The corrosion behavior of tinplate was investigated in acid food media correlated to ISV (iron solution value) and ATC value (alloy tin couple). The electrochemical potential of tin in ISV test solution was more positive than that of iron at low stannous ion concentration but with the increase of stannous ion concentration the galvanic-couple relation of tin and iron changes. ISV of tinplate is closely related to the corrosion rate of tinplate in air free acid media and also to the iron pick up in the solution where both potential of tin and iron are close.
The results of this study suggest that both ISV and ATG value are concerned in the galvanic attack of tinplate in spite of a little difference of their meanings.

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The effects of cold rolling, heat treatment and volume fraction of ferrite on stress corrosion cracking (SCC) behavior of duplex stainless steel have been studied with means of U-bend method in boiling 42% MgCl₂ solution. The main results obtained are as follows:
(1) SCC susceptibility of the solution treated material is small at about 50% α, but it has a tendency to be increased with either way of increase or decrease of α content from about 50% α. Solution treatment temperature resulting in abrupt increase of SCC susceptibility shifts to higher temperature with the decrease of α content.
(2) SCC susceptibility is increased by grain growth of α and γ that occurred with extension of holding time at solution temperature, and otherwise, by cold work in the case of the materials having much volume fraction of α.
(3) On aging at 475°C, the hardness is increased by spinodal decomposition of α. The crack resistance increases remarkably with the progress of aging in the case of materials having much α, and corresponds to age hardening behavior.
(4) In the case of heating at 700°C, SCC behavior of aged materials has not been made clear by U-bend method because of γ embrittlement.

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A new method to make hollow ingots was developed to produce cylinder-type forgings economically.
The key-point of this method is the structure of the core which, consisting mainly of outer and inner steel pipes and intermediate special refractory, can readily be constructed, set in the mold and pulled out from the ingot, and which enables to control the cooling from inner surface of the ingot, without such defects as inner-side cracks.
Large hollow ingots up to 200t can be made by this method with less segregation than that of conventional ingots and with such small porosities that close and diminish at forging ratio of about 2.
Thus, hollow ingots are utilized as materials for high grade forgings, such as pressure vessels, resulting in effective saving of production cost.
Compared with conventional ingots, hollow ingots have following characteristics of solidification;
(1) Total solidification time is short.
(2) Minimum solidification rate is high.
(3) Final solidification is not so rapia.
(4) Solidification from inner surface is slow.
Every feature in the internal quality of hollow ingot can be explained from these characteristics of solidification.

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Effects of addition of 5% of gaseous sulfide on the rate of reduction of iron oxide pellets were studied in temperature range of 800 to 1000°C with the following results:
(1) The reduction rate was greatly decreased with the additon of COS and H₂S respectively to CO and H₂.
(2) Analysis of the reduction rate based on the unreacted-core model and observation of the fractured surface of partially reduced pellets by using a scanning electron microscope and an electron probe microanalyzer demonstrated that the formation of dense FeS shells offered great resistance to the intraparticle diffusion of reducing gas toward the oxide core, thus greatly retarding the reduction of pellets, and that the partial penetration of the sulfide gas into the oxide core was also responsible to the decrease of reduction rate.

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The thermal-shock behavior of ZrO₂-CaO and ZrO₂-MgO pellets was investigated by immersing these pellets into liquid iron without preheating temperature or with preheating temperature. The moduli of rupture before and after the thermal-shock were measured by a three point bending technique. A good thermal-shock resistance was realized for partially stabilized zirconia containing 5 to 7mol% of stabilizer. The relationship between the thermal-shock resistance and the transport rate of gases through the cracks created during thermal-shock is discussed.

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Measurements were made of the total holdup, gas pressure drop and flooding velocities for flow through packed beds at low superficial velocities of liquid for various degrees of wetting between the liquids and solids.
Correlations for both static and dynamic holdup, and a flooding diagram which is valid for non-wetting as well as wetting flow, were obtained.
An instability of the bed, in which a transition from a stable to a fluidised bed occurred, was observed before the onset of flooding in some experiments. A diagram was developed to differentiate fluidisation from hooding in relation to the flow conditions. The diagram indicates that, in blast, furnaces, fluidisation of the coke bed is likely to start before the onset of flooding by the slag. The abnormal flow phenomena which could occur in the furnace are discussed in terms of the fluidisation of the coke bed in the dropping zone.

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An analysis of stress and strain during creep was made on notched bar specimens of austenitic 21-4N steel by finite element method.
A decrease in stress concentration at the notch root due to creep deformation occurred more rapidly in the notch-strengthened ductile steel with 36% of the grain boundary reaction (GBR) than in the notch-weakened brittle one of greater hardness (4% GBR). The equivalent strain at the notch root was smaller than that of a smooth specimen except in the early stage of creep in the ductile steel, but the former was always larger than the latter in the strongly notch-weakened one.
In the brittle steel, an increase in nominal stress enhanced creep deformation at notch root and consequently lowered the rupture time ratio of notched specimen to smooth one. Most of rupture life was spent in creep deformation before initiation of grain boundary cracks in notched specimen as well as in smooth specimen, independently of amount of GBR. Amount of plastic deformation necessary to initiate cracks was larger in the ductile steel than in the brittle one. This is considered to greatly affect the rupture strength of notched specimen.

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An experimental study has been carried out to investigate the peeling of coated metal caused by severe forming in hot dip aluminized steel sheet. The main aim of this paper has been to clarify the mechanisms of peeling and the relationship between peeling and forming conditions.
Experimental materials were aluminized steel sheets with a 1.2mm thickness and a coating weight of approximately 90g/m² in total both sides.
Peeling occurs when a compressive deformation is first applied and followed by a stretching deformation, as in the case of an outer wall of a drawn cup and an outer side of a hat-shaped bending. However, no peeling occurs in the simple deformation path, even after the sheet metal is broken. In actual press forming, peeling is liable to occur when the die profile is small and when redrawing is done many times, because peeling increases as the amount of initial compressive deformation and the amount of subsequent stretching deformation increase.

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The present paper is concerned with a study made with the purpose of clarifying the behavior of injected gas jets especially at the exit of a submerged orifice in liquid metal. Nitrogen was injected into a mercury bath through an orifice of 0.1-0.4cm in diameter located at the transparent vessel bottom. The gas-flow rates were varied from 0.05 to 4500cm³/s at orifice conditions. The highest gauge pressure supplied to the system was 20kgf/cm². Behavior of gas jets was observed directly through the bottom plate by using a high speed cinecamera. At low gas-flow rates the jet is shown to expand immediately upon discharging and form seemingly discrete bubbles. This behavior is called “bubbling”. With increased gas-flow rates, an apparent coincidence between the base diameter and the orifice diameter begins to occur over various time ranges. In these time ranges the injected gas is considered to leave the orifice as a continuous jet of gas. This phenomenon is called “jetting” and is found to occur in the sonic flow region. The change from bubbling to jetting takes place in a transitional gas-flow range. With increasing gas-flow rate jetting fraction increases and bubbling fraction decreases.

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The yield behavior of low-carbon sheet steel (0.07%C) has been examined under the strain rate of 10^-4 to 10^-1/sec at room temperature using an Instron type tensile machine. The stress-strain curves have been recorded by using a transient converter (8 bits×1024 words), since the response of an X-Y recorder is not sufficient for the measurements under high strain rates. The experimental results by the transient converter show that the upper yield points appear clearly before the crosshead speed reaches a given value of high strain rate. The transient converter is most desirable in order to observe the yield behavior under high strain rates. The results also show another break point of the dependence of the yield stress on the strain rate at the strain rate of -3×10^-3/sec, which is different from M. J. Manjoin (1944)'s strain rate, i.e., -10^-1/sec. The dependence of the yield stress, yield point elongation, and tensile strength on the strain rate in the range of high strain rate above -3×10^-3/sec is larger than that at lower strain rates. The yield stress is much more sensitive to the strain rate as compared with the tensile strength.

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Heterodiffusion of W into molten Fe, i.e., the diffusion of ¹⁸⁵W which is existing in a small quantity into molten Fe, in the temperature range of 1800 to 1970K has been studied using the thin layer capillary method. The diffusion characteristics determined from the experimental results are D_o=1.4×10^-3cm²s^-1 and E=62500±4500J mol^-1.
Homodiffusion, i.e., the dif fusion of ¹⁸⁵W existing in a very small amount into molten Fe-W alloy containing 23wt% W at 1865K was observed and the value of homodiffusion coefficient D=(1.9±0.08)×10^-5cm²s^-1 was obtained.
Furthermore, reactive diffusion which is the diffusion of W from solid W into molten Fe at 1865K was studied and a linear relation of diffusion coefficient with respect to the concentration D(c)=2.5×10^-5 (1-1.3c) was determined.
The experimental results obtained for reactive dif fusion were compared with those reached for heterodiffusion and homodffusion of W into molten Fe.

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