and the CRSS for octahedral slip controlled by viscous motion of dislocations are analysed in terms of the dependent variables of temperature, strain-rate, orientation and compositions. Comparison of the plastic deformation is also extended to other L1₂ compounds such as Ni₃Ga, Ni₃Ge, Co₃Ti and Pt₃Al, which exhibit a big contrast each other. Also pointed out is the areas where the future research and development will be needed.

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In industrial iron ore sintering, the raw material is heated in a reducing atmosphere and cooled in an oxidizing atmosphere. In order to study the effects of gas atmosphere in industrial sintering, small tablet specimens containing powdered commercial iron ore, limestone, quartz and kaolin were heated in controlled gas atmospheres to examine the effects of gaseous atmosphere, heating temperature and cooling condition on the formation of minerals in sinter. The results obtained are summarized as follows.
In the heating stage of laboratory sintering, with a decrease of partial pressure of oxygen, the magnetite content increases and hematite content decreases. The calcium ferrite content is found also to decrease at the low sintering temperature (1 210°C). However, at a higher sintering temperature (1 255°C), a medium oxygen potential (5×10^-3 atm) produces the most calcium ferrite. In the air cooling stage, magnetite may react with the silicate melt and oxygen to generate a large amount of columnar calcium ferrite.
A typical microstructure of the bond composed of columnar calcium ferrite, granular magnetite grain and glassy silicate in a normal industrial sinter can be simulated reasonably by heating a specimen to 1 255°C for 4 min in the gaseous mixture CO=1%, CO₂=24% and N₂=75% and then cooling it slowly in air.

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Raw mixes of iron ore sinter feed were prepared under a variety of conditions. The permeability of mixes before ignition and during sintering was examined using a conventional permeameter and a small instrumented sinter pot, respectively. The sinter pot consisted of a gas preheater and a sample bed 29 mm high so that pressure drop of high temperature zones could be measured precisely and easily.
As expected, the pre-ignition permeability of the mixes was related to the mean size of the granules which in turn was related to the amount of water used for granulating. The order of permeability of mixes having different moisture contents did not change during or after sintering. Late-addition of coke during granulation resulted in a higher pre-ignition permeability. During sintering, however, the permeability deteriorated considerably. Use of lager particles of coke or limestone resulted in improved permeability before and during sintering. The basicity and coke content of mixes had little effect on the permeability of a bed during and after sintering under the condition of constant total amount of flux (SiO₂+CaO).
It was concluded that the permeability of the produced sinter cake depended predominantly on the pre-ignition permeability, for mixes of the same ore type and the same total amount of flux. This suggests that some aspect of the structure of a bed of granulated sinter feed is preserved during sintering.

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For the fundamental investigation of degradation behavior of coke in the blast furnace, the experiments for the oxidation of coke with various gases were performed and the effects of characters of coke, particle size and reaction temperature were examined.
A mathematical model was proposed for the analysis of the oxidation behavior of coke. According to the model, the effect of structural change of coke particles by the gastification on the concentration of carbon and the effective diffusivity was considered. The experimental results well agreed with the calculated ones by the mathematical model.

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A numerical scheme has been proposed to describe the mixing phenomena in a gas stirred liquid bath. The liquid recirculation flow rate has been estimated by combining a macroscopic, steady state energy balance model and an empirical correlation to take care of the swirling motion of the plume. The numerical scheme combines the concepts of mixing with the recirculation flow within a series of well stirred reactors arranged in a closed loop. The number of reactors (M) that are to be in the annular zone and the residence time (Δt) of circulating liquid in each reactor have been found to be dependent on each other. For a given values of M, there seems to be a constant value of Δt and vice versa. Keeping Δt constant, the value of M has been found to be a function of bath height and almost independent of other operating variables. The predicted values of mixing time have been compared with the reported experimentally measured values. Circulation number has been estimated using the predicted mixing time and circulation time values. It has been shown that the model is useful in estimating mixing time values for the industrial vessels.

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A simulation model was developed for analyzing the ''roll-kiss'' phenomenon, i.e., a situation where the upper and lower work rolls contact each other in the roll barrel. As a result of the analysis, a theoretical method of providing taper on the work rolls was found. The applicability of the method was experimentally confirmed in a laboratory mill, and the following findings were obtained.
(1) The accuracy of the load of roll-kiss calculation by Hertz's equation proved satisfactory for the practical use.
(2) Analysis using the simulation model revealed two different configurations of roll-kiss.
(3) The experimental results showed that for both configurations of roll-kiss, it is possible to prevent roll-kiss, by giving work rolls the optimum taper predicted from the simulation model.

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The effects of cold-rolling and annealing processes on texture and plastic anisotropy of copper-containing austentic stainless steel sheets were studied. This study has shown that a cold-rolled and annealed sheet with improved drawability can be produced without annealing aftere hot-rolling. The improved drawability was attributed to the strong texture around (112) [111] orientation. On the other hand, a cold-rolled and annealed sheet with low earing percentage and reasonable drawability has been obtained by the use of a proper combination of intermediate annealing and rolling reduction in the second stage cold-rolling. The rolling texture of this copper-containing austenitic stainless steel cold-rolled at room temperature consists mainly of (112)[111], (110)[001], (146)[211] and (110)[112] type orientations. The annealing texture of this steel is composed of (112)[111], (123)[111], and (113)[332] type orientations. The 45° ears observed in the cold-rolled and annealed sheets may be associated with the texture concentrated around (112)[111] and (123)[111].

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To clarify the Bauschinger effect behavior in a dual phase steel and the influence of strain again on it, tension-compression tests were carried out using a Mn-V low alloy steel. This steel shows extremely large transient softening and considerable amount of permanent softening. The strain againg at 448 K has been found to diminish the transient softening but to remain the permanent softening. The anistropy in magnetic coercivity in plastically deformed specimens was measured and has been considered to be related with the long range internal stress (back stress). The relationship between the back stress and the magnitude of the permanent softening is discussed.

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An investigation on the γ/γ' phase equilibria with particular emphasis or γ solvus is carried out in ternary Ni-Al-X systems with X being one of the VIA transition metal elements, Cr, Mo, or W. Differential thermal analysis (DTA) is employed as a key experimental technique, which is not very common to be used for the determination of phase boundaries. It is superior to the conventional methods because γ solvus surface with respect to ternary composition and temperature is readily obtained. The results obtained in each ternary system seem to be consistent and accurate, by which a large discrepancy is in many cases pointed out upon comparisons with the information reported in the past. An advanced analytical method, SEM-EDX, not only confirms the results obtained on γ solvus but also provides solid evidences for the occurrence of a four phase equilibrium in Ni-Al-Cr and in Ni-Al-Mo systems which is suggested by the results of DTA.

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A new technique for estimating the pH of concentrated aqueous solutions in equilibrium with high pressure H₂S and CO₂ at elevated temperature was proposed. Based on the thermodynamic investigation for solution properties, the following equation was obtained.pH=-logγ_H+{(K_{1, H,} K_{H, H,} P_H2S/γ²_±H2S)^1/2+(K_{1, C,} K_{H, C,} P_CO2/γ²_±CO2)^1/2}The physico-chemical parameters in the equation were calculated by PBILC (Principle of Balance of Identical-Like Charges) proposed by Cobble et al. or assumed to be identical with those for HCl+NaCl aqueous solutions. The calculation of the pH of high temperature and high pressure sour environments was facilitated by the of this equation.
A Nb-doped TiO2 semiconductor electrode of n-type was found to be suitable for the measurement of the pH of the environments; no interference from NaCl, H₂S and CO₂ occurred. The measured pH values agreed well with those estimated by the newly proposed technique at the temperatures up to 473 K and at partial pressures of H₂S and CO₂ up to 4 MPa. It was ascertained by pH measurements for HCl+NaCl aqueous solutions at elevated temperatures that the assumption made for physico-chemical parameters in the pH estimation was valid.

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The present work experimented with ladle desulfurization by powder injection under reduced pressure in comparison with under atmospheric pressure.
It was found that powder injection under reduced pressure provides a high stirring force, activates the entrapment of top slag and accelerates the desulfurization reaction involved.

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