In the paper, the effects of such factors as high load operation, excessive concentration of volatile phenols and microbial poisoning on system stability are systematically analyzed aiming at the practical problem of abnormal increase of chemical oxygen demand (COD) in effluent of biological dephenolization system of Inner Mongolia Baotou Steel Qinghua Coal Chemical Industry Co., Ltd.. The COD in effluent is successfully reduced to standard level within two months so that operation pressure of subsequent advanced water treatment system is significantly relieved by adopting such comprehensive measures as reducing load of inlet, optimizing dissolved oxygen concentration, adding COD degrading bacteria and nitrifying bacteria, supplementing alkalinity to stabilize pH value, adding pulverized fuel ash into oxic tank to adsorb toxic substances as well as adjusting the strategies of sludge return and spoil disposal.

In the paper, the feasibility test of adding purchased high-silicon ore in pellet grate of Baotou Steel is carried out to analyze the changes of performances for green pellets, dry pellets and finished pellets after adding purchased high-silicon ore based on existing configuration of producing iron charge with pellet grate. The results showed that it was feasible to produce oxide pellet by adding purchased high-silicon ore in pellet grate of Baotou Steel. The performances of green pellets could meet the requirements of production processes for pellet of Baotou Steel and changes of grade of iron for oxide pellet are not great, which maintains at around 63.20% after adding 5%~10% purchased high-silicon ore in production with pellet grate. It is suggested to appropriately increase calcination temperature of pellet production in production with pellet grate of Baotou Steel under the condition that proportions of iron ore concentrate of Bayan Obo are 50% and 55% as well as adding 5%~10% purchased high-silicon ore. The compressive strength of oxide pellet produced is over 2 500 N and reduction swelling is below 20%, which could meet the requirements of blast furnace production.

In this paper, the NM1^# wear resistant steel produced by a domestic manufacturer and NM2^# wear resistant steel produced by a foreign manufacturer are selected to be compared and studied by taking rare earth wear resistant steel NM450F of Baotou Steel as the object of study as well as the corrosion resistance test is carried out with alternate immersion test equipment. The results showed that the loss mass of corrosion was 117.98 g/m² and corrosion rate was 1.64 g/(m²·h) for rare earth wear resistant steel NM450F of Baotou Steel so that its corrosion resistance was better than that of like products at home and abroad, NM1^# and NM2^# wear resistant steels. The rust layer of cross section for rare earth wear resistant steel NM450F of Baotou Steel is the thinnest and it appears to be spherical particle with uniform size to spread to matrix and tendency toward corrosion is the smallest.

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.

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 industrial trial production of corrosion-resistant rail is successfully realized through strictly implementing its process system of smelting, continuous casting, heating and rolling. The comprehensive detection for microstructure, mechanical performances and corrosion resistance of trial-produced rail is carried out. The results showed that the tensile strength of rail could reach over 1 050 MPa, top surface hardness of rail head (HBW) was over 300, cross section of rail was uniform perlite and trace amount of ferritic structure as well as lamellar spacing of pearlite was reduced by 21% compared with that of traditional hot rolled U75V rail. Compared with U75V rail, the corrosion resistance of trial-produced rail for simulating coastal atmospheric environment is improved by 45.3% and corrosion resistance of simulating acid rain is improved by 54.9%, which could reach the design indexes.

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 belt conveyer has been widely used in iron and steel enterprises. It is with such characteristics as long transportation time, strong transportation capacity, high safety and efficiency as well as low economic costs. In recent years, it is the key problem how to achieve safety and high efficiency in production process of iron and steel enterprises with the growing demands of transportation capacity for enterprises. The belt conveyer is important equipment for production and development of iron and steel enterprises as well as its safe operation has become an important link in the whole production chain. Once there is the failure of conveyer belt, it will seriously affect normal production of enterprises. In order to ensure the belt conveyer to be operated normally, corresponding preventive measures for tearing of belt should be taken by iron and steel enterprises. In this paper, the causes for tearing of belt for belt conveyer are analyzed, which could provide the basis for solving the problems of belt conveyer brought to production.

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.