In the casting process of rare earth steel, the interaction between molten steel of rare earth steel and mould flux makes the physical and chemical properties of mould flux change so that the metallurgical properties of mould flux are affected and limited. In this paper, the effects of molten steel of rare earth steel on physical and chemical properties and phase composition of mould flux are systematically analyzed. The results show that the rare earth oxide entered slag mainly exists in the form of rare earth silicate. The generated rare earth calc silicate with high melting point is the main reason for the increase of melting temperature and viscosity for mould flux. The longer the action time of molten steel of rare earth steel and mould flux, the more the rare earth oxide is absorbed and dissolved in the slag of mould flux, the more the crystalline mineral is precipitated in the slag and the higher the crystallization rate of slag.

In this paper, it is elaborated the development status and trend of nickel-metal hydride (Ni-MH) battery on railway vehicles as well as introduced the situations of its domestic manufacturers. The advantages and disadvantages of various batteries are compared as well as the technical characteristics of Ni-MH battery are analyzed. In particular, the cylindrical sealed Ni-MH battery is with such advantages as green environmental protection, safe and reliable, maintenance-free and high recovery value so that it is with a certain prospect and significance to popularization and application on railway vehicles.

In the paper, it is introduced the emission requirements of fume particulate matter of gas boiler and excessive emission of all gas boilers in Power Supply General Plant as well as discussed the ways of generating fume particulate matter of gas boiler aiming at its concentration in Power Supply General Plant exceeds the national standard. With the deep analysis of three ways of generating particles, the relation between air quality and excessive emission of fume particulate matter of gas boiler is found. The emission concentration of fume particulate matter of gas boiler is effectively reduced through comparative test of gas boiler with the same boiler type and the methods to reduce it are put forward so that the countermeasures for emission concentration of fume particulate matter of gas boiler to meet current national emission standard and ultra-low emission transformation are put forward.

The hot rolled coil for drill pipe of high strength rotary drilling rig is successfully developed on the 2 250 mm hot continuous rolling production line of Baotou Steel with the component design of low carbon and niobium titanium microalloying as well as controlled rolling and cooling process. Its yield strength is not less than 550 MPa, tensile strength is not less than 650 MPa, percentage elongation after fracture is not less than 25%, longitudinal full-size impact energy is not less than 100 J at -20 ℃ as well as the matching of strength and toughness is good. Moreover, it is with good low temperature impact performance, cold bending performance and welding performance so that it could meet the technical requirements of hot rolled coil for drill pipe of rotary drilling rig for customers as well as its batch production and supply are realized in Baotou Steel.

In this paper, it is elaborated the product characteristics and strengthening mechanism of cold rolled continuous annealing low alloy high strength steel HC420LA for automobile, designed the chemical composition of Nb and Ti as main strengthening elements as well as formulated the complete production process plan including hot rolling, cold rolling and annealing processes. The verification of production practice and batch trial of automobile manufacturers shows that HC420LA is with good comprehensive mechanical properties, mature and stable production process as well as it could be supplied stably.

The rare earth bridge steel is developed by adopting the composition design of peritectic, adding appropriate amount of rare earth alloy as well as applying such advanced processes on the production line of wide and thick plate of Baotou Steel as steelmaking, continuous casting, double stands rolling and cooling. The test results showed that the steel plate was with well-closed formation and excellent performances so as to meet the requirements of national standard. The impact and welding performances of new developed rare earth bridge steel could meet the requirements of using in alpine region through low temperature environment test.

There is cracking on the high strength IF steel HC220Y with phosphorus when wheel cover of automobile is stamped. It is found that there are more MnS inclusions in the steel and a large number of MnS inclusions with long strip shape distributed along rolling direction become the source of cracks by detecting the chemical composition, metallographic structure and inclusions with metallographic microscope as well as analyzing the microstructure and fracture with scanning electron microscope so that the formability of steel plate is reduced and there are cracks on parts of wheel cover of automobile in the stamping process. The problem of cracking is solved by improving the purity of molten steel, reducing content of S in steel as well as strictly controlling amount and form of sulfide inclusions in steel.

In the paper, the effects of Sn on microstructure and texture of hot rolled, cold rolled and annealed sheets with non-oriented silicon steel are studied. After add the element Sn, the deformed grains of microstructure of hot rolled sheet become more prolate, shear band of cold rolled sheet increases significantly, grain size of finished product decreases and texture of γ-fiber of finished product is significantly weakened, which is favorable for increase of texture of λ-fiber. With the addition of Sn, the value of iron loss continues to increase, value of magnetic induction intensity first increases and then decreases and the maximum value is obtained when content of Sn is 0.006%~0.007%.

The cold rolled deep drawing products are affected by all process technologies. The product performances could be optimized effectively by adjusting the process parameters. In this paper, it is introduced the yield ratio of heavy gauge products is reduced, deformability of steel strip is improved so as to meet the operating requirements of users by adopting the integrated scheme of changing cooling mode, increasing annealing temperature and reducing elongation of temper mill aiming at the products with heavy gauge on the basis of stable production of deep drawing steel in a plant of Baotou Steel.

The chemical composition of S450J0 high strength hot rolled steel pile is designed as well as the smelting and rolling processes are formulated based on mechanism of action of vanadium and nitrogen on steel. Moreover, the effects of yield of vanadium alloy and nitrogen as well as finishing temperature in smelting process on vanadium nitrogen steel are analyzed based on the industrial production data. Finally, the European standard high strength S450J0 hot rolled steel pile with heavy gauge as well as ferrite and pearlite is obtained. All the product properties could meet standard requirements.