In the paper, it is introduced the categories of steel for steel structure and steel structure products, standards of steel for steel structure and development status of domestic steel structure production; the development trends of steel structure and steel for steel structure are analyzed as well as how steel manufacturing enterprises can meet the requirements of steel consuming enterprises in processes, products, standards and extended industries to promote the development of steel and industry for steel structures.

In the paper, the SWRH82B wire rod fractured in the process of drawing and twisting line is inspected with such methods as the metallographic structure examination and scanning electron microscope. As a result, the main cause for fracture is the martensite and inclusions in the center. Moreover, the unreasonable production and processing technologies are important causes for the poorer quality of wire rods. The quality of wire rod is significantly improved and the fracture in drawing is reduced by improving the production and processing technologies.

The hydrogen induced cracking (HIC) resistance of X65M pipeline steel products used in the special environment with high H₂S content is analyzed and researched. The control level of w [S] <0.002%, w [P] <0.010%, w [H] <2.0 × 10^-6 and the content of all inclusions in steel less than 1.0 is reached through the mechanism analysis on effects of chemical composition, elemental segregation and nonmetallic inclusions on hydrogen induced cracking, guiding the smelting process and the key process control of S, P, H and oxide inclusions as well as the strict protective casting measures in the continuous casting process. The inspection of hydrogen induced cracking resistance for X65M pipeline steel meets the requirements of product development standards.

Based on the LT gas recovery system with dry process of No. 2 Steelmaking Workshop in CSP Plant of Baotou Steel and combined with the actual production process and equipment operation condition, the main factors affecting the converter gas recovery amount are analyzed. The recovery level of converter gas is improved by eliminating the equipment effects and adjusting process parameters.

In the paper, it is introduced the cost of molten iron is significantly reduced with such measures as adjusting the ore blending scheme, strengthening the management level of blast furnace, improving the operation rate of key equipment and strengthening energy management of 4 150 m³ blast furnace in Baotou Steel based on actively responding to the development strategy of "reducing costs in procedures before iron making and increasing benefits in procedures after iron making".

The paper proposes a method for solving multi-destination transportation route planning problems, and tries to use the structural conditions of Hamiltonian graph/semi-Hamiltonian graph to select appropriate path to construct Hamiltonian path based on the weights of freight and time for different sections of highway so as to select the appropriate path in the transportation process for traversing all destinations without repeating and achieve the most economical transportation effect.

The mineral composition of a magnetic iron ore is complex. In order to make full use of its mineral resources, its process mineralogy was studied and the experimental study of beneficiation process was carried out. The results showed that the ore was with the characteristics of high calcium and magnesium, low silica and aluminum, which belonged to the alkaline ore; the main component of the ore that can be recovered for beneficiation was iron. Through the stage grinding and stage separation－medium intensity magnetic separation recovery process, the iron ore concentrate with the yield of 34.01%, grade of 65.36% and recovery rate of 72.50% can be obtained; through the stage grinding and stage separation-strong magnetic separation recovery process, the iron ore concentrate with the yield of 38.93%, grade of 59.62% and recovery rate of 75.69% can be obtained.

A large number of tailings after beneficiating iron of magnetite are produced every year in Concentration Plant of Baotou Steel. The content of useful minerals such as sulphur and iron in them is higher. The monomer separation is achieved by ore grinding, the sulfur concentrate with the grade of 43.39% and recovery rate of 41.54% as well as the iron ore concentrate with the grade of 63.93% and recovery rate of 8.93% are obtained with the magnetic separation-flotation process. As a result, the pressure of discharging tailings is reduced and the economic and social benefits are great.

In the paper, the orthogonal test was used to investigate the effects of reaction temperature, reaction time and material layer thickness on tailings after beneficiation of rare earth in Bayan Obo with carbon thermal reduction. The results showed that the coke powder with high volatile content was beneficial to obtain the reduced tailings after beneficiation of rare earth with high metallization ratio. The main factors affecting the metallization ratio of the reduced tailings after beneficiation of rare earth were reaction temperature, reaction time and material layer thickness in turn. The optimum test conditions were that the coke powder with volatile content of 12.6% and particle size of 0~2 mm was used as reductant, the reaction temperature was 1 000 ℃, the reaction time was 4.5 h and the material layer thickness was 10 mm.

In the paper, the effects of mold electromagnetic stirring, dynamic secondary cooling water distribution and dynamic soft reduction on the central carbon segregation index, porosity and solidification structure of ingot blank are analyzed by comparing the internal and external quality for ingot blank of heavy rail steel with bloom section produced by 7^#continuous caster after transformation. As a result, the internal quality for ingot blank of heavy rail steel with two bloom sections produced by 7^# continuous caster is fine with reasonable casting speed matched with degree of superheat and the technology of mold electromagnetic stirring + soft reduction. The equiaxed crystal ratio of ingot blank is 52.3%~58.3% and its central carbon segregation index can be controlled below 1.07.

In the paper, it is introduced the Ac₁ of test steel was 659 ℃ and Ac₃ of test steel was 834 ℃, which were determined with CCT curve of 15Cr3MoVTi steel for economical anti CO₂ corrosion oil well tube. Four heat treatment processes are designed based on them. The inspection of mechanical properties after heat treatment showed that the tempering temperature was increased by 60 ℃, the yield strength was decreased by about 130 MPa, the tensile strength was decreased by about 150 MPa and the elongation was improved, but it was not obvious. The impact toughness was significantly improved with the increase of tempering temperature. The impact toughness with tempering of 640 ℃ was 1.4 times higher than that with tempering of 580 ℃.

In the paper, the effect of cooling rate on microstructure and mechanical properties of steel tube after heat treatment furnace was studied by comparing the steel tube with air cooling and water cooling. The test results showed that accelerating the cooling rate of steel tube can increase the nucleation rate at the time of phase transformation and restrain the aggregation and growth of precipitation phase so as to achieve the purpose of grain refinement as well as improving microstructure and mechanical properties.

In the paper, the process of GCr15 bearing steel is improved by optimizing the LF slags and VD furnace process as well as improving the continuous casting process and controlling the rolling temperature. Moreover, its performances were studied. The results showed that the thickness of oxide layer on the surface of GCr15 bearing steel was reduced, the purity of GCr15 bearing steel, the surface quality and hot rolling metallographic structure of wire rod were improved after the process improvement.

In the paper, the cause for lamellar cracking of beam steel during stamping and shearing is introduced. It was found out that there was serious pearlite segregation band in the center of cracked specimen through such detection analysis of metallographic examination and scanning electron microscope. Moreover, there were sulfide inclusion and more hard bulk precipitate associated, the main chemical components of which were such as C, N, Nb and Ti, obtained by scanning electron microscopy and energy dispersive spectrum analysis. The serious pearlite segregation band and the bulky hard precipitate in it have worsened the whole performances of the matrix, so there is lamellar cracking in the center of shearing plane during stamping and shearing.

The article takes X65M pipeline steel produced by Baotou Steel as the research object and discusses the effect of different contents of Nb, finished product thicknesses and sampling directions on the mechanical properties of X65M pipeline steel coiled plate. The data analysis showed that the chemical element Nb could effectively refine the grain of X65M pipeline steel coiled plate. With the same hot rolling process, the thinner the finished product was, the better the low temperature toughness of X65M pipeline steel coiled plate was, the mechanical performances of lateral sampling was significantly better than those of sampling with 30° direction, which will provide a reliable theoretical basis for the actual production and product acceptance of Baotou Steel.

After microwave digestion, Pb⁺² in the sample was oxidized to Pb⁺⁴ by potassium ferricyanide. In the carrying current solution of hydrochloric acid (5+95), potassium borohydride was used as reducing agent and with the characteristics that gaseous hydrides can be produced by the reaction lead and potassium borohydride. The method of hydride generation-atomic fluorescence spectrometry for determining lead in iron containing dust was established. The detection limit of lead in iron containing dust was 0.091 9 μg/L, the upper limit was 0.5%, the relative standard deviation of iron ore standard sample and iron containing dust sample (n = 11) was less than 5.0%, and the standard recovery rate was 97%~104%. The method is fast and simple, which can be used for determining lead in iron containing dust.

With the help of two different methods, the yield strength, tensile strength, elongation after fracture, tensile strain hardening exponent (n) value and plastic strain ratio (r) value of cold-rolled sheet produced by Baotou Steel were determined. The experimental data obtained from the two different methods had been compared. The results showed that the method of automatic measurement with an optical non-contact extensometer was with better reliability and reproducibility.

The production process of iron and steel industry is often a greatly closed system model. If there is a problem at the connections of processes or the equipment components of some links cannot work normally, the iron and steel smelting process can be directly affected. In the paper, it is mainly discussed and analyzed such four aspects as the actual situations, studies effectively carried out, technologies and scientific treatment measures of present fault diagnosis for mechanical equipment of iron and steel smelting.

In the paper, it is analyzed the common faults during the operation of piston air compressors such as insufficient air displacement, abnormal noise or vibration, the air compressor stops running when the pressure air of main air reservoir does not reach constant pressure, the air compressor does not stop running when the pressure air of main air reservoir is higher than the adjusting pressure of compressor governor and the air compressor is still not running when the pressure air of main air reservoir is lower than the adjusting pressure of compressor governor. Moreover, the corresponding measures are put forward to improve the service life and efficiency of compressor so that the safe operation and productions are ensured.

The 1500/300 crusher is only with the simple thermometer and pressure gage, so it wastes time and energy for operators to observe and operate, which is not convenient. The operating condition, working condition of labor, job security, efficiency and service life of 1500/300 crusher are improved by installing the advanced, stable automatic supervisory control device on the original device so as to achieve the excellent lubrication.

Due to the design defects of steel structure on furnace top of 4^# blast furnace in Baotou Steel, it is necessary to make special sling for replacing the distributing device. The preliminary design and analysis of sling are carried out with the Inventor software. The stress distribution, displacement deformation and security coefficient of sling are calculated with the Inventor stress analysis module after modeling of sling so that the actual problems on site are successfully solved.

The article starts with the tilting control process, the design and principle of tilting control system for melting furnace are analyzed from the control principle, hardware design (including the actuator of tilting and the hardware design of tilting controller) and software design of tilting control system. The researches of tilting control principle and casting curve design have played an active role in optimizing the metallic structure of casting piece and improving the uniformity of product thickness for automation of equipment.

In the paper, the working principle, structure and the problems of evaporative air cooler, the cooling facility for closed-cycle water system of 6^# blast furnace in Baotou Steel in operation in winter are elaborated as well as the solutions are put forward. The loss of new water in production is reduced and the utilization rate of circulating water for 6^# blast furnace is improved through transforming and optimizing the water tank of air cooler, which is further generalized.

In the paper, the causes for nodulation of furnace roller are analyzed based on the characteristic of modified Sendzimir hot galvanizing line of Baotou Steel. As a result, the nodulation of annealing furnace roller is effectively controlled by adjusting and optimizing all the technological parameters and associated equipment which might cause the nodulation of furnace roller. Moreover, the causes, treatment and preventive measures for nodulation of furnace roller are summarized.

In the paper, the installation method of large steel tubular super high tower is systematically elaborated with the installation project for blow-down cylinder tower of purification device for 0.68 million t/a coal-based new material project of Shenhua Group in Xinjiang as background. The installation process is optimized in the construction so that the construction efficiency and quality are improved as well as the economic benefits are very good, which has accumulated experiences for the constructions of similar projects in the future.

In the paper, the turning methods for E stand roller of CCS rolling mill are introduced. The roller consumption is reduced and the turning efficiency is further improved by the comprehensive improvement of professional knowledge level for theory and practice of turners as well as further strictly controlling the whole manufacturing process of parts with such details as tool path determination, parameter setting, turning procedure programming and simplification.