In this paper, it is elaborated the performance characteristics and strengthening mechanism of cold rolled continuous annealed low alloy high strength steel HC500LA for automobile structure as well as the whole production process plan including chemical composition, hot rolling, cold rolling and continuous annealing processes. The production practices and batch trial of automobile manufacturer showed that the HC500LA products of Baotou Steel was with good comprehensive mechanical properties as well as stable and mature production process so that it was with batch supply capacity.

The hot-dip galvanized extra deep drawing steel for back panel of TV with good surface quality, stamping formability, mechanical properties and paint coating property is successfully developed through scientific composition design as well as reasonable smelting, hot rolling, pickling and hot-dip galvanizing process control. Its formability, corrosion resistance, performance stability and higher level of surface quality control could all satisfy users’ requirements.

The galvanized dual phase steel is the high strength steel widely applied in the field of automobile sheet. In order to meet the requirements of lightweight raw material for automobile manufacturer, the galvanized dual phase steel HC300/500DPD+Z is successfully developed through adopting the microalloying composition system of C-Si-Mn-Cr as well as such reasonable process design as hot rolling, pickling, annealing, hot galvanizing and finishing based on the characteristics of 2 030 mm hot galvanizing production line. The production process and using effects of users showed that its mechanical properties were qualified, production process was mature and it was with good formability to meet users’ requirements when applied for automotive structural parts.

The continuous annealing process of phosphorus high strength IF steel 210P1 is tested. The effects of different continuous annealing temperatures on the microstructure and mechanical properties of cold rolled strip 210P1 are investigated with such analysis methods as optical microscope, scanning electron microscope and universal tensile testing machine. The results showed that the grain size gradually increased, non-recrystallization microstructure transformed to recrystallized microstructure and form of microstructure changed from long strip to equiaxed shape with the increase of annealing temperature. The annealing microstructure of steel 210P1 was all ferrite and there was a small quantity of precipitated phase of TiN at grain boundary. The detrimental phase of FeTiP was not discovered so as to demonstrate the continuous annealing process could not cause the phase of FeTiP to be precipitated. The yield strength and tensile strength tended to decrease, elongation, n value and r value tended to increase as well as r value of steel 210P1 increased obviously especially after the annealing of 780 ℃ with the increase of annealing temperature.

In the paper, the process of developing 500 MPa grade low alloy high strength automobile steel is mainly introduced. With the multi-microalloying treatment technology of Nb and Ti combining with controlled rolling and cooling process, the mechanical properties and cold bending property of manufactured pickled automobile structure steel QStE500TM could meet the standard requirements. Its metallographic structure is mainly quasi-polygonal ferrite and pearlite, grain size is uniform and fine, surface quality is good as well as the stable batch production has been realized. As the representative product of pickled automobile steel for Baotou Steel, it is recognized by users.

In this paper, the effects of Nb with different contents on the microstructure and properties of high strength steel are discussed by taking the hot rolled coils with 650 MPa grade structural steel as research object. The data showed that the yield strength of high strength structural steel reduced by about 15 MPa, tensile strength reduced by about 25 MPa and elongation rate increased by about 1 percentage point with reducing content of Nb by 0.010%. It is found that the fine oval precipitates are rich in Nb and square precipitates are rich in Ti in the high strength steel containing niobium and titanium by comparing the microstructures with transmission electron microscope.

In this paper, such aspects as the design background, design process and practical applications of new-type slab turnover machine are introduced. The new-type slab turnover machine in production line of wide and thick plate is designed based on analyzing the defects of traditional slab turnover machine as well as the process requirements and working condition of newly designed slab turnover machine needed to satisfy. It is with such characteristics as high load capacity, stable and reliable performances as well as large range of cover length of turnover slab so that it is suitable for various load lifting devices of slab and with low construction cost.

The application of eccentricity control for high precision gauge control of tandem cold mill is analyzed through comparing the conventional and extended modes in automatic gauge control (AGC) system of tandem cold mill. Moreover, such influencing factors of thinning for product thickness as eccentricity control of rolling mill, thickness variation of incoming materials, variation of tension control for rolling mill as well as precision of thickness gauge and tachymeter are analyzed by comparing the production situations of rolling mill with different thickness control modes. As a result, the improvement scheme that rolling gauge of rolling mill compensates control model is proposed to improve the thickness precision of products.

In the paper, it is elaborated such faults and problems of axial plunger pump with the existing working condition of hydraulic system in Inner Mongolia Baotou Steel Rare Earth Steel Plate Co., Ltd. as overheating of pump body, sealing failure, system pollution, noises and insufficient flow caused by damage of parts, oil pollution, leakage, friction losses and assembly accuracy. Moreover, their inducements and characteristics are analyzed aiming at the generation of faults as well as damage and operation condition of inner components, quality and cleanliness of oil, system leakage and temperature are checked so as to make effective fault diagnosis for hydraulic system as well as ensure the stable operations of axial plunger pump and hydraulic system.

In order to improve the problem of transverse corner crack for peritectic steel, hypo-peritectic steel, medium carbon steel and microalloyed steel containing B, Nb, V and Ti, the chamfering crystallizer successively comes into service of 1^# and 2^# conticasters. As a result, the defect of transverse corner crack is improved obviously, but due to the changes of cooling mode at corner, such defects of billet as longitudinal corner crack, scab and indentation appear easily as well as they could even cause the accident of longitudinal crack and bleed-out. In the paper, it is mainly analyzed such common defects of chamfering ingot blank as longitudinal crack, scab and indentation so that the slab defects are effectively controlled through such measures as adjusting the taper coefficient of copper plate with narrow edge and cooling intensity of secondary cooling water as well as optimizing the assembly accuracy of equipment and modification of key equipment.