A detailed description is given of a small-scale laboratory reduction apparatus which uses microcomputer control to achieve simulation of the gas and temperature profiles which occur in direct reduction shaft furnaces. The apparatus allows specific, fixed or continuously changing reduction conditions to be impressed onto lump or pellet samples to simulate the passage of an iron ore burden moving down the shaft of a direct reduction furnace. Results from initial experiments indicate that the course of reduction is very different to that observed in fixed gas composition reduction experiments and the quality of reduced materials is dependent on both the original oxide and the initial reduction temperature. The work has shown that there may be scope for adjusting the operational parameters of direct reduction furnaces to maximise the quality of directly reduced iron being produced from particular oxide burdens.

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The influence of alkalies on the blast furnace operation has been discussed from the data collected from the Iron and Steel Co., Helwan, Egypt. The stability of the alkali compounds formed in the blast furnace was calculated from the thermodynamic data. The model of alkali circulation in the different zones of the furnace, as a function of temperature is proposed. Statistical analysis of alkalies from the input and output materials was calculated and discussed. The effect of alkalies on the partition of manganese and sulphur as well as on the rate of coke consumption was investigated. The relations between the alkali loadings, the basicity and the efficiency of alkali removal by the slag were discussed. Mathematical relations between these different parameters were given and correlated.

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Pulverized coal is being used increasingly as a blast furnace injectant. It is injected into a blowpipe zone where spontaneous ignition and combustion occur by mixing with the hot blast.
A theoretical study is made on the ignition and combustion of injected coal particles in the blowpipe zone. The theory uses a simple combustion model in which diffusion of gaseous oxygen is dominant for the combustion rate. The derived results show the effects of coal properties and blast and injection conditions on the degree of burn out and the blast gas temperature at the tuyere nose. These results are compared qualitatively with reported experiments and reasonable agreement is obtained.
In spite of some severe assumptions used in the theory for simplicity, the present objective is satisfied, which is to provide preliminary information for optimization of the injection conditions.

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Continuously cast low Al and N steels have been developed as mild steels for bar and wire rod applications. Al content is controlled, using R-H degassing process, from 0.003 to 0.01% not only to minimize Al₂O₃ inclusions but also to prevent the subsurface blow holes in the bloom section. N content is also reduced under 0.003 % by the hard-blowing of LD process and shrouding during casting.
Compared with rimmed steel wire rod, this new steel shows better drawability and higher ductility of wire at the high speed continuous drawing. On the cold forming test the surf face and center of this steel has shown the higher ductility. At higher annealing temperature the, ferrite grain of this Al-killed steel tends to grow suddenly. B addition is effective to the prevention of the abnormal grain growth and brittle behavior of annealed products. Because of the high cleanliness and this segregation of continuous cast bloom, the size and amount of inclusions are smaller and hence the machinability of this steel is poor. Higher S content is desirable for improving it. In addition, the depth of carburization is relatively small. However B addition increases the austenite grain size and hardenability of carburized products.

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The bending theory of continuous beam has been applied to the analysis of bulging in continuously cast slabs. A simple algorithm was formulated to transform a through-thickness distribution of creep strain in a shell into the shell curvature, and equations were given for the analysis model of continuous beam with multi-supports. Simulations have proved that the model satisfactorily predicts the variations of bulging profile with multi-roll arrangement and the transitional bulging including unsteady fluctuations.

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In order to search for suitable technological schedule of hot strip mill, there is proposed an economo-mathematical model, in which production cost is a function of technological parameters such as threading speed, thickness of transfer bar and extract temperature from reheating furnace. The optimization of these parameters is performed to produce high quality strip with minimum production cost. The optimization code was applied for a hot strip mill in Bulgaria and also for one in Japan. The economical situation for production of hot strip differs much from each other in these two countries, and the type of hot strip also differs, but the code could output proper solutions. With the use of the code, a new rolling schedule, in which the transfer bar thickness decreased with length of strip, proved the possibility to reduce production cost and improve gage accuracy.

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Effect of adhesion strength on the Bendability was studied in a compositetype vibration-damping steel sheet which consists of two steel skins bonded with a viscoelastic resin. The adhesion strength of the damping sheet was evaluated in tensile shear strength (TSS); TSS values of the damping sheets used for the test were 6, 61, 126 and 148kgf/cm². U-and 90 deg-bend tests were adopted as bend formability tests.
It was found that the bendability of the damping sheet is closely related to their TSS, and it is improved with an increase of TSS. When the TSS is higher than 126kgf/cm², the bendability of the damping sheet is quite similar to that of conventional steels. On the other hand, when the TSS is as low as 6kgf/cm², the slip and peel-off between two skins were observed in the bend tests.
In the 90 deg-bend test, the damping sheet with TSS of lower than 61 kgf/cm² bend properties are different from the conventional steel. In large size of bend radius, bend angles of the damping sheet were larger than those of the conventional steel. However, in small size of bend radius, bend angles of the damping sheet were smaller than those of the conventional steel. These behaviors of the damping sheet are based by elastic property of the core resin.

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Three steels microalloyed with V, Nb and V & Nb were deformed by torsion at temperatures from 900 to 1200°C and over a strain rate range from about 10^-3 to 10s^-1. Within the experimental range covered, typical dynamic recrystallization type flow was observed in all steels. The dynamic recrystallization behavior was analyzed with a special emphasis on the transition from multiple to single peak flows. The grain size of the dynamically recrystallized materials was also measured, and it was able to present as a function of the Zener-Hollomon parameter, Z, without exhibiting any dependence on the initial grain size.
The transition condition of flow stress behavior could be reasonably expressed by Z, not as a unique value but by a range of Z values. Throughout the range, the transition of flow stress behavior occurred. The correlation of the flow behavior with the resultant microstructure was also considered.

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For the purpose o f expansion of the data analysis activities, a system named IDEA (Information DEsign Aid) has been developed to apply for quality control at Mizushima Works of Kawasaki Steel Corporation (KSC). The system consists of the three sub-systems: analysis support, database structure, and operation support.
The system is intended to be highly efficient and useful by providing a large amount of data storage in its items and volumes collected in the production lines, a sophisticated software easily accessible for a number of personnel at the terminals, and activities for supporting the computer utilization in routine and provisional jobs of the terminal users. The system has been found useful in reducing the workload for data collection and analysis and improving the analysis accuracy; this contributes to the efficiency not only in analysis work but also in various staff work.

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