In the paper, the technical progress of ironmaking system of Baotou Steel is summarized and analyzed. It is thought that the technological breakthrough and innovation of beneficiation, sintering and smelting problems for special iron ore of Bayan Obo are fundamental guarantee for achieving the ironmaking production with high efficiency and quality, low consumption, long service life and environmental protection as well as technical support of great-leap-forward development for ironmaking of Baotou Steel.

The inheritance mechanism of rare earth element lanthanum in baiyuneboite during process of blast furnace ironmaking is studied by taking rare earth lanthanum as the object. The microscopic behaviors of lanthanum from slags to iron during process of blast furnace ironmaking are analyzed by thermodynamic calculations and experimental characterization. The results indicated that La₂O₃ in blast furnace slags could be reduced to LaC₂ during process of blast furnace ironmaking, and then LaC₂ is dissolved in molten iron and La is adsorbed by the oxygen functional groups on porous graphite so that the rare earth could be inherited to subsequent steelmaking processes, which makes up for the problem in traditional view that the rare earth oxides in blast furnace slags are difficult to be reduced during process of blast furnace ironmaking and cannot be inherited to subsequent processes.

The applications of elements are out of balance in the rare earth industry in our country as well as abundant lanthanum and cerium are surplus so that the applications of rare earth in steel are gradually heeded. In the paper, the research progress on treating steel with rare earth lanthanum and cerium at home and abroad in recent years are overviewed, which includes the effects of rare earth on purifying liquid steel, modifying inclusions and microalloying as well as design of deoxidation test for rare earth proves the feasibility of rare earth as deoxidizer of liquid steel. Moreover, the performances of rare earth in strengthening properties of steel as well as superiorities of purifying liquid steel with rare earth and alkali metal and microalloying of rare earth under low oxygen condition are introduced. The efficient utilizations of rare earth in steel are expected based on summarizing the on-going results.

The baiyuneboite is the largest paragenic ore of rare earth resource reserve in the world. It is the key of effectively utilizing rare earth resources to figure out the inheritance rules of rare earth in steel as well as clearly understand roles and mechanisms of rare earth in steel. In the paper, it is summarized the years of research achievements of authors’ team as well as inheritance of rare earth of baiyuneboite in steel, effects of rare earth on metallurgical quality of steel and microalloying of rare earth in steel. The related fundamental research work can enrich the understanding of roles of rare earth in steel as well as provide theoretical and technical supports for high-quality and efficient utilizations of rare earth resources of baiyuneboite in steel.

The deformation characteristics in rolling process are analyzed through calculating the changes of temperature, strain and external dimensions during the deformation process of H beam with bilinear hardened material model by taking HW300×300 as the typical case. The calculations are with the thinking of all process and calculation method of thermodynamic couple, process temperature is used as deformation temperature of rolled piece as well as the effects of uneven temperature of cross section are taken into full consideration so that the calculation results are more close to actual situations, which provide the reliable basis for process optimization. The calculation results showed that there was necking near the trigonum on waist of H beam due to inhomogeneous deformation, local deformation at flange end would cause precision of flange width to change as well as rolling deformation work would transform into heat energy so that internal temperature of rolled pieces would rise.

The applications of rare earth elements in steel materials play an important role in optimizing their performances. In the paper, it is introduced a type of reinforced wear resistant steel with rare earth TiC particle is prepared by taking rare earth element Ce as main additive as well as systematically discussed the effects of finish cooling temperature on its microstructure and wear resistance. The microstructure analysis indicated that the Ce element could effectively refine the TiC particle with long strip and chain shape in as-cast structure during solidification process as well as the content of retained austenite could be reduced with finish cooling temperature decreased during rolling process. The abrasion test showed that the microalloying TiC particle with rare earth element Ce could effectively prevent abrasion so that the wear resistance of plate could be improved.

In this paper, the fluctuation of impact energy for Q690 steel plate with large thickness of 80 mm are analyzed. The low temperature impact tests of samples taken from different positions of plate thickness are carried out as well as their fracture and microstructure are compared and analyzed with scanning electron microscopy and metallographic microscope. The differences of impact energy at different positions of plate thickness are great, which are 14.9 J in the center, 27.2 J at the quarter part and 95.4 J near the surface. The corresponding microstructures are coarse tempered bainite and a small amount of tempered sorbite structure with orientation of martensite in the center, tempered sorbite and bainite structures with orientation of martensite at the quarter part as well as fine tempered sorbite structure with orientation of martensite near the surface. The analysis results showed that the main cause for fluctuation of impact energy was the differences of microstructure and grain size. The experiment showed that the higher the proportion of bainite in microstructure, the larger the grain size and the lower the corresponding impact energy. Based on the CCT(continuous cooling transformation) curves of Q690 steel, it is analyzed and judged that insufficient cooling during quenching process causes insufficient cooling speed from the quarter part to the center of steel plate due to the larger thickness specification of Q690 steel plate so that the whole martensitic structure could not be obtained after quenching, microstructure in the direction of plate thickness is uneven, especially different proportions of bainite structure appear at the quarter part and in the center of plate thickness, which cause the fluctuation of impact energy. The uniformity of microstructure for Q690 steel plate with large thickness specification is improved so that the impact energy and its stability are improved by optimizing on-site quenching and tempering process.

In this paper, the effects of lanthanum content on inclusions in steel are studied by the induction furnace experiment and thermodynamic calculations. It was concluded that the rare earth oxysulfide was formed firstly, then aluminate, oxide, carbide and sulfide of rare earth lanthanum were formed as well as lanthanum-silicon and lanthanum-aluminum intermetallic compounds and rare earth hydride with smaller reaction trend were formed finally under the thermodynamic condition of molten steel of Q450NQR1 steel for railway carriage. It is obtained that the inclusions of LaAs and LaP could be generated during solidification process through the calculations with Ohnaka segregation model.

The automobile beam steel is mainly used for such structural components as longitudinal beam, lining beam and cross beam on the chassis of heavy truck, so its comprehensive performances are vital to the driving safety and service life of the whole vehicle. The TiN inclusions with large size seriously harm the processability and usability of BT700L steel, while the amount and morphology of inclusions in steel as well as low-temperature impact and corrosion resistance of steel could be improved by rare earth. In the paper, the effects of rare earth Ce on formation of TiN inclusions in BT700L steel are studied based on the industrial tests and thermodynamic calculations. The study results showed that pure TiN inclusions and composite inclusions of Al-O+TiN were mainly formed in the BT700L steel without Ce, while pure TiN inclusions and composite inclusions of Ce-Al-O(-S-Ca)+TiN were mainly formed in the BT700L steel with Ce. The results of thermodynamic calculations showed that precipitation temperature of TiN inclusions could be decreased with the increase of Ce content in BT700L steel so that the precipitation of TiN inclusions was restrained. Such methods as reducing contents of nitrogen and titanium in steel as well as increasing solidification rate could be taken to decrease the sizes of TiN inclusions.

The scientific research innovation management system of Baotou Steel, taking the Management Methods for Scientific Research Projects of Baotou Steel as business framework, covers such five modules as declaration management of scientific research projects, contract management, acceptance management, result management and expense management. As a result, the on line management of the whole process from project approval, accreditation, acceptance and concluding project to results declaration after completing project for scientific research projects of Baotou Steel is realized as well as expense budgets and actual performances of scientific research projects could be controlled according to organization, project and time.