The 5th generation American Morgan technology was introduced in the early 1990s for a production line of high speed wire rod and its design capacity was 0.38 million tons. With the constant improvement of production technology and efficiency for the deep processing industry of wire rod, the requirements of dimensional accuracy, surface quality and mechanical properties for wire products in the market are higher. In order to satisfy the market changes and improve product competitiveness, the size reducing mill is added in the production line of high speed wire rod. In the paper, it is introduced the construction transformations of such types of equipment as mechanical, electrical and power as well as the roll gaps of finishing rolling unit and size reducing mill are redesigned. Moreover, the R values of each stand are given as well as different accident types and solutions after the mill put into production are summarized.

The mineral species that have been found in Bayan Obo ore deposit are sorted and recorded based on the list of mineral species in Bayan Obo mining area in Mining and Metallurgical Technology of Baiyuneboite as well as the research achievements of minerals of Bayan Obo are collected combining with such documents as Mineralogy of Bayan Obo. The results showed that there were 172 types of minerals in the list of mineral species in Mining and Metallurgical Technology of Baiyuneboite after correct obvious errors, the minerals reached 191 types by supplementing the minerals that were not recorded in Mineralogy of Bayan Obo; a total of 209 types of minerals have been found in Bayan Obo ore deposit so far, together with the newly found minerals and new minerals.

The stock of medium-lean oxidized ore in Bayan Obo is huge as well as its degree of oxidation and impurity content are high. Among them, iron and rare earth are the main recovered components. The grade of iron is 28.74%, content of FeO is 1.99% and grade of rare earth is 5.45%. The iron in the ore mainly exists in forms of hematite and limonite and magnetic iron as well as the distribution ratios are 48.54% and 43.84% respectively. The qualified iron concentrate with grade of iron concentrate of 66.07% and gross recovery of iron of 87.47% is obtained by studying the ore properties of medium-lean oxidized ore in Bayan Obo as well as exploring and recycling its iron resource with the process of “preconcentration-hydrogen-based mineral phase transformation-stage grinding-stage magnetic separation”. This method is beneficial to the full utilization of iron resources and improving the utilization rate of mine resources.

It is considered that there is no direct relation among the bubble coke rate for large capacity coke oven and the strength, ash content as well as scurf resistance M₁₀ of coke after reaction while there is certain correlation between it and coking time through their data analysis. As a result, it could not be as the evaluation index for coke quality.

Four new types of coal are increased through developing independently and introducing the new types of coal in Shanxi and Inner Mongolia as well as utilizing the SXLLSJM、SXJM and HDSJM, part of which is instead of such types of coal with tension supply as ZYDM and LLGHM. As a result, the scope of coal used for rammed-coal coking is expanded, tension trend of using coal is relieved, the existing coal blending structure of rammed-coal coking is optimized and coke quality is improved. The ash content of coke is reduced and the hot strength of coke is increased, which provide the strong fuel support for the stable and trouble-free operation of blast furnaces of Baotou Steel.

The process of blowing out by lowering the charge level is smooth. Moreover, the whole process without detonation, rapid blowing out with safety and environmental protection are realized through activating the furnace hearth, calculating and analyzing loading of light load materials, adopting high blowing rate in early stage to make coke burnt as quickly as possible, improving atomization device to reduce the amount of water injected into furnace top, refining tapping in stokehole, reasonably controlling the relationship between air pressure and blowing rate, shortening the time of gas release, efficiently organizing, safely placing residual iron and coordinating various systems.

In this paper, the sintering productions with such SiO₂ contents in sinter as 4.75%, 4.85%, 4.95%, 5.15% and 5.30% are carried out based on the effects of different SiO₂ contents on sinter with 500 m² sintering machine. The results showed that the drum strength of sinter was increased with gradual increase of SiO₂ content in sinter when SiO₂ content in sinter was less than 5.15%; the drum strength of sinter was optimum when SiO₂ content in sinter was about 5.15%, which was increased by 3% compared with that of 4.75% and average particle size was increased by 1.77 mm; the drum strength changed slightly with continuous increase of SiO₂ content when SiO₂ content in sinter was increased from 5.15% to above 5.30%. The analysis on the microstructure of sinter with different SiO₂ contents showed that the prismatic tabular calcium ferrite was increased with the increase of SiO₂ content and the dicalcium silicate of partial region was with large area enrichment. With the high proportion of self-produced concentrate of Baotou Steel, the SiO₂ content is controlled at about 5.15%, drum strength of sinter can reach above 79.5% and average particle size can be improved above 19 mm.

In the paper, the restraining factors affecting recycling fly ash of sintering machine head and blast furnace bag are discussed as well as the key technologies of extracting such valuable elements as Zn, K and Na from the fly ash are studied by analyzing its characteristics and disposal status. The technical plans for comprehensive utilization of fly ash of sintering machine head with high alkali metal content as well as fly ash of blast furnace bag with high zinc and alkali metal contents are proposed combining with such cases as salt extraction technology by washing for fly ash with high alkali metal content, zinc extraction technology with pyrogenic and wet processes for fly ash with high zinc content and reduction technology of electric arc furnace for iron-bearing dust as well as evaluating their merits and demerits. After implement the plans, the disposed fly ash could be recycled for sintering as well as products of Zn, K and Na could be sold externally so that the economic benefits are considerable and the problems of land occupation and environmental pollutions could be solved.

In the paper, the recrystallization annealing process is studied by taking Fe-Mn-Al-C high manganese austenitic steel as object of study. The thermal simulation tests with series of temperatures, hardness test and metallographic analysis are carried out to the test steel. The study results showed that the recrystallization temperature was 750 ℃ when annealing holding time was 120 s and recrystallization temperature was increased to 800 ℃ when annealing holding time was shortened to 60 s. The grains remain uniform and fine as well as hardness value of test steel is with a little change when the holding time is 120 s at 750~900 ℃.

In the paper, the production technology process and process control system of wide and thick plate mill in Baotou Steel are briefly introduced. The wide and thick plate mill is the important component for production line of wide and thick plate of Baotou Steel as well as its process control system is between the production management system and basic automation system in the plant, which is mainly responsible for managing production process data. The process control system model of rolling mill is generally divided into control part and non-control part. The emphasis of this paper is to research, analyze, optimize and adjust the rolling moment model of control part. After the optimization, the setpoint accuracy of secondary system model of roughing mill is improved and capacity of roughing mill is further increased.

In this paper, the oxidation and decarbonization as well as formation rule of heterogeneous particles around cracks of web for SS400B hot rolled H beam are studied. The experiment is designed based on the actual working conditions on site as well as oxidation and decarbonization and performance distribution of heterogeneous particles with different processes are analyzed qualitatively and quantitatively with metallographic analysis and energy spectrum. The results showed that there was decarburization around cracks of SS400B hot rolled H beam in the stage of rough rolling, but no heterogeneous particles appeared. It is systematically and comprehensively explained that the oxidation and decarbonization and precipitation of silicon containing heterogeneous particles around cracks are closely related to the composition of steel, process location and thermal regulation combining with domestic study results.

The chemical composition of wire rod for 2 200 MPa ultra-high strength steel strand is designed based on the chemical composition of SWRH82B. The Φ14 mm wire rod is rolled by second heating and cogging with 280 mm×380 mm continuous casting billet. The tensile strength of hot rolled wire rod is increased from 1 150 MPa to over 1 450 MPa by optimizing the cooling rate of wire rod. The target that the strength of steel strand reaches over 2 200 MPa after drawing is realized. The results of industrial trial production showed that the time of soft blow and deep vacuum was the key to control the size of non-metallic inclusions and oxygen content in steel as well as it should be more than 15 min; under the condition of constant casting speed and the degree of superheat is below 35 ℃, the center macrosegregation index could be controlled below 1.15; the ideal microstructure of sorbite could be obtained by controlling moderate cooling rate and optimum cooling rate was 4.89~5.62 ℃/s.

In the paper, it is introduced the detection analysis on non-metallic inclusions in rail head. In order to scientifically characterize the quantity, size and distribution of inclusions, the new method for detecting inclusions is explored. A new vertical detection surface is added by taking the sample position with the K method for cleanliness of oxide in the EN 10247—2017 standard, that is, such two sampling methods as vertical plane and inclined plane are adopted separately. The quantity, size and distribution of inclusions in rail head are statistically analyzed with fully automatic optical microscope as well as the compositions of typical inclusions are analyzed with scanning electron microscope and energy disperse spectroscopy. The distribution and sources of inclusions in the rails of Baotou Steel are comprehensively analyzed, which provide technical support for further improving and controlling the cleanliness of rail steel.

The requirements for surface quality of non-oriented silicon steel are very high as well as such defects as pits and color differences are not allowed on the surface, otherwise, the normal use will be affected. The pits on surface account for a larger proportion in surface quality defects so that product delivery and economic benefits are affected. The analysis results indicated that the accretion for furnace roller was the main cause of pit defects on steel plate. The poor cleaning quality of steel plate, high oxygen content in the atmosphere of annealing furnace and wear of furnace rollers are the main causes of accretion for furnace roller. The accretion for furnace roller is significantly reduced by adopting such methods as improving the cleaning quality of incoming steel plate, optimizing atmosphere environment of annealing furnace and ensuring quality of furnace rollers so that the surface quality of steel plate and qualification rate of silicon steel products have been significantly improved.

In the paper, it is proposed how to select the pipeline material and some matters needing attention in low temperature environment condition by analyzing the lowest design operating temperature of gas pressure piping in the iron and steel industry. The gas pipe in the iron and steel industry is usually with large pipe diameter and low pressure, so it is not pressure piping. With the development of new technologies, some gas pipes with pressure higher than 0.1 MPa are pressure piping. The design of material should be based on the pressure piping code. In the severe cold area, when the lowest design operating temperature of pipe is lower than -20 ℃, the applicability of materials selected for pressure piping in low temperature conditions shall be considered.

In this article, the current conditions and development tendency of cooling bed in the production line of section steel are introduced. A new type of captation and dewatering installation for spray cooling system is designed to solve the problems in applications of spray cooling technology in production of cooling bed. Its layout and structure are mainly introduced combining with design drawings. It is with such characteristics as lower costs, shorter construction period, easier installation and convenient maintenance. With these characteristics, the advantages of spray cooling technology for temperature control in cooling process of section steel could be fully taken, the cooling effect of cooling bed on limited area is better and capacity of cooling bed is improved with the spray cooling technology, which provide reference for upgrading the spray cooling system of online cooling bed.

In order to solve such problems as low efficiency, long time-consuming, large human input and potential safety hazards for the overall replacement of conveying belt in processing line as well as complete the overall replacement of conveying belt safely and efficiently, a set of equipment for automatically changing conveying belt is studied and designed through theoretical analysis and calculations combining with practical experiences. The equipment includes the drive system of old belt, support system of new belt and control system. After the old belt is disconnected, one end is fixed onto drive unit as well as drive system is started to export and roll up old belt, while the old belt is to import new belt. After that, vulcanize and bond the new belt. The practices prove that the automatic replacement of belt could be realized with the equipment as well as the whole process is safe and efficient, which is with wide application prospect.

In this paper, the relatively perfect intelligent weighing system is constructed through adjusting and optimizing the existing business process of weighing, combining with various anti-cheating means as well as making full use of information technology in the new age. Moreover, the weighing information as well as information of door control system and chemical inspection system is integrated combining with respective weighing characteristics of motor truck scale and rail weighbridge to solve such practical problems as the continuously increased variety of weighing materials for materials measurement, more complex business and reduction of weighmen. As a result, the levels of measurement control and informatization management as well as efficiency of flow of materials are improved to meet the requirements of informatization and automation for current weighing system.

The rare earth oxides of lanthanum and cerium are high-value rare earth products, they are usually packed in the packing bags of 500 kg or 1 000 kg and the bagging error is required to be less than 0.05%. At present, the manual bagging is adopted, followed by the charging mode of weighing and compensating. There are such steps for the charging process of each ton bag as hanging bag, charging, carrying, weighing and compensating, so at least 4~5 workers are needed. There are such problems as high labor cost and low production efficiency. The automatic charging machine whose charging error is less than 0.05% and supporting charging basket are developed by adopting such technologies as automation and high-precision measurement and weighing. As a result, the automatic charging for the rare earth oxide products of lanthanum and cerium is realized as well as the problems that complex process of charging rare earth oxide products and several workers needed to operate are solved so that the working efficiency is improved and labor costs are reduced.

The caking index of coal is one of the important indicators for evaluating plasticity of coal. In order to accurately measure the caking index of coal, the influence relations between various components of uncertainties and evaluation results of uncertainties for caking index of coal are analyzed in detail in the paper. The components of uncertainties include such influence factors as the standard uncertainty u(rep) introduced by repetitive tests, standard uncertainty u(m) introduced by weighing mass m of sample with the scale, standard uncertainty u(c) introduced by weighing coke residue during detection process of sample, standard uncertainty u(r) introduced by rotational speed of drum and standard uncertainty introduced by temperature changes of muffle furnace. The uncertainties of measurement results for the caking index of coal are obtained through calculating the standard uncertainties, which provide the basis for scientifically and accurately providing measurement results.

In this paper, the dissolution methods of iron ore and slags are studied. The decomposition method of preliminarily dissolving with hydrochloric acid followed by treating the residue with mixed flux of sodium carbonate-boric acid is applied. The analytical spectral lines with high sensitivity and fewer interferences are determined as analytical spectral lines through optimizing and selecting the analytical spectral lines of lanthanum, cerium, praseodymium, neodymium and samarium by experiments. Moreover, the contents of such five elements as lanthanum, cerium, praseodymium, neodymium and samarium are determined simultaneously with ICP-AES. The results showed that the lower detection limit of lanthanum, cerium, praseodymium, neodymium and samarium in iron ore and slags was 0.005 0%, the upper detection limits of rare earth elements in iron ore were 5% for La, 10% for Ce, 1% for Pr, 2% for Nd and 1% for Sm as well as all the upper detection limits of rare earth elements in slags were 0.500%.