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.

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 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, 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 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 rock and ore are divided into three main classes and five subclasses based on iron grade and data of perforating for production in Main Mine of Bayan Obo in recent years as well as distribution rules and space coupling characteristics of contents of F and S in various types of rock and ore are summarized. The research results showed that the main occurrence minerals of element F in Main Mine of Bayan Obo were fluorite and bastnaesite as well as main occurrence minerals of element S were pyrite, pyrrhotite and galena. In terms of distribution of contents of elements F and S, it generally shows the change rule of “increasing first and then decreasing” with the increase of iron grade of ore; in terms of space distribution, elements F and S are most closely related to iron ore, space distribution range of elements F and S is gradually decreased as well as overlapping area is gradually decreased and separated, which shows the distribution characteristic of “alternate zoning with variants” with the increase of contents of F and S.

After the separation of iron and rare earth for ore in Main and East Mines of Bayan Obo, the content of Nb₂O₅ in rare earth flotation tailings is enriched from 0.14% to 0.19%. The bulk flotation is adopted to separate easy-floating minerals in advance so as to reduce the impacts of easy-floating minerals in desilting on subsequent niobium flotation as well as the combined process of flotation and magnetic separation that bulk flotation of tailings-selective flotation of sulfur-flotation of iron-niobium flotation of iron tailings-high intensity magnetic separation of niobium concentrate is adopted to separate niobium industrially aiming at the high content of easy-floating minerals as well as close paragenesis and inclusions of niobium minerals and iron minerals. The bulk flotation is carried out under the conditions that the proportion of size fraction of -0.043 mm for grind fineness is 90%, dosage of TD-V collecting agent is 1.0 kg/t and dosage of depressor, the sodium silicate is 2.0 kg/t, sulfur flotation is carried out under the condition that dosage of butyl xanthate is 1.4 kg/t, iron flotation is carried out under the conditions that dosage of ammonium fluosilicate is 8.5 kg/t and dosage of collecting agent, the SZ fatty acid sodium salts is 0.5 kg/t as well as niobium roughing is carried out under the condition that dosages of CMC, C_5-9 and alum are 1.2 kg/t, 2.2 kg/t and 0.72 kg/t respectively. The niobium concentrate of flotation with grade of Nb₂O₅ of 2.21% is obtained by adopting the niobium flotation process of one roughing and one concentration as well as the niobium concentrate with grade of Nb₂O₅ of 4.41% and sub-niobium concentrate with grade of Nb₂O₅ of 0.96% are obtained through high intensity magnetic separation of 1.7 T so that recovery rate of niobium metal is 34.85% with the combination process of flotation and magnetic separation.

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 propagation model of shock gas is established by taking the shock gas induced by instability of goaf as research background as well as the change rules of propagation rate are analyzed with the laboratory test that simulates shock gas and numerical simulation method. The study results showed that the model of flow past body of shock gas consisted of stages of uniform motion and accelerated motion; the larger the falling height of roof of goaf, the smaller the proportion of duration of uniform motion stage and the larger the proportion of duration of accelerated motion stage. The study results could provide references for prevention and treatment of shock gas disaster induced by instability of goaf.

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.