The ferric charge for tailings after carbonization reaction of steel slag is with magnetic separation, then the feasibility study of returning to sintering for concentrate powder and tail powder of magnetic separation is carried out. Their chemical components are analyzed and the effects of adding them into sintering process on content of P for molten iron of blast furnace are calculated. The effects of concentrate powder of magnetic separation on the sintering components and indexes are analyzed through its sinter pot test. Finally, it is proved that the concentrate powder of magnetic separation can return to sintering process to be used.

In this paper, the production practices on reducing unit process energy consumption of 4 150 m³ blast furnace of Baotou Steel are analyzed and summarized. The unit process energy consumption of molten iron in 2021 reduced by 9.26 kgce/t compared with that in 2020 through strengthening the quality management of furnace burden, recovery of waste heat and power, technology-improving of energy saving and energy-saving management as well as reducing power consumption and making full use of secondary energy sources so that better economic benefits are achieved.

Three-dimensional mathematical model is established with commercial software aiming at the tundish of slab caster to calculate flow field in tundish with different flow control device conditions of tundish as well as analyze the effects of different schemes on flow condition of molten steel and average retention time and the situations of inclusions in steel with adopting the optimization scheme. The results showed that the volume of dead zone for tundish reduced by 10.61% and the time that tracer appeared in tundish extended by 4.31% comparing the optimization scheme with original scheme, which are all beneficial to mixing molten steel in tundish as well as floating and removal of inclusions. Moreover, the level of inclusions in steel adopting optimization scheme could satisfy the requirements of production technology.

In this paper, a kind of high power hydrogen storage alloy powder is studied, its components such as main elements of rare earth and nickel as well as auxiliary elements of Co, Mn, Al and Fe are analyzed by inductively coupled plasma (ICP), its texture is analyzed by X-Ray Diffraction (XRD) test and the platform pressure curve is analyzed by reaction with the hydrogen. Moreover, the high power hydrogen storage electrode alloy is developed by carrying out the tests of particle size and specific surface area for hydrogen storage alloy powder as well as analyzing the electrochemical characteristics of alloy electrode. It is determined to meet the requirements of high power and current for Ni-MH battery by constant power test of battery. The charge-discharge performance with high current of Ni-MH battery is realized by optimizing the preparation technology of cathode.

In the blast furnace bag dust recovered from flue gas in ironmaking process, there are not only the iron, carbon and oxygen contained in solid charge, but also such valuable elements as zinc and lead in the form of oxide as well as potassium and sodium in the form of chloride. In view of the influences and economic value of these elements on ironmaking production, the experiment of “leaching of NH₄Cl → replacement and impurity removal → electrolysis” for blast furnace bag dust is designed and carried out. As a result, the products of potassium ammonium chloride and zinc in line with national standard as well as the optimum conditions of leaching zinc and lead from blast furnace bag dust, precipitation of zinc in leachate, replacement and electrolysis are obtained.

In the paper, the particle size distribution of blended coal is optimized according to the quality indexes of blended coal with different granularity compositions through analyzing properties of blended coal for tamping coking of Baotou Steel with different particle sizes so that standard deviation of granularity composition for blended coal gradually reduces. In addition, the selective comminution of hard coal is carried out through selective precomminution technology so that the quality of blended coal is stabilized. On the premise of ensuring stability of coal cake, 1/3 proportion of coking coal and gas coal is improved so that the consumption of high-quality coking coal and cost of blending coal reduce.

The strength of 440 MPa grade phosphorous high-strength IF steel independently developed by Baotou Steel is improved by adding such alloying elements as Si, Mn and P based on ultra low carbon steel. The control requirements of its composition and production process are strict as well as production is very difficult. In the paper, the influences of chemical elements on stamping performance of 440 MPa grade high-strength IF steel are mainly studied. The microstructure of steel strip, inclusion morphology and precipitation behavior of the second phase particles are analyzed with metalloscope and scanning electron microscope. The mechanisms of action of hot rolling processes such as finishing and coiling temperatures, continuous annealing process of cold rolling on microstructure and mechanical properties are explained. The mechanical performances of tested steel strip are stable and could meet the relative technical requirements through formulating reasonable process route and strict control.

In the production process of 2 250 mm hot continuous rolling band steel, there would be a large number of warp defects at edge of low carbon steel. In order to reduce or avoid the occurrence of warp defect, its causes are analyzed from its morphology, the relation between generation of warp and edging draught of vertical roll of roughing mill, time in furnace and tapping temperature of slab as well as control of Mn/S for composition of slab. Finally, the corresponding countermeasures are formulated so that the occurrence rate of warp defect is reduced.

In the paper, it is introduced the new steel grade 30MnCr25RE is developed for manufacturing L80-1 grade oil casing based on the performance features of hardening and tempering L80-1 grade oil casing manufactured with original steel grade 30MnCr22 by studying the effects of alloy elements in steel. The industrial casual inspection results showed that the minimum yield strength was 570 MPa and maximum yield strength was 625 MPa as well as its fluctuation range was controlled within 55 MPa for L80-1 grade oil casing manufactured with new steel grade 30MnCr25RE. Compared with the original steel grade 30MnCr22, the fluctuation range of yield strength for developed new steel grade is narrower and its performances are more stable. Moreover, the elongation increases by about 4 percentage points comparing with that of L80-1 grade oil casing manufactured with original steel grade 30MnCr22 as well as the impact energy at 0 ℃ could meet the requirements of API spec 5CT technical specification and rigorous technical requirements of users.

The influences of cold rolling reduction ratio and annealing time on the stamping performance of Ti-IF deep drawing steel are studied by means of such equipment as optical microscope, X-ray diffractometer and tensile tester aiming at the phenomenon that the stamping performance of cold rolled cover annealing thick deep drawing steel is unstable. The results showed that the r value and tensile strength tended to increase and change of n value was not obvious with the increase of cold rolled reduction ratio; r value increased, tensile strength decreased and change of n value was not obvious with the extension of annealing time. The process is optimized according to the test results so that density of {111} texture is enhanced and stamping performance of product is obviously improved.