In this paper, the whole process flow of development, production and applications for 500 m finished rail in iron and steel enterprises is studied. The large-scale, standardized and continuous production technological system of 500 m rail is established through production process control of series of rails as well as optimization, adjustment and control of joints combining with single system quality control. The production operation modes of 100 m and 500 m rails are realized so that the goals of the shortest transfer process of production materials as well as low carbon and green for long rails have been realized in the enterprise. The control goals that sulphur content of heavy rail steel≤0.005%, ratio of equiaxed crystal for continuous casting billet reaches 42% and segregation index of manganese for rail≤1.03 are realized through deep desulfurization of refining, tundish metallurgy and narrow composition control; dimensional deviation of rail height at both ends of head and tail for 100 m rail is ensured to be ≤0.40 mm as well as differences of high-low points at the ends are ≤0.20 mm based on high precision rolling technology of rail; joint quality is effectively improved and qualified rate of joint could reach over 99% combining with rail production quality improvement and welding process optimization.

In the paper, it is elaborated comprehensively integrate idea of green development in procurement activities, drive green development of procurement by means of digital intelligence tools, promote green manufacturing with green procurement, build brand of green digital intelligence supply chain, guide and drive green, low carbon and circular synergetic development of upstream and downstream enterprises as well as accelerate green and low carbon transformation development of the entire chain for iron and steel enterprises from the perspective of modern supply chain, which could play a role of demonstration and leading for state-owned enterprises to achieve the national strategic goal of “carbon peaking and carbon neutrality” as well as provide strong supports for accelerating establishment of world-class enterprise.

In the paper, the diversified application practices of such modern intelligent technologies as the Internet of things, big data, unmanned aerial vehicle and artificial intelligence in safety production management are deeply discussed based on their advantages. It is with such advantages as improving working efficiency, reducing accident risks, providing intelligent decision supports and saving costs to apply the intelligent technologies in safety production. As a result, the level of safety production management in enterprises is improved significantly with the intelligent technologies, which is helpful to optimize safety production management system. This paper is aimed to provide the application practice cases for related fields and promote the intelligent upgrade of safety production management.

The samples are prepared with fused bead method, contents of calcium fluoride, silicon dioxide, phosphorus and sulfur in fluorite are determined with wavelength dispersion X-ray fluorescence spectrometry as well as effects of such factors as type of flux, dilution ratio, weighing sample, melting temperature and melting time on determination results are analyzed so that optimal experimental conditions are determined. Meanwhile, the working curves of each element are drawn using standard samples and self-made control samples as well as correlation coefficients all reach over 0.999. The precision experiment showed that the relative standard deviation (RSD, n=10) of determination results for contents of calcium fluoride, silicon dioxide, phosphorus and sulfur in fluorite was 0.23%~4.80%, the accuracy experiment showed that the difference values of measured values, standard values and chemical analysis values for contents of calcium fluoride, silicon dioxide, phosphorus and sulfur in standard sample of fluorite and control sample of wet chemical analysis were within the range of allowable deviation for the methods of GB/T 5195.5—2017, GB/T 5195.6—2006, GB/T 5195.1—2017 and GB/T 5195.8—2006. The method is with shorter analysis process, higher sensitivity and certain promotion and application value compared with wet chemical analysis.

In the process of moving toward high-quality development for iron and steel industry, operating efficiency and energy consumption of steel rolling heating furnace, the core production equipment, could directly affect enterprise competitiveness. The traditional monitor mode relied on manual inspections and experience judgment so that there are such problems as lagged temperature control, low combustion efficiency and isolated data island, which could not meet the requirements of precise and intelligent productions for modern industry. In this paper, the intelligent monitoring system for steel rolling heating furnace are deeply studied, background and significances of developing the system are elaborated as well as deficiencies of traditional monitor mode are analyzed. The framework of intelligent monitoring system for steel rolling heating furnace is established based on advanced sensor technology, the Internet of things, big data analytics and artificial intelligence algorithm as well as hardware structure and software function modules of the system are introduced in detail. The remarkable effects on improving precision of temperature control for heating furnace, optimizing combustion efficiency, reducing energy consumption and ensuring production safety of the system are demonstrated through practical application cases as well as the challenges faced in process of applying the system and future development directions are discussed, which could provide the theoretical and practical references for intelligent upgrade of steel rolling industry.

In this paper, the construction technology of stay cable for Lanzhou Chaijiaxia Yellow River Bridge is discussed. The general thinking of construction is proposed, construction equipment is designed, selected, stretched and hung up as well as key points of construction and solution are determined so that the technical problems in construction of stretching and hanging up stay cable under complicated condition are solved through systematic study of construction scheme for stretching and hanging up stay cable, which could provide reference examples for the similar constructions in future.

The effects of dimension precision of rails on stable operations of high speed train are important as well as the fluctuation of bottom width size for 60 kg/m 100 m high speed rail influences its production, delivery and use. The control methods are proposed from such four aspects as heating of billets, pass design, rolling parameters and tension of continuous mill through analyzing the main influencing factors that cause fluctuation of bottom width size for high speed rail in rolling process. The implementation effects showed that the fluctuation range of bottom width size for rail could be narrowed as well as product quality and production efficiency of rail could be improved with correct and appropriate control methods.

The equipment in production line of rolling is with such characteristics as large size, long distance and high accuracy requirements. In the paper, the combined measurement technologies of laser tracker and total station are studied aiming at the problem that ranging accuracy of total station is relatively low. When lay the control network, such advantages as high angle measurement accuracy and long measuring distance of total station as well as high ranging accuracy of laser tracker are made full use to minimize measuring errors and complete measurement of high accuracy equipment in production line of rolling without complicated calculations.

In the paper, the effects of adding rare earth element Ce into Cr12MoNiNb mold steel on its inclusions and mechanical properties are studied. The morphology, size and composition of inclusions are observed and measured with scanning electron microscope, energy spectrometer and field emission electron probe. The size, quantity and precipitation law of inclusions are statistically analyzed with analysis software as well as hardness and room-temperature impact energy of samples are measured with Vickers hardness tester and impact tester. The results showed that circular or elliptical composite inclusions containing rare earth were formed in the mold steel after adding 0.002 8% of rare earth Ce and quantity of inclusions was decreased by 21.43% compared with those of the steel without adding rare earth elements so that liquid steel was purified; average size of inclusions was decreased from 3.95 μm to 3.13 μm, which was decreased by 20.76%. The hardness and room-temperature impact energy of mold steel are increased by adding rare earth Ce. Its Vickers hardness (HV) is increased from 263.0 to 283.0 and room-temperature impact energy is increased from 16.65 J to 20.05 J, which is increased by 20.42%.

In this paper, two types of online as-heat-treated pearlite rails are tempered. The optimal tempering process of two types of high-strength heat-treated rail is obtained based on the changes of mechanical properties and microstructure for the rails under different tempering temperatures. The results showed that the comprehensive mechanical properties of rail could be improved by low temperature tempering within the range of 200~350 ℃. With the increase of tempering temperature, residual stress of rail web tends to be decreased. The residual stresses of rail web for the two types of rail are 45 MPa and 32 MPa respectively with tempering at 350 ℃, which are decreased by 63.4% and 80.6% compared with those before tempering. The hardness, toughness and plasticity of tempered rail are improved with the increase of tempering temperature. The hardness is significantly increased with the improvement of plasticity and toughness. The tread hardness (HBW) of rail is increased by 13 and 8 respectively with tempering at 350 ℃ as well as the tempered rail is still with typical perlite structrure.