In the paper, it is mainly introduced the application of solidification terminal electromagnetic stirring technology in round billet caster at Baotou Steel. The results show that when the billet section is Φ390 mm and the steel type is medium carbon steel, the optimal F-EMS parameter is 450 A/8 Hz. The central carbon segregation index of the billet is reduced through the optimized F-EMS parameter, and the equiaxial crystal ratio of the billet is increased, by which the internal quality of continuous casting billet is improved.

The reasons for the frequent damage of tuyere in No.3 blast furnace of Baotou Steel are analyzed, and measures such as reducing the alkali load, maintaining the upper limit of physical temperature, furnace temperature controlling mainly in physical temperature, lowering the coal ratio, and strengthening the foundation work are adopted to control the frequent damage of tuyere.

Through the optimization design of the system, the operation efficiency of the 1 000 m³ blast furnace feeding system in the old area is improved, which makes the technology distribution of the dust removal pipeline more scientific, the air volume reasonably distributed, and the dust removal capacity matched with the production process. Reduce the post dust concentration to the exposure limit specified by the national standard.

The paper briefly explains the working principle of Baotou Steel distributor and its application in No.7 blast furnace top distributor of Baotou Steel. The reason for the short life of distributor is analyzed, and the performance characteristics before and after improvement of distributor are studied. The replacement process of the new distributor (Qin Ye distributor) in No.7 blast furnace is introduced. After the replacement, the distributor reaches the requirements of angle burden distribution in blast furnace, which plays a positive role in stable and smooth production of blast furnace.

The paper mainly introduces that the 80 t converter completes the transformation of quick-change bottom blowing system and realizes the nearby sub-control function for the gas supply pipeline; protect the gas supply line connection at the furnace bottom and the four air-permeable core bricks; according to the different production conditions, optimize the bottom blowing air supply intensity; achieves blowing airflow smooth and strength stable throughout the furnace service, and guarantees the bottom metallurgical effect during the furnace service.

In the paper, it is briefly introduced the process flow of converter gas dry purification and recovery system, combined with actual production data, analyzed the factors influencing the gas recovery from various aspects such as process control, equipment operation, and organizational management, proposing the practical and feasible method to improve the recovery calorific value of converter gas, and the recovery and utilization of converter gas produced in the steelmaking process, which will not only bring better economic benefits to enterprises, but also effectively ease environmental pressure.

In the paper, it is expounded the process flow of steelmaking refining furnace, and introduced the technical process parameters and characteristics of dry VD furnace and steam VD furnace in Baotou Steel, and the energy-consuming equipment of two vacuum degassing systems for steam VD furnace and dry VD furnace in Steel-melting Plant are monitored in real time. Through analysis and calculation of test technical data, economic and technical indicators such as per ton steel energy dissipation ratio, fractional energy saving and per ton steel cost ratio are obtained.

The article mainly introduces the various strip break accidents that occurred in 1 780 mm cold rolling mill of Baotou Steel in recent years. The reasons for the mill strip break accidents are found from the hot-rolled materials, laser welding machine, tension leveller, trimming shear, rolling plans and other aspects, based on that, effective measures have been made in optimizing hot rolling process, laser welding machine parameters, tension leveller elongation, rolling plan lap and cold rolling equipment maintenance inspection and so on, through which the unit strip break has decreased significantly, and the operation rate has increased significantly, achieving good economic benefits.

The paper analyzes the water quality and existing problems of circulating water system in a Steel-melting Plant. Through experiments, the influence of circulating water on corrosion and scaling of carbon steel is studied, and the feasibility of increasing the concentration multiple of circulating water system is analyzed. The optimized operation parameters of the circulating water system are put forward through experimental study, and the feasible measures for water-saving and emission reduction are put forward based on the actual situation on site in Steel-melting Plant.

Through the analysis of the decomposition reaction process, the factors affecting the crude phenol moisture are found. The high pH value of solution after decomposition, the unstable stirring speed of compressed air, the short standing time and the water leakage of the pipeline have great influence on the high moisture content of crude phenol. By adjusting the pH value of solution 5~7, slowly adjusting the wind speed, prolonging the standing time and reforming the pipeline, the moisture content of crude phenol is significantly reduced from more than 16% to less than 14%, good results having been achieved.

The hot rolled drilling pipe STM-R780 is normalized. Experiments are carried out with different normalizing temperatures and holding times. Technical parameters such as yield strength, tensile strength, elongation, and metallographic structure of steel pipe are measured by relevant experimental equipment. The proper normalizing heat treatment system for strength and toughness is found out by analyzing the data.

In the paper, the systematic study is carried out on the proportion of Baotou Steel self produced concentrate in pelletizing through optimizing ore proportioning method. The results show that with the addition of bentonite, in the condition of without increasing the other flux, the highest proportion of self produced concentrate in pelletizing can reach 35%; while in the condition of increasing magnesian flux, the proportion of self produced concentrate can reach 40%, and the finished pellets index can meet the requirements of the pellet index for 4 150 m³ blast furnace in Baotou Steel.

In the paper, it is introduced the research situation on standard residual stress of heat treatment rail in Baotou Steel, and analyzed the heat treatment rail of Baotou Steel by means of patch method, incision method and X-ray diffraction, and analyzed the residual stress date of on-line heat treatment rail in Baotou Steel by being compared with hot rolled rail. The patch method test results show that the residual stress of rail heads for heat treatment rail produced by Baotou Steel is larger than that of hot rolled rail; the incision method test results show that the overall residual tensile stress of rail is larger than that of hot rolled rail; the X-ray diffraction method shows that the residual stress distribution on rail surface is uneven.

Through the end of converter, LF refining, VD vacuum treatment and full protection continuous casting and heating system, rolling process, non-metallic inclusion, strict control of carbon segregation and other aspects, and the analysis of metallographic phase for finished bearing steel, crack defect, low power steelmaking composition, the bearing steel is successfully researched and developed, meeting the standard requirements of GB/T18254-2016 and entering the market.

Strictly controlling the content of C, Mn, P, S and gas elements in steel is the key factor to improve the purity of molten steel, reduce the segregation of casting blank, and increase the resistance to H₂ S corrosion. The proper addition of alloys and the rational formulation of smelting, continuous casting and hot rolling process system is an important link to ensure that the product meets the standard requirements. The chemical composition and process design of X52MS hot rolled coils developed by Rare Earth Steel Plate Plant of Baotou Steel are reasonable, and the steel is pure, uniform in structure and has excellent comprehensive mechanical properties, in particular, it has resistance to hydrogen induced crack and stress corrosion resistance, product quality having reached the international advanced level.

Relying on 2 250 mm hot continuous rolling production line of Rare Earth Steel Plate Plant, adopting low－cost design of medium carbon and a small amount of Cu and Ti, through pretreatment of hot metal, converter smelting, LF refining, continuous casting, slab, heating, rough rolling, finish rolling, laminar cooling, coiling and other processes have successfully developed hot rolled steel strip for 520 MPa grade concrete mixing tank. The trial-produced results show that steel strip has good mechanical properties, stable and uniform steel strip performance, excellent formability, and good wear resistance. The steel strip contains less inclusions, and the steel is pure. The main components are ferrite and pearlite, and the grain size is small and uniform, and the grain size reaches 12 grades, the performance fully meeting the requirements for mixing tank use. It is successfully applied and sold in batches, praised by users, having broad application prospects.

In the paper, it is mainly discussed the use of special-shaped blank to produce Q345NQR2 corrosion resistant H beam. Through the chemical composition design and the process control of production processes in smelting, continuous casting, heating and rolling of Q345NQR2 corrosion resistant H beam. Both the microstructure, mechanical properties and corrosion resistance of Q345NQR2 corrosion resistant H beam are met the technical requirements for longitudinal beam corrosion resistance steel use as the railway vehicle underframe.

Through laboratory tests, the influence and analysis of Cr, Mo and V alloying on hardenability of bucket teeth steel are studied. The test results show that Cr, Mo and V alloying for improving the hardenability of steel, especially after J19 mm, the hardness of end hardenability obviously slows down.

Metallographic microscope and scanning electron microscope are used to analyze the SAPH440 stamping cracked steel plate. The analysis results show that the existence of segregated band of mixed crystal and pearlite in the steel plate and the combined action of precipitation of cementite at the grain boundary cause the crack of steel plate during stamping.

The effect of different coiling temperature on microstructure and mechanical properties of high strength engineering mechanical steel BT600MC is studied. In the smelting and rolling laboratory, three rolling billets with the same chemical composition are rolled by controlled rolling and cooling process, and the final coiling temperature is controlled at 500 ℃, 550 ℃, and 600 ℃ respectively, and after rolling, the steel plates are placed in the simulated coiling furnace for 2 h, and the temperature is cooled naturally. The experimental results show that when the coiling temperature is 600 ℃, the ferrite grain is more fine and uniform, and the comprehensive mechanical properties of experimental steels are better.

With the rapid development of motor industry in China, demand for cold rolled non-oriented electrical steel has increased year by year, according to the current situation, the test results of magnetic properties for cold rolled non-oriented electrical steel are analyzed, including sample preparation equipment, environmental temperature, sample size, sample weight, sample density and test equipment and so on. The results show that with the increase of shear times, mass and density, the iron loss increases, and the magnetic induction decreases; with the increase of ambient temperature, the iron loss and magnetic induction decrease. The analysis of factors affecting the test results of magnetic properties for cold rolled non-oriented electrical steel has great significance to improve the accuracy of test results.

In order to produce low chlorine root rare earth oxide, through the treatment of organic solvent entrainment in feed liquid and precipitant, the improvement of rare earth carbonate washing method and process method after rare earth carbonate, the content of chlorine root and other impurities in rare earth products can be effectively controlled, and the low chlorine root rare earth oxide products can be obtained.

In the paper, it is mainly described the structure and characteristics of the main drive electric control system of roughing mill in large H-beam production line for Rail and Beam Plant of Baotou Steel. The system adopts SIMADYN D full digital vector control system of Siemens to control; through Profibus_DP network to achieve signal acquisition and data exchange with one level automation system, the system can adapt to the demand of rolling conditions being frequent reversible, heavy impact load and high overload capacity.

In the paper, it is introduced the transformation of control system for walking beam furnace in Seamless Plant. The old Siemens S5 system has outdated equipment, high failure rate, complicated communication, poor programmed readability and is difficult to maintain. After the transformation, Siemens S7-300 controller is used, which has good versatility and high control precision. The programming adopts STEP7 + WINCC mode, and the program adopts modular programming mode with clear structure, strong expansibility and is easy to maintain.

In view of the problems existing in the operation of 110 kV rod suspension composite insulators used in electric transmission lines, the structure of composite insulators is designed and optimized. Under the premise of meeting the requirements of specification and technical parameters, through changing the structure and size of composite insulator umbrella skirt, the hydrophobicity performance and anti-icing performance of the composite insulator are improved, and the anti-fouling and anti-pollution performance are further improved, which ensures the reliable and stable operation of electric transmission lines.

In the paper, it is designed the water-level detecting device for cable trench. Using the STM32F103Rx microprocessor and GPRS communication module, the automatic monitoring device for cable trench water inlet point is developed to monitor whether water entering the cable trench. Based on VS2010, the cable trench detecting system in the plant is developed, receiving the return path signal of detecting device, and when a cable trench occurs water entering, the system will provide alarm, notifying the maintenance personnel to deal with it in time, greatly reducing the occurrence of related accidents.