In the paper, the production practices on increasing production and reducing fuel ratio for 7^# blast furnace of Baotou Steel are summarized. In September 2022, the average daily output reached 9 370.7 t/d, utilization coefficient of effective volume for blast furnace was 2.258 t/m³·d and fuel ratio was reduced to 548 kg/t through taking a series of effective measures such as strengthening the management of crude fuel, increasing wind-warm syndrome, furnace top pressure, oxygen enrichment rate, batch weight of ore and coke ratio of ore into furnace as well as optimizing the charging system, reducing the amount of central coke and improving gas utilization rate.

The hot-rolled coil with X52MS pipeline steel for acid service by industrial production is chosen as the research object as well as its material performances are analyzed from microstructure and chemical components. Its resistance to hydrogen induced cracking (HIC) behavior in H₂S solution is mainly studied, the effects of microstructure and microregion components on the resistance to HIC are investigated by HIC test as well as the main causes for crack generation are analyzed so that its regularities are found out. It is summarized that banded structure is the main cause for failure of resistance to HIC for this material, carbon segregation and central aggregation of inclusion of carbohydrates and nitrogenous compounds would worsen the effects of banded structure on the HIC performance; the thought of low carbon component design is the premise of designing pipeline steel for acid service as well as reasonable control of nitrogen content is also one of the considerations in production of pipeline steel for acid service.

The industry is the pillar industry of national economy. In the process of industrial production, its virtual simulation is carried out with the computer simulation technology, the running conditions of production line could be simulated by the simulation technology so that the rhythm of production and technological process are optimized as well as production efficiency and capacity are improved; the layout of production line, process arrangement and equipment configuration are optimized to improve production efficiency, reduce production costs and waste of resources. In the paper, the solutions for intelligent production line of rare earth oxides are designed with the computer virtual simulation technology by taking the intelligent manufacturing project for production line of rare earth products as example. It plays role in optimizing the technological process of intelligent manufacturing and layout of production line of rare earth oxides products. Moreover, the real scenarios of industrial production and virtual reality simulation are deeply integrated with the simulation technology so that customers could truly feel and understand the intelligent manufacturing process of production line of rare earth oxides.

In order to expand the coal resources for coal injection of Baotou Steel and reduce the fuel cost of blast furnace injection, the laboratory study on applying hydrogenated semi-coke with destructive distillation in blast furnace injection is carried out by Baotou Steel. The results showed that the hydrogenated semi-coke with destructive distillation was high quality fuel of blast furnace injection with such characteristics as low moisture, volatiles and sulfur content as well as high fixed carbon, however, its bulk density was much smaller than that of mixed pulverized coal as well as its combustion rate was better than that of existing mixed pulverized coal and without explosiveness so that its combustion and safety performances could meet the safety requirements of blast furnace injection.

The effects of structure of retaining wall and dam on the flow condition of liquid steel in tundish are studied based on the physical model with geometric similarity ratio of 1∶4 established according to the similarity principle by taking the six-strand continuous casting tundish of bloom of Baotou Steel as the object of study. The results showed that the average retention time of liquid steel was increased by 5.51% and proportion of dead band was reduced by 20.73% by comparing the structures with and without retaining wall and dam. The flow condition of liquid steel in tundish could be effectively controlled, peak time and average retention time of each strand for tundish are increased as well as volume of dead band for the whole tundish is reduced so as to be beneficial to fully mixing liquid steel in tundish as well as aggregation and floating of inclusions.

The iron ore samples are decomposed with the hydrochloric acid and hydrofluoric acid. After the perchloric acid smokes and silicon is eliminated, it is then extracted by butyl acetate solution of 1-phenyl-3-methyl-4- benzophthalide-5(PMBP). The interference elements of thorium are eliminated by the reextraction with hydrochloric acid, arsenazo III is as color developing agent and forms purple-red chelate with thorium ion as well as the thorium content in iron ore is determined with spectrophotometer. In the paper, the selection of acidity for extraction and reextraction, effects of such factors as acidity of chromogenic reaction, amount of color developing agent and color developing time on determination are discussed as well as experimental parameters are optimized. At the maximum absorption wavelength of 660 nm, the linearity range of thorium is determined to be 0~1.0 μg/mL, correlation coefficient is not less than 0.999 and detection limit is 0.000 44 μg/mL. This method is easy and simple to operate, molar absorption coefficient of the complex formed by arsenazo III and thorium is up to 0.8×10⁵ L/(mol·cm), which is with higher sensitivity. The adding standard recovery of thorium in the analysis results of samples is 96.8%~105.8%, so the method is with good precision and accuracy.

In this paper, the mechanical properties and metallographic structure of the joint with different welding technologies are compared and analyzed with the theoretical calculations of crack sensitivity index and preheating temperature as well as the methods of inclined Y-groove welding crack sensitivity test combining with operative weldability test of steel plate. Moreover, the JM-100 welding wire and 80%Ar+20%CO₂ argon-rich gas are determined to be adopted for welding the Q550D steel plate with thickness of 20 mm. The crack sensitivity index is 0.28, minimum preheating temperature is 13 ℃ and preheating treatment is not needed during welding. The welding heat input is controlled at 9.0~24.8 kJ/cm, temperature between weld passes is controlled below 200 ℃, mechanical properties of joint reach the best and there are no coarse and abnormal structures in weld seam and heat affected zone.

In the field of space launch, the filling system of liquid oxygen relates to whether launch mission is successful or not, so the measurement of flow velocity for liquid oxygen is crucial. The vortex flow meter is often used as its measuring instrument due to its advantages such as stable performances and wide ranges. It is found that the vortex street coefficients of vortex flow meter show different characteristics at low and high flow velocities through experimental simulation so that the precision of vortex flow meter is poor at low flow velocities. In order to explore the change characteristics of vortex street coefficient for vortex flow meter at low and high flow velocities, the simulation experiment of vortex street flow field with flow velocity of 1.0~10.5 m/s at inlet is carried out as well as the relational graph of vortex street frequency and inlet velocity is obtained. Moreover, the fitting curve of vortex street frequency and vortex street coefficient is obtained through fitting curve. Finally, it is found that the fluid flow velocity obtained by curve fitting is more accurate through calculating flow velocity with the obtained vortex street coefficient curve and average coefficient.

In this paper, the optimization plan of chemical composition, hot rolling and annealing processes is formulated through analyzing the influences of stress concentration, inclusions, chemical composition, mechanical properties and metallographic structure on fatigue strength with the metallographic microscope and field emission scanning electron microscope. The results showed that the tensile strength of material could be improved by 11~45 MPa by increasing the contents of carbon and manganese in chemical composition, reducing the content of harmful element sulfur as well as matching hot rolling and annealing processes so that the pearlite in metallographic structure was granular and with dispersed distribution. After made into the guide rail, its push-pull effort, service life and functions are tested as well as it is determined to be qualified according to the standard requirements.

In order to reduce the content of gangue minerals in iron concentrate, improve the grade of iron concentrate as well as reduce the consumptions of reagents and steam in the flotation process flow of iron, the magnetic separation with elutriation is added in the original process of Baoshan Mining Co. and the operation of a set of flotation system is reduced. The process of elutriation-flotation shows the good function of improving grade of iron as well as reducing contents of silicon, potassium and sodium. The grade of iron of iron concentrate reaches 67.07%, content of SiO₂ is 1.98%, content of K₂O and Na₂O is 0.172%, total operating productivity is 79.60% and recovery rate is 93.27%.