The effects of the scratch defect at rail bottom on fatigue life of rail are studied by MTS100T fatigue testing machine. The results showed that the ability of bearing load for rail was declined and its fatigue life was shortened with the transverse scratch defect at rail bottom. The depth of scratch defect at rail bottom obviously influences the fatigue life of rail. With the scratch defect at rail bottom of 75 mm long, if its depth is 0.3 mm, the fatigue life decreases by 27.2% on average, while if its depth is 0.5 mm, the fatigue life decreases by 31.4% on average.

In this paper, the improvement is from the point of view of deformation process by increasing the number of roll in finished pass to form four-roll finished pass, increasing the constraint in direction of depth of rail and limiting free spread of rail surface so as to improve dimensional accuracy of depth of rail aiming at the existing problems in universal rolling of rail. The numerical calculation is performed using ANSYS/LS-dyna, deformation states in different conditions are analyzed, defects are amended so that the optimal solution is obtained. The better effects are obtained by applying it in production line of rail, fluctuation range of depth within the full length range of rail is reduced and defect of “high zone” caused by local depth fluctuation is solved so that the safety of running for high-speed train is improved.

The Yangliugebu Iron Ore occurs in the amphibolite gneiss of Eastern pentamolecular formation of Seltengshan (rock) group in Neoarchean and the ore body is composed of magnetite quartzite. The amphibolite gneiss and magnetic anomaly are direct indicators for deposit. The iron ore in this area is with stronger magnetic properties, so it can be as an indirect indicator for deposit.

In order to improve the grade of iron concentrate and reduce the contents of other gangue minerals in iron concentrate, the concentration with wash mill is added after finely sieving in Concentration Plant of Baotou Steel. Moreover, such tests as feeding concentration of wash mill, magnetic field intensity, opening of water valve and bottom valve are carried out. Finally, the grade of iron concentrate increases from 56.8% to 67.0%, recovery rate of iron is 93.42% so that the effects of quality improvement and impurity reduction are achieved.

The distribution law of apatite mineral in a tailing of Inner Mongolia is 9.25% and content of P₂O₅ is only 3.73% so that it is low-grade phosphorus mineral. Based on the condition experiment, the open circuit test of primary rougher flotation and secondary concentration is carried out with sodium carbonate as the pH adjusting agent, water glass and HSL as the depressor as well as modified fatty acid TQHY as the collecting agent aiming at the difficult problems of low grade of apatite, many types of gangue mineral containing calcium and similar floatability. Finally, the phosphate concentrate with the grade of P₂O₅ of 33.02% and recovery rate of 78.67% is obtained as well as good separating indexes are obtained.

In the paper, the technical plan of applying high silicon fluxed limonite in sintering of Baotou Steel is proposed through carrying out the sintering experiment of replacing serpentine with high silicon fluxed limonite aiming at the characteristic of low content of SiO₂ in Bayan Obo iron concentrate, which could provide technical support for optimizing the structures of iron charge and flux as well as greatly reducing production costs of sintering production of Baotou Steel. The experiment results showed that the cost of ore proportioning of sintering reduced, but drum strength of sinter decreased by 1.87 percentage points and burn-up increased by 1.06 kg/t by adding 10.2% high silicon fluxed limonite after washing and re-separation into sintering; the cost of ore proportioning of sintering reduced and there were no obvious changes for quality index of sinter by adding 3.4% high silicon fluxed limonite (raw ore), so it was suggested to adopt high silicon fluxed limonite (raw ore) for adjusting the content of SiO₂ in sinter.

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.

As one of the important hot tools in perforated rolling process of seamless steel tube, the quality of guide plate directly affects quality and cost of steel tube. In this paper, the effects of modification of rare earth and heat treatment on carbide shape in high chromium nickel alloy guide plate are studied aiming at the problem of its fragmentation during use. Moreover, the microstructure of net carbide in high chromium nickel guide plate is fragmentated and broken, matrix structure is refined and carbide uniformly distributes by selecting reasonable process so that the purpose of improving service life of guide plate is achieved.

In the paper, the continuous cooling transformation (CCT) curve of test steel is determined with FORMASTOR-F full automatic phase transformation instrument by taking 38CrMoAl steel as the research object. The results showed that the microstructure at room temperature was proeutectoid ferrite+pearlite when cooling rate was 0.2~ 0.5 ℃/s; the microstructure at room temperature was ferrite+pearlite+bainite and there was a small amount of bainite when cooling rate was 0.5~1 ℃/s; the bainite was formed at the temperature near Bs in the uppermost part of transition zone for bainite and the microstructure at room temperature was upper bainite when cooling rate was 1 ℃/s; the martensite increased continuously and bainite decreased gradually as well as the microstructure at room temperature was mixed microstructure of bainite+martensite when cooling rate was 2~5 ℃/s; the microstructure at room temperature was just martensite when cooling rate was not less than 5 ℃/s, which provide the reference basis for formulating heat treatment process.

Such problems as abnormal wear of such components as lining plate, uneven product particle size as well as short service life and high manufacturing cost of such components as lining plate, spider cap and head nut caused by uneven burden distribution of distributing device are found during the process of using Sandvik CH-870 crusher in Baoshan Mining Co. so that the frequency of maintenance and operating cost for crusher are high in the early stage of operation. In this paper, the working principle of Sandvik CH-870 crusher is introduced as well as its components such as distributing device, spider cap and head nut are improved combining with the actual situations on site. The operation of equipment is stable, processing capacity of crusher is obviously improved and operating maintenance cost is reduced with the improvement, which provides the references for other enterprises to introduce CH-870 crusher.

As the important energy medium, gas is widely used in each working procedure of metallurgical enterprises, but the inaccurate measurement of mixed gas flow always troubles accurate measurement of enterprise energy. In the paper, it is introduced the composition and general situations of mixed technology for gas of Baotou Steel, elaborated the measurement principle of throttling differential pressure flow meter, analyzed the causes of errors with differential pressure flow meter in the detecting system of mixed gas flow as well as proposed the method for correcting measurement of mixed gas flow under different working and equipment conditions so that the problem of inaccurate measurement of mixed gas is solved.

In this paper, the design and implementation processes of intelligent quality inspection system for scrap steel are mainly discussed. The system adopts such advanced intelligent technologies as artificial intelligence (AI), big data analysis and video capture to automatically analyze and grade the iron and steel scrap in storage so that such problems as inaccurate identification and unwarrantable objectivity caused by artificial quality inspection are solved. The system can be interconnected with the measurement system, settlement system and warehouse system to automatically generate settlement reports so that work efficiency can be greatly improved as well as safe, accurate and high-efficiency operation of scrap steel inspection is promoted.

With the growth in the people’s living standard, the demand of resources is more and more, which leads to continuous exploitation of a large number of mineral resources in our country so that there are many ecological problems. In this paper, the ecological impacts of strip mining in desert steppe are analyzed from such aspects as plant and animal resources, land resources as well as landscape through field investigation in project area by taking the strip mining project in Dongkekeyiligeng mining area of Darhan Muminggan Liahheqi in Inner Mongolia as an example. Moreover, the suggestions on ecological conservation measures of strip mining are put forward based on the theory of restoration ecology.