In this paper, it is introduced the current situations of such rail standards as AREMA Railway Engineering Maintenance Manual(2020), European Standard EN 13674-1:2011+A1:2017 and China Railway Industry Standard TB/T 2344.1—2020 as well as mainly compared and analyzed the differences of cross section, compositions, properties and test methods for rails satisfied the above three standards. The analysis results showed that the differences of technical requirements for rails satisfied the above three standards were greater due to the level and style of domestic and foreign standards were different. The export level of domestic rails is fully known by comparing these differences, which creates conditions for exporting domestic rails to the international market.

The cracked part is analyzed with metallographic microscope and scanning electron microscope aiming at the peeling and cracking of hot rolled high strength beam steel plate during the process of bending. The results showed that many continuous punctiform or banded inclusions containing O, Al and Ti elements were distributed close to the surface layer at cracking; metallographic microstructure of decarburized layer on surface layer of steel plate was coarse equiaxed ferrite. The analysis suggests that hard inclusions, TiO₂ and Al₂O₃ destroy the continuity of product matrix and plasticity of surface layer is reduced by microstructures of oxidation and decarbonization, the matrix with inclusions fractures firstly in bending process, which makes the deformation of upper surface layer increase and it is out of tolerance range so that peeling and cracking are formed. The problem of lamellar cracking during bending for steel plate is solved by adopting the technology of pre-blowing argon in tundish to prevent oxide inclusion caused by secondary oxidation of molten steel at the initial stage of pouring.

The optimized coal blending system for coal injection is independently developed based on considering the physicochemical characteristics, safety performance and processing property of coal injection aiming at the problems in process of optimizing coal blending for coal injection of blast furnace. The coal blending scheme with cost optimization satisfied the constraint conditions of production demands is calculated by adopting the hybrid programming technology of VB+EXCELVBA, invoking such algorithms as plan solution and multiple linear regression as well as taking ACCESS as background database. The production applications show that the system model plays an important role in reducing costs and stabilizing quality for coal injection of blast furnace.

In this paper, the microstructure and macrotexture of Hi-B steel at various stages of production are analyzed with such detection means as Zeiss microscope and X-ray diffractometer. The results showed that the microstructure of Hi-B steel was ferrite at all production stages. The microstructure is completely recrystallized after decarbonizing and nitriding annealing and average grain size is 28.92 μm as well as secondary recrystallization is completed after high temperature annealing and average grain size of finished product is about 2 cm. The texture types in sub-surface of hot rolled plate are mainly three types of typical shear textures. The texture of cold rolled plate is mainly composed of α line texture and rotating cube texture {001}<110>, the texture after decarburizing annealing is mainly α^* texture and γ line texture {111}<112> as well as the macrotexture after high temperature annealing is mainly Goss texture. The texture of Hi-B steel after stretching, leveling and annealing is single Goss texture with accurate orientation as well as its strength reaches peak.

With the increase of yield of iron concentrate and rare earth ore concentrate of Baoshan Mining Co., it is necessary to increase the processing capacity of ball mill to increase yield, while the most effective measure is to increase the fine fraction content of feedstock of ball mill so that more crushing and less grinding is achieved. In the paper, it is introduced the existing crushing and screening system of Baoshan Mining Co. is optimized through improving the distributing device of crusher, adjusting the eccentric distance of intermediate crusher as well as improving the dimension of screen hole for screen cloth of vibrating screen. As a result, the machine-hour yield of fine crusher is increased by 40.71 t/h and operation rate of crusher is reduced sharply; service time of liner plate for intermediate crusher is extended by 15 days and service time of liner plate for fine crusher is extended by 30 days; screening efficiency of vibrating screen is increased from 81.43% to 84.70% and content of feedstock with size fraction of -12 mm under it is increased from 81.43% to 94.12%; processing capacity of ball mill is increased to 380 t/h, which creates conditions for increasing the yield of iron concentrate and rare earth ore concentrate.

The blast furnace hearth is the key part that restricts blast furnace campaign to over 15 years and the key factor determining blast furnace campaign. The direct causes for temperature rise on side wall of hearth are determined to be aggravated circulation of molten iron and severe erosion of carbon brick through studying erosion mechanism of hearth aiming at the rise of side wall temperature of 5^# blast furnace hearth. The temperature at iron notch of elevation of 8.663 m for side wall of hearth is decreased and basically stabilized at 350~450 ℃ before blowing out, which is within controllable range through taking such preventing measures as setting the early warning standards, strengthening daily management, optimizing standards of depth of iron notch and strengthening maintenance as well as adjusting production and operation parameters based on three-grade early warning.

The effects of riser brick for casting ingot mould used in the smelting equipment of laboratory, vacuum induction furnace on quality of steel ingot are greater. The molten steel in vacuum melting furnace is poured into ingot mould through riser brick and steel ingot is formed after cooling. The flow velocity and angle of the molten steel flowing through riser brick, inclusions in molten steel and inner wall of ingot mould all affect quality of steel ingot. In the paper, the optimization design for structure of riser brick is introduced, which is to add a diversion platform. On the one hand, the scouring force of molten steel to inner wall of ingot mould is reduced so that the service life of ingot mould and surface quality of steel ingot are improved; on the other hand, the retention time of molten steel in riser brick is increased so that the inclusions in molten steel float to be removed and internal quality of steel ingot is improved. The practices prove that the design of riser brick with optimization and transformation is reasonable as well as application effects are good.

The changes of microstructure for air quench steel slag are studied by observing the changes of various phases in air quench steel slag with time as well as calculating the numbers and area of particles for various phases with the softwares of Photoshop and Image J. The results showed that the phase types of air quench steel slag were not changed with time and diffraction peak intensity was slightly decreased. The number of particles for dicalcium silicate phase in slag is decreased significantly with time and total area of the phase is changed a little. Within 20 days,the average particle size is increased from 4.96 μm to 6.06 μm, while there are no significant changes for other phases. It can be seen that the increase of particle size for dicalcium silicate is due to its own recombination, not the change of other phases. The equation of phase change for dicalcium silicate in air quench steel slag is 1-(1-α)^1/3=0.039 T.

In this paper, the production technology process and relative process parameters of new product, 27SiMn spring steel plate are introduced. The microstructure needed by product is obtained through reasonably setting cooling parameters after rolling, with which the mechanical properties of product are ensured. The using status of users shows that the performances of 27SiMn spring steel plate are good by making full use of existing equipment of Baotou Steel, adopting reasonable process parameters under the condition that both of raw materials and liquid iron meet the requirements. Its tensile strength is not less than 800 MPa and elongation is not less than 19%. Moreover, the effects of atmosphere in heating furnace on decarburized layer on the surface of medium carbon steel with silicon are important, decarburized layer on the surface of 27SiMn spring steel plate is just 24% of the requirements in the national standard GB/T 1222—2016 by reducing atmosphere and micro-positive pressure operations in heating furnace.

As an efficient energy conversion system, the combined cycle power plant (CCPP) is widely used in such industrial fields as iron and steel. As the core component of CCPP, stable operation of waste heat boiler directly affects efficiency and safety of the entire unit. In the paper, the in-depth study aiming at frequent leak problem at the upper part of high pressure evaporator of supporting waste heat boiler facing flue gas in gas turbine unit of a steel plant is carried out as well as the leakage causes are analyzed to be that the deposit sediment in its lower header causes water flow rate in evaporator tube to be decreased so that impingement corrosion of steam water mixture is generated. Meanwhile, the phenomenon of “flue gas corridor” in local area of furnace exacerbates the corrosion process. For these problems, such measures as replacing leaking pipe section, reforming periodic discharge pipe system of lower header to improve efficiency of pollution discharge, repairing and perfecting gas baffle to reduce formation of “flue gas corridor”, optimizing periodic pollution discharge operations as well as formulating periodic plans of inspection and maintenance are taken to effectively solve the leak problem for high pressure evaporator so that the stability and safety of equipment are improved.