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Technical Report No.54 (2011)

Shinagawa Technical Report
No.54 (2011)

CONTENTS

Preface

Changes in Refractory Technology Seen in "Shinagawa Technical Report"

Director, Managing Executive Officer Yukitoshi Kubota

Special Theme

Development of CHISAKI VERTICAL KILN

Chisaki Corporation Tatsu Chisaki and Daizo Kunii,
Shinagawa Refractories Co.,Ltd. Keiji Ohnishi and Kenichi Matsubara

Abstract

A novel kiln has been developed by collaboration of the Chisaki Corp.

and the Hyundai Rotem Co., and installed in the Dangjin works of the Hyundai Steel Co. (500tpd).

At first, process of the development as well as the characteristics of the kiln are presented, and then structural elements of the kiln are briefly explained.

Performance data of the kiln is compared with those predicted theoretically, and characteristics of refractory are discussed.

Reports

Effect of Operating Conditions on Blast Furnace Trough ML Castable Deterioration

Kosuke Yasuo, Masatsugu Kitamura and Takashi Iida

Abstract

We investigated the change in the characteristics of metal line castable for the blast furnace main trough by two methods.

One was the analysis of samples which were used for a long term in actual furnaces, and the other was the analysis of samples after long heating times or multicycle heatings in the laboratory in order to better understand how metal line castable deteriorate in long term use and which factors had an influence on the deterioration of those castable.

The results showed that the SiC content in used castable decreased as the period of use became longer and heating-cooling cycle became more frequent.

This tendency was especially true in castable containing spinel.

The change in chemical composition observed in used castable was also observed in a castable sample after 15 cycles of heating at 1500oC for 3 hours and cooling in a laboratory test.

In this test, the modulus of rupture decreased and the apparent porosity increased, but the corrosion resistance did not change.

Influence of Blast Furnace Productivity on Corrosion Rate of Main Trough

Masakazu Iida and Kenji Suzuki

Abstract

In order to describe the variations in the corrosion rate of the blast furnace main trough from the view point of furnace productivity, a mass transfer model was proposed. In the model, the variations in productivity were taken into account as slag flow speed variations.

The calculated results were in good agreement with the observed data.

Thus, the accuracy of the alterations of trough repair schedule corresponding to the changes in the furnace production plan can be improved by utilizing the corrosion rate predicted by the model.

Quantitative Evaluation of Corrosion Resistance of Blast Furnace Trough Slag Line Castable Utilizing Crucible Corrosion Method

Masakazu Iida

Abstract

To quantify the corrosion resistance of the blast furnace (BF) main trough slag line (SL) castable, the castable crucible specimens, in which BF slag was put, were heated at various temperatures and times followed by chemical analysis of the slag composition.

The analyzed results were plotted according to Fick's law to evaluate the mass transfer coefficients (k) of the castable at each temperature.

The obtained k, which has physically significant unit of ms-1, indicates the corrosion resistance of the specimen. Furthermore, the activation energy of k was also evaluated.

Study of Weight Saving for Ladle Castables

Makoto Namba, Hisaharu Sasaki and Masafumi Nishimura

Abstract

In the steel making process, the reduction of heat loss caused by heat being absorbed and stored in refractories is highly effective for lowering molten steel temperature drop.

We studied to make ladle castables with low heat capacity and lightweight. Hollow alumina aggregate is used in alumina magnesia castables in order to reduce weight.

Application of the hollow alumina to alumina magnesia castable was examined, and an appropriate additive amount and grain size were found.

The effect of the heat loss reduction attained by the new lightweight castable was calculated with an actual ladle model.

Expansion Under Load Characteristics of Carbon Containing Bricks

Masayoshi Kakihara, Tsuyoshi Suwa and Hidenori Tada

Abstract

The thermal expansion rate under load was measured with a constant load being applied to the sample in order to investigate the volume stability and the state of stress caused by the thermal expansion of refractories under restrained conditions.

In this report, we improved the thermal expansion under load measuring method and presumed the amount of elastic and plastic deformation at high temperature for various carbon containing bricks.

The results of the measurements were related to the damage behavior of these bricks in actual furnaces.

Technical Information on Products

Refractories and Global Warming

Eizo Maeda

Abstract

Insulating and lightening refractories used in furnaces is an effective way to decrease heat loss in order to reduce CO2 emissions. In this paper, our company's CO2 emission reducing technology is introduced.

There were some problems with the former technology such as the life of the working lining decreased by the insulation of the back lining.

We are proposing new technology for increasing the insulation qualities and reducing the weight of the working lining so as to reduce heat loss and the maintenance, and also increased service life.

We recommend ECONOS, CALEAD and ALTIMA for shaped bricks.

They improve heat loss in actual use, for instance, the shell temperature is decreased several 10 oC while maintaining the same service life.

In addition, we propose the insulation castable LN-150 for unshaped requirements, because it doubles the service life of steel ladle covers. Moreover, as a conventional technology, insulation materials and furnace heat loss diagnosis are introduced.

High Performance Insulating Castable for High Temperature

Masahumi NISIMURA and Hisaharu SASAKI

Abstract

This report introduces two new types of insulating castables, brand name LN-150 (high strength type) and brand name LA-150-2 (low density and thermal conductivity type) which uses special aggregates.

LN-150 has the same thermal conductivity as conventional castable LA-155 and the same service temperature. LN-150 also has the same high strength as general alumina cement castable at the same time.

In contrast, LA-150-2 retains the same strength as conventional castable LA-155, with reduced density and lower thermal conductivity at the same time.

Observational Automatic Gunning Equipment (Auto-BX) for BF Shaft Repair

Yoichi SASAI, Junichiro OKUHARA, Takafumi KOBASHI

Abstract

It's useful to know the extent of the refractory lining damage condition before beginning BF shaft gunning repair.

Furnace operators will be able to plan a furnace repairs with adequate consideration.

Furthermore, it will be possible to judge if the repair attempt was successful.

Our company has developed the observational Auto-BX, which makes it possible to see the whole circumference of the BF shaft lining making it possible to see a more detailed view of the refractory lining than with conventional visual observation.

In this report, we will describe this equipment.

Porous Plug for Ladle Refining

Eiji Ishihara

Abstract

At a ladle refining furnace stand, gases are injected into molten steel through porous plugs mounted in the bottom of the ladle to stir the molten steel in order to promote homogenization the steel temperature and chemistry.

Features of our porous plugs ALP series and HSP series and improvements in the wear resistance during oxygen lance plug cleaning attained by using oxygen lance blowing tests are described in this report.

Development of New Unfired Slide Valve Plate Material

Yasushi Kawasaki and Shinji Adachi

Abstract

Standard materials for slide valve plates that have been manufactured by a firing process sometimes show poor performance when they are used under challenging conditions.

Therefore, Shinagawa has developed a new unfired material with high aluminum content.

This new material shows excellent performance and satisfies various customer requirements in Japan.

Lineup of Mold Powder Products

Yukimasa Iwamoto

Abstract

Mold powder has many roles in the continuous casting process, including thermal insulation of the molten steel surface, protection of the molten steel from oxidation, lubrication between the steel shell and the mold, and controlling heat removal in the mold.

Mold powder requires appropriate design given certain casting conditions. This report introduces our wide variety of mold powder products.

Dolomite Bricks Manufactured in China

Hiroshi Sugiyama

Abstract

We stopped production of dolomite bricks in June 2009 and have been shifting it to China.

Taking this opportunity, we would like to introduce the products manufactured in China.

Information on Products of Associated Companies

Isolite Insulating Products Co., Ltd. "FoamfraxR* Insulation for Furnace Lining Applications"

Koji Nakashima and Kazuhiro Hayashi

Abstract

Isolite started selling a fibrous monolithic material spray-lining for high temperature insulation in 2006 in Japan, called FoamfraxR which was provided by the U.S. Company, Unifrax Corporation.

FoamfraxR effectivly saves fuel and moreover has the advantages of faster installation speed than common materials, highly adaptable application to both veneering without anchoring and full-thickness with stainless steel anchors, lower airborne fiber levels and rebound loss than common spray-lining materials and longer-term storage than other water-mixture materials.

Teikoku Yogyo CO.,Ltd. "Information on Latest Products of Inorganic Paints and Adhesives"

Kazuki IGAMI

Abstract

This report will introduce the outline and features of all inorganic paints and adhesives including newly developed paints for the steel industry.

We expect that this paper will support various customers in many different industries to solve their concerns besides these applications we introduced today.

Nippon Rotary Nozzle Co., Ltd., "Eddy Current Mold Level Sensor (ECLM)"

Manabu Arai, Chikara Osaka and Masayuki Nakada

Abstract

The sensor Sis a key element among the components constituting the control system in the continuous casting process.

For this reason, stable operation, quality control and improvement in both quality assurance and refractory life can be achieved by the application of Eddy Current Level Meter (ECLM) with high measurement accuracy and short response time. This superiority of ECLM has been widely recognized and adopted at over 300 continuous casters in the world.