In the paper, the chemical compositions of BT110V steel for high-strength and high-ductility casing are designed based on the problem that special casing for deep well of oil and gas exploitation is with high strength and low ductility by giving full play to the effects of alloying elements in steel. Moreover, the production process of BT110V high-strength and high-ductility casing is formulated with the existing production equipment of seamless steel pipe. The mechanical properties, hardenability and microstructure of trial-produced BT110V high-strength and high-ductility casing could all meet the technical requirements. For the BT110V high-strength and high-ductility casing with the specification of Φ193.68 mm×10.92 mm, failure strength caused by internal pressure is 58.6% higher than that of the technical requirement, failure strength caused by external pressure is 38.3% higher than that of the technical requirement and joint strength is 26.6% higher than that of the technical requirement. During the process of industrialized promotion and application, all indexes show good stability and the modifying effect of rare earth microalloying on inclusions is obvious.

The edge drop of cold-rolled strip directly affects width accuracy and edge quality of product, it is especially prominent under the conditions of non-oriented silicon steel with wide specification and limited rolling reduction. In the paper, the integrated three-dimensional finite element model coupling with roller-strip steel is established based on the 1 780 mm 6-high CVC (continuously variable crown) rolling mill. Such aspects as geometric modeling, mesh refinement at the edge and contact zone between rollers, boundary constraint, friction contact setting and multi-step load incremental control of this model are optimized. Compared with the measured sectional contour of the unit, the RMSE (root mean square error) of simulation result is 6.85 μm and MAPE (mean absolute percentage error) is 1.26%, which indicate that the model is with higher prediction accuracy. The influences of thickness, width and reduction ratio of strip steel as well as deformation resistance of materials on the formation laws of edge drop are systematically analyzed. The transverse metal flow at the edge could be significantly amplified with the increase of thickness or reduction ratio so as to aggravate edge drop; transverse flow at unit width could be reduced by increasing width of strip steel so as to weaken edge drop to some extent; it is beneficial to inhibiting metal flow at the edge to increase deformation resistance so that edge drop and its sensitivity to reduction ratio are reduced. The simulation system of limited conditions is established based on this to investigate the comprehensive abilities of regulation and control of roll bending forces of working roll and intermediate roll as well as amount of roll shifting for intermediate roll to edge drop. The results showed that the effects of working roll bending on edge drop control were the most significant, the average control effect was approximately 3.5 times of that of intermediate roll bending and about 30 μm of linear regulation amplitude could be achieved for intermediate roll shifting at its positive and negative limiting positions. The efficiency and sensibility of different control methods are with quantitative evaluation by introducing the efficacy coefficients of edge drop control, which could provide the theoretical basis and engineering references for optimization design of roll shape for 6-high CVC rolling mills and formulating the process of edge drop control for silicon steel with wide specification.

For the production line of comprehensive utilization of oxidized ore resources in Bayan Obo, iron and rare earth separations are carried out after two-stage closed-circuit grinding of raw ore as well as fluorite separation is carried out when rare earth tailings are ground to the proportion of particle size<30 μm is over 70%. The multistage grinding causes significant increase of mechanical secondary slime as well as electrostatic repulsion between fine slime particles is strengthened so as to inhibit sedimentation when circulating wastewater is with alkalescence by adding a large amount of sodium silicate and foaming agent during beneficiation process, the silica sol generated by sodium silicate is absorbed on the surface of fine slime particles so as to form coating layer. As a result, the hydrophobic property of particle surface is reduced and affinity of it and water is enhanced so that fine slime particles are more dispersed and stable as well as the content of suspended solids (SS) in water reaches over 5 000 mg/L. The beneficiation wastewater is treated with the process of magnetic coagulating sedimentation-stirring-flocculation-stirring as well as the content of SS in wastewater is reduced to 69 mg/L and pH value is basically unchanged. The flotation test is carried out for circulating wastewater after treatment, it is better for circulating wastewater after treatment to improve the grade and metal recovery rate of iron, rare earth and fluorite than those for circulating wastewater without treatment as well as the dosage of reagents in every link is significantly reduced.

The slow-speed actuating device is changed from built-in brake motor to external hydraulic brake so that the burning loss of motor is effectively eliminated, operation stability of equipment is improved and repair time is significantly reduced aiming at such problems as low operation reliability, short service life of key components and leakage of discharged ore for ball mill in grinding process of baiyuneboite; the protection plate of liner plate for shell and end cover are optimized separately with the composite material of lipid complex rubber and plastic and wear resistant rubber so that their service life is increased to over 2 years as well as long lasting and reliable protection of main body of equipment is realized; the structure is improved and wear resistance is optimized for drum screen at the end of discharging ore so that its service life is increased to over 6 months, replacement of sieve mesh and reuse of framework are realized as well as the problem of damage for flow passage component of slurry pump caused by leakage of steel ball is successfully solved. The practices show that the above improvement measures are with significant engineering application values for ensuring safe production and improving overall production efficiency of mine.

After large proportion of wet quenched coke is added into the large blast furnace of Baotou Steel, there is fluctuation of blast furnace conditions, yield is reduced by 16.26% and coke ratio is increased by 7.23%. The changes of coke quality, metallurgical performances of sinter, load of harmful elements in blast furnace and corresponding changes of blast furnace conditions are analyzed, which could provide references for smelting of adding large proportion of wet quenched coke into large blast furnaces next.

Under the background of increasing competition as well as transformation and upgrading for global manufacturing industry, deeply integrated intensive production and standardized manufacturing have become the key path for improving industrial competitiveness. In this paper, it is systematically explored the theoretical framework, methodology and application practices for integrating innovation of intensive production and standardized manufacturing, which mainly include their core connotation and theoretical foundation as well as establish integrating innovation method system; the challenges, solving strategies and comprehensive benefits in application process of this innovation method are deeply analyzed with the empirical analysis method by taking a group company of Chinese steel industry as the case. The study results showed that the production period and operating costs could be significantly reduced as well as stability of product quality and utilization efficiency of resources could be improved by cooperation of intensification and standardization. Finally, the future development trend of this mode under the background of intelligent manufacturing is expected in order to provide theoretical and practical references for high-quality development of manufacturing industry in our country.

The key influence factors of the entire process of pretreatment, phosphating and electrophoresis are studied through system experiments as well as the influencing mechanisms of such key parameters as surface roughness of plaque, peak density, processing modes of rust preventive oil and pH values of washing process on coating performances are revealed aiming at the coating compatibility issues of deep drawing automobile steel. The research results showed that pH value of washing process over 8.5, cooperating effects of reasonable surface roughness of plaque (Ra≈1.2 μm) and peak density (RPc≥90 cm^-1), avoiding manual oiling treatment of plaque are the core of forming high-quality phosphating film and improving corrosion resistance of electrophoretic coating film. This study provides universal process optimization directions and key points of quality control for optimizing the coating compatibility of automobile steel sheets.

In this paper, the causes of surface blistering of electrophoretic coating plate for DC04 cold rolled automobile steel after 60-cycle cyclic corrosion resistance test are analyzed with scanning electron microscope and energy dispersive spectrometer. The test results showed that the size of phosphating phase in blistering area was approximately 10~25 μm, while that in non-blistering area was about 2~3 μm; such characteristic elements of phosphating phase as Zn and P were not detected in blistering area, while the phosphating film was bound tightly with matrix and electrophoretic coating film in non-blistering area as well as there were such characteristic elements of phosphating phase as Zn and P in phosphating film. The binding force of matrix, phosphating film and electrophoretic coating film is reduced by coarse phosphating phase as well as the channel for extension of corrosive liquid is provided so that there is surface blistering of electrophoretic coating plate for DC04 cold rolled automobile steel after 60-cycle cyclic corrosion resistance test finally. The incomplete degreasing during pretreatment of automobile steel and there is residual oil on the surface may be the causes for the abnormal growth of phosphating phase.

The 300 MPa grade enamel steel is with low-carbon composition design, such alloy elements as Mn, Nb and Ti are added, tapping temperature of heating furnace in hot rolling is controlled at 1 200~1 230 ℃, finishing temperature≥890 ℃, coiling temperature≤580 ℃, cold rolling reduction ratio≥65% as well as continuous annealing temperature is selected to be 830 ℃. The yield strength of developed high strength enamel steel is 367 MPa, which is still over 300 MPa after enameling as well as its microstructure mainly consists of uniform equiaxed ferrite with Fe₃C and dispersed TiC precipitates. The TiC could effectively pin grain boundaries to prevent grain coarsening during high temperature treatment process. TH (sensitivity of resistance to scute burst) is 6.80~7.23 min/mm², which could meet the requirements of EN 10209—2013 standard (TH>6.7 min/mm²).

In order to study the weldability of wind power steel Q420ME, the SH-CCT (simulated heat-affected zone continuous cooling transformation) curve is determined, temperatures of A_c1 and A_c3 for wind power steel Q420ME are 690 ℃ and 920 ℃ separately. The SH-CCT curve analysis shows that the bainite transformation occurs first, followed by martensite transformation during cooling process as well as the microstructure is bainite and martensite when cooling rate is 10~40 ℃/s. With the increase of cooling rate, the content of bainite is decreased, while content of martensite and hardness of wind power steel Q420ME are increased.

In this paper, the effects of different chloride ion (Cl^-) concentrations on corrosion behavior of T91 steel treated by indentation method in the neutral salt spray environment are studied. The corrosion test of 48~288 h for indentation specimens is carried out with NaCl solutions of concentrations of 10% and 15% under the standard neutral salt spray test conditions. It is found that the corrosion weight loss in the environment of 15% NaCl is higher than that in the environment of 10% NaCl through analyzing the corrosion weight loss, corrosion morphology and corrosion products as well as the difference between them is increased with the extension of corrosion time, which reaches the maximum value (0.008 5 g) at 288 h. This proves that the corrosion effects of environment with high Cl^- concentration on T91 steel are stronger and they are obvious with time accumulation. The observation results of scanning electron microscope showed that the indentation was more easy-corrosive and the more the Cl^- concentration, the more serious the corrosion was, which indicates that the corrosion resistance in this area is significantly reduced by stress concentrations (dislocations, microcracks etc.) introduced by indentation so that it becomes the sensitive area where corrosion occurs preferentially.

In this paper, the effects of different heating temperatures and holding time on original austenite grain size are studied by taking X80 pipeline steel as the research object. The results showed that the original austenite grain size of X80 pipeline steel holding for 1 hour at different heating temperatures was gradually increased with the increase of heating temperature; the austenite grain was coarsened rapidly with the effect of driving force of high grain boundary at initial stage of holding under the soaking condition of 1 180 ℃ as well as the average size was increased from 15 μm to 50 μm within 1 hour, which showed the high sensitivity to time.

In this paper, the design of new economical steel grade, laboratory researches and industrial trial production of BNS line pipe in sour service are carried out. The results showed that such properties as the yield strength, tensile strength, elongation, impact properties and Vickers hardness of trial-produced steel pipe (as-hot-rolled and after normalizing treatment of 890 ℃) could meet the requirements of API 5L standard. After normalizing treatment of 890 ℃, the low temperature impact toughness of steel pipe is significantly improved and its ductile-brittle transition temperature is reduced from -10 ℃ (as-hot-rolled) to -50 ℃ (as-normalized condition) as well as its banded structure is improved and grain size of matrix is refined from grade 7(as-hot-rolled) to grade 8.5 with normalizing treatment.

In this article, the construction technology of synchronous sliding for steel box girder of Lanzhou Chaijiaxia Yellow River Bridge is comprehensively summarized. The construction scheme of “assemble on both shores, incremental launching toward each other and accumulate sliding section by section” is systematically proposed through researching the synchronous sliding technology for steel box girder. Moreover, such technical problems as the sliding route, setting of temporary piers, assembly of sections for girder of slippage and length of steel launching nose are solved through the BIM (building information modeling) technology. The control measures for key technologies of sliding construction are sorted out in this paper, which could provide references for sliding constructions of girder for cross-river cable-stayed bridge under complicated conditions.

The mobile robot is widely applied in various complicated terrain environments, so the requirements of travelling speed and capacity of passing complicated terrain for travelling mechanism are higher. In the paper, the interactions and problems existing between components are determined with function analysis tool as well as the key problems are determined with causal chain analysis tool in modern TRIZ (Theory of Inventive Problem Solving) theory system by taking wheeled travelling mechanism as the prototype system as well as analyzing its advantages and disadvantages. The above problems are solved and 10 conceptual proposals are obtained through combining such tools as ideal final result, cropping, substance-field model, physical and technical contradictions with inventive principles. Finally, the scheme of deformable tire is determined to be the optimal technical scheme and modeling design is carried out.

The traditional detection robot of water surface environment is limited by such problems as difficult deployment of vessel and susceptibility to effects of weather conditions so that the operation costs are high. In the paper, a solution is proposed. The detection robot of water surface environment autonomously enters water to perform underwater operation tasks after deploying it on land. The solution does not need vessels to support, allows rapid response to operational requirements in lakes, reservoirs and shallow areas, which is suitable for replacing conventional detection robot of water surface environment to perform underwater operations when it is difficult to deploy vessel as well as it could provide the solution with light weight and high maneuverability for underwater task operations.

In this paper, the development situations and trend of automatic control system for blast furnace are deeply analyzed as well as such existing problems as aging of software system and complex operation methods are pointed out. With the development of artificial intelligence (AI) technology, it becomes a new direction to combine automatic control technology with AI. Under the background of carbon peaking and carbon neutrality, higher requirements of accuracy and stability of control system for blast furnace are put forward for applications of hydrogen metallurgy technology as well as energy management and digital transformation become the new issues. Meanwhile, the development of control system for blast furnace prompts knowledge structure of operating personnel to transform to integration as well as more high qualified and professional integrated talents are needed. The research showed that the process control of blast furnace in our country could reach the world-class level by continuously improving the interactions of theories and practices, cultivating professional talents and optimizing the system.

The cold area process is the key link in production of heavy rail and section steel, its operating efficiency and level of intelligence directly affect the quality and production cost of final products. With deep implementation of the national development strategy for high-end and intelligent manufacturing industry, it has become the inevitable choice for steel enterprises to enhance their core competitiveness to improve the levels of automation and intelligence of production lines. In the article, the integrated applications of such key technologies as industrial visual recognition, precise length measurement of dynamic steel billets with laser, intelligent voice alarm and intelligent die for first-forming based on AI (artificial intelligence) are the core content as well as their implement methods and application effects are elaborated, which could provide the practical references of technology applications for intelligent transformation of the same type of production lines in the industry.

As the core component of electrocoagulation technology, the structure and performances of metal plate directly determine its treatment efficiency and operating costs. Traditional single metal or conventional bimetallic plate is with such problems that electrode is easy to be passivated, corrosion rate is rapid and reaction efficiency is low. In this paper, the advantages of gradient alloying design process for bimetallic plate are focused as well as its feasibility and unique advantage of key indexes are demonstrated from such aspects as proportion of metal materials, inhibition effect of electrode passivation and removal rate of fluorine through actual data of operations under the same reaction conditions.

The carbon content in high-carbon ferrosilicon is determined with high frequency induction combustion infrared method. The optimal analysis conditions are determined through a series of experiments such as weighing sample as well as addition amount of pure iron, tin granular and tungsten particle. The experimental results showed that the molten state of sample was good, relative standard deviation of precision experiment results was 0.59% and adding standard recovery was 99.16%～100.34% with the addition sequence of 1.50~1.70 g pure iron, 0.08~1.20 g sample, 0.30 g tin granular and 1.30~1.50 g tungsten particle, which could meet the requirements of chemical analysis. This analytical method is with simple operations, rapid analysis as well as high accuracy and precision, which could meet the requirements of incoming inspections of high-carbon ferrosilicon.