In this paper, it is introduced the surface temperature of warm-air pipe of 7^# blast furnace hot stove increases suddenly, the effect of surface air cooling is not obvious. With the observation by damping down and opening pore, it is determined that the firebricks inside the pipe are with a great area of collapse. According to the degree of collapse, the mode of pouring followed by grouting is used in this area for leak repairing. As a result, the surface temperature of warm-air pipe is returned to normal and such serious accident as burning through of warm-air pipe is avoided.

In this paper, it is summarized the operational experiences of heat preservation for silica bricks of Kalugin top combustion stove for 4 150 m³ blast furnace of Baotou Steel as well as introduced the conditions, requirements and matters needing attention in operational processes of heat preservation with external burner for silica bricks of top combustion stove, which provide references for heat preservation of top combustion stove during the overhaul.

In this paper, it is introduced the fault of leakage for gravitational dust collector and cyclone dust collector in the raw gas system of two 4 150 m³ blast furnaces of Baotou Steel. The reasonable treatment measures are put forward and implemented through diagnosis and analysis. The structure modification is carried out according to the actual installation of equipment on site to realize the stable operations of equipment, which plays a positive role in stable and trouble free productions of blast furnace as well as can be used for reference in the maintenance of related equipment for other blast furnaces.

The rare earth alloys are added in RH treatment to study the effects of rare earth on inclusions based on the production process of low-carbon and low-silicon steel. The results showed that the number of large-grained inclusions decreased and the proportion of short grained inclusions increased compared with those before adding the rare earth when the content of rare earth in steel was 0.003 2%~0.004 1%. Moreover, the morphology of inclusions in steel was changed from spherical, cluster and strip to spherical as well as the type of inclusions was changed from oxide to rare earth sulfur-oxygen complex and rare earth oxide.

The sublance technology is adopted in the production with 240 t converter of Rare Earth Steel Plate Plant of Baotou Steel for the first time. During the whole campaign of converter, the measurement efficiency of sublance decreases from 92.4% to 88.1% with the change of bath level. The solutions to use of sublacne equipment are put forward through analyzing and researching existing production situations and equipment conditions as well as the measurement efficiency of sublacne is stabilized at 92.2%~93.9%. With the steady improvement of technical indexes of sublacne, the quality of molten steel for LF supplied by converter is improved, which creates good conditions for producing high added-value products.

In this paper, it is described the cleanness of liquid steel is improved by studying and optimizing the technologies of each working procedure for steel making; in the vacuum degassing treatment with RH furnace, the yield of rare earth in products could reach 50% by further come-up of inclusions in the circulation of liquid steel and adding rare earth element in late stage of vacuum treatment; the effects of adding rare earth element to decrease Nb content and the original chemical composition without rare earth element on product performances are studied.

In the article, it is introduced that the production method satisfying the demands of spot welding technology, production and inspection for downstream customers is found through adopting reasonable composition design as well as controlled rolling and controlled cooling technological measures on the basis of meeting the product performances of S250GD + Z galvanized steel strip. As a result, the manufactured galvanized structural steel could be with batch production and such characteristics as good formability and weldability, which provide product design direction for the downstream spot welding products.

In the paper, it is studied the preparation of cerium hydroxide with cerium chloride solution as raw material as well as investigated the concentration of cerium chloride solution, quantity of H₂O₂ added, amount of NH₃·H₂O and the effects of reaction temperature on oxidation rate of cerium in cerium hydroxide to determine the optimum technological conditions. The results showed that the cerium hydroxide with oxidation rate of cerium greater than 97%, w(Cl^-)<0.15% and could be dissolved in HNO₃ solution was obtained when the mass concentration of cerium chloride was 120 g/L, amount of H₂O₂ was 0.7 times of mass of CeO₂, amount of NH₃·H₂O was 130% of theoretical mass and reaction temperature was at 50 ℃.

The TG22 hot rolled steel strip for oil casing is manufactured with the microalloying composition of medium C and Nb, the smelting with high cleanliness as well as reasonable controlled rolling and controlled cooling process. It is with good overall performances, its microstructure is fine and homogeneous ferrite and pearlite, the grain size is grade 12.0, banded structure is smaller than grade 2.0 and the sum of all grades for inclusions is smaller than grade 4.0. It is with high dimensional accuracy, good surface quality and strip shape. The overall performances of products are good and could meet the operating requirements of J55 oil casing. The products are with bulk sales and successfully applied as well as their quality is well-reputed by users.

In the paper, it is introduced the coil plate for hot rolling automobile axle housing with yield strength of 355 MPa has been developed with the component design of medium carbon and high silicon, controlled rolling and controlled cooling process as well as 2 250 mm hot continuous rolling production line of Baotou Steel. It is with good matching of strength and toughness as well as cold bending property to satisfy the use of manufacturers for automobile axle housing so that the small batch production and supply of coil plate products for automobile axle housing by Baotou Steel are realized, which lay the foundation for the subsequent development of steel grades with higher strength levels.