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%.

The microstructure and texture of ingot blank, hot rolled steel plate, cold rolled steel plate and annealed plate are studied with the optical microscope (OM) and X-ray diffractometer (XRD) as well as the magnetic properties are tested with magnetic tester. The results showed that the central equiaxial crystal ratio of continuous casting billet could reach 44.5% with electromagnetic stirring, surface structure of hot rolled steel plate was with perfect recrystallization by adopting high temperature coiling process and average grain size was 28.5 μm as well as the microstructure in the center of hot rolled steel plate was with interlaced composition of recrystallized grain and long strip shape banded microstructure and average grain size of annealed plate was 74.2 μm. The distribution of texture in the thickness direction of hot rolled steel plate is uneven. The surface textures are mainly brass texture and goss texture, textures of 1/4 layer are mainly {100} and {112} components, central textures are mainly {100} and {110} components as well as textures of annealed plate are mainly composed of {111} and weaker {100} planar textures. The magnetic property of sample plate of finished product randomly drawn is measured with the Epstein square method and the results could meet user requirements.

The 4^# slip mass in area D of the main stope of Bayan Obo Iron Mine is above the fixed transport corridor of 1 458 m to 1 430 m of the main line of stope as well as it is mainly composed by piling up loose gravel and dimension stone so that the larger and extremely unstable slope structure is formed, which directly threatens the safety production of lower part. If it is not treated in time, it will cause to suspend production in the whole stope. The treatment scheme of taking the 1 542 m platform as dividing line of step by step governance, adopting the method of cutting slope and reducing load at upper part as well as adopting the cleaning and reinforcement of slope at lower part is established through actual investigation and analysis of current situations for 4^# slip mass. The expected goals and effects are completely achieved after implement the treatment scheme so that the conditions of safety production at lower part are effectively improved, which could be as reference in future slope treatment.

The fuel ratio is the main economic and technical index for blast furnace ironmaking, so it is of great significance for energy conservation and emission reduction of enterprise to reduce it. In this paper, the reasons for high fuel ratio of 6^# blast furnace of Baotou Steel are analyzed. After the overhaul and blow-in of 6^# blast furnace, the fuel ratio of blast furnace is reduced through taking such measures as tackling key problems in improving production to stabilize the feed of blast furnace, improving quality of raw fuel, strictly controlling differential pressure in blast furnace operation, adjusting charging system, stabilizing high blast temperature, reasonable use of enriched oxygen and coal injection as well as strengthening basic management. The cumulative fuel ratio in 2021 was 545.84 kg/t, which was 10.58 kg/t lower than that in 2020.