Director & Managing Executive Officer Osamu NOMURA

Eishi IIDA

Dan LARSON, Takayuki SUZUKI, Asish K SINHA and Elizabeth BORGES

Atsuhisa IIDA, Hiroki YOSHIOKA, Masato HASHIMOTO and Minoru SUTO

The Multi-Hole Plug (MHP), a type of a bottom blowing tuyere brick used for BOF steel making, contains many slender pipes which are closely aligned in a MgO-C brick. When we observe used MHP bricks, we often recognize they have cracks parallel to the hot faces, which suggests that if we could suppress the cracking, the performance of MHP bricks would be improved. Conventional thermal spalling test methods such as a dipping test into molten metal were not suitable for evaluating the MHP bricks because cracking usually occurs along the direction of the pipes. We developed a new spalling test method using a panel of spalling test equipment in which restraint against MHP monoblock and partial cooling of the core brick of an MHP were introduced. We conducted computer aided FEM analysis and estimated when the cracking occurred in the new spalling test procedure.

Naohide HAMAMOTO, Koji MORIWAKI and Masanori OGATA

Slide gate plates used for the continuous casting of molten steel are made of Al2O3-C materials, and decarburization of the material causes damage of the plate surface during casting. Therefore, it is important to suppress decarburization in the molten steel in order to improve plate durability. The bonding texture of the plate materials is reinforced by the metal additives. The effects of Si and Al addition on the reaction between plate materials and molten steel were investigated experimentally. Based on the experimental results, new plate materials were developed and showed good performance in actual use.

Masakazu IIDA

A numerical model describing blast furnace taphole drilling was established. The calculated results reproduced variations in the drilling rate of the blast furnace taphole well. By using the model, deceases in drilling rate caused by the increase in Young＇s modulus of taphole mix or deteriorations of drilling equipment performance were successfully calculated. Moreover, as a result of the simulative calculations for the sudden interruptions which occur during drilling, it was verified that the cause of the sudden interruptions is difficult to explain only by taphole mix sintering.

Masafumi NISHIMURA, Hisaharu SASAKI, Shigefumi NISHIDA and Makoto NAMBA

Alumina-magnesia castables are widely used for the working lining of the steel ladle. In recent years, there is an increased tendency for a more severe load on the materials, and there is a need for long life materials.
In general, alumina cement is used for ladle castable as a binder, and so, there is a limit to the improvement in performance like corrosion resistance because of the CaO component. Therefore, in this study, we examined the application of non-cement binder, and developed a new castable which has excellent corrosion resistance and spalling resistance.

Koji ASAKAWA and Toshihide YUMOTO

Peeling of tundish castable along with coating material is one of the tundish wear factors. It is generally caused by slag penetration in the castable. There are two methods of suppressing slag penetration which utilize both chemical and physical controls. One is to increase silica content in the castable and the other is to densify the castable.
However, increasing silica content decreases corrosion resistance and the water content cannot be reduced to make castable denser because the current water content is almost minimum.
Our newly developed ＂Ultra-low-water castable＂ with 4.8% (mass fraction) water content and applies spherical grains and has similar flow ability to the conventional one with 6.0% (mass fraction) water content. The new castable has a significantly low porosity, which results in the suppression of slag penetration and extended service life.

Yuki NIIYA Masatsugu KITAMURA

Taphole mix with coal tar is likely to raise some issues due to residual volatile matter. By adjusting the grain size distribution and changing the binder, we have developed a taphole mix with good volatility characteristics. This new taphole mix can harden in a shorter time and form a more closely packed structure.

Shigefumi NISHIDA and Masafumi NISHIMURA

We have developed high performance alumina-magnesia castable for the steel ladle. Features of the developed material and actual furnace application results are described in this report.

Natsumi HIGASIKAWA

Silica castable CST-K57 was developed as a substitute for fired silica brick linings. In our tests, CST-K57 exhibited excellent high temperature characteristics, similar to those of fired silica brick. In particular, the thermal shock resistance of CST-K57 was superior to that of silica brick. It has been concluded that CST-K57 is applicable as a replacement for silica refractory linings in various industrial furnaces.

Hiroyuki MORI and Hiroaki MORII

A new high-temperature glue which hardens quickly and adheres well has been developed. When the new glue was used for installing a gasket on the tip of the ladle lower nozzle, the gasket did not drop off while the ladle was moving from the ladle maintenance yard to the continuous caster until the lower nozzle connected to the ladle shroud. On the other hand, the gasket and glue were easily cleaned up from the lower nozzle after use.

Yoichi SASAI and Takafumi KOBASHI

We have developed an original periscope system for high temperature furnace wall observation. The advantages of the developed system are taking high quality pictures, operating convenience, and operation time saving. These advantages were achieved by adoption of new technology.

Masayuki NIHEI, Hitoyoshi KINOSHITA, Kyoichi MORISUE and Katsushi KOSAKA

We carried out large-scale remodeling on the manufacturing lines of No.3 manufacturing Section of Okayama Works, for the purpose of improving the productivity of the furnishing processes of SV plate and nozzle refractory production. We changed the layout of the facilities in order to minimize the transportation distance of work-in-process goods. We introduced new facilities and modified old facilities such as quick electric dryers for drying the surface coating of SV plates, a new dryer for drying steel casing mortar, an additional furnishing line, an automatic shelf and an express processing line for small lot production. At the same time, the welding work place was moved from the outside vender＇s plant to the same location as above-mentioned facilities in our plant. As a result, the productivity of the furnishing processes was improved by approximately 20% in 2012 compared to that in 2010 before the remodeling.

Kazuki IGAMI

We have developed adhesives which harden at room temperature with firm adhesion strength for a wide temperature range from room temperature to 1600℃. The new adhesives are good for the work environment because it has low odor regardless of nonaqueous type and also water can be used for washing tools. It can be used for the fixation of refractories with which water kneaded mortar cannot be used.

Atsushi MAKIYA, Masahiro YOSHIKAWA and Kimiaki SASAKI

Our SNB is a silicon nitride based composite ceramiccontaining hexagonal boron nitride. It has both the superior mechanical characteristics of Si3N4 and superior thermal spalling resistance and machine workability of BN.
The properties of this material are controllable by changing the amount of BN. It is also easy to machine. By utilizing these characteristics, the applications as heat-resistant materials are spreading.

Hajime SUZUKI, Mitsukazu ANDOH and Hiroshi MINAMIZONO

Natural Allophane is a unique clay mineral existing in volcanic ash soil. It is defined as noncrystalline clay composed of alumina and silica a ratio of 1 to 2. Allophane is generally a hollow sphere of which the diameter is 35～50Å with pores of 3～5Å. The characteristics of Allophane have not yet been fully defined which means it still has enormous potential. Sketchily speaking, the significant characteristic of Allophane is the retention capability of water molecules, organic acid, and various ions. This characteristic is related to the pore size of the molecules, the void among the molecules, and the change in electronic charge according to the pH. We are producing powdery refined high purity Allophane (product name: SEKADO-P1, Allophosite). This product has been and continuous to be widely used for deoxidation, decolorization, desiccation, and as an additive agent for fermentation nutrient mediums of antibacterial agents. The Allophane we will introduce
here is powdery Allophane which has been adopted for makeup base creams.

Rokuro MAEDA and Toshikazu SETOGUCHI

Silplate® is a revolutionary structural insulation fiber board for use as back up insulation for the molten metal process. The main performance advantages of Silplate® structural insulating board include

• High temperature capability
• Low thermal conductivity
• Excellent mechanical strength
• Dimensional stability