The continuous cooling transformation laws of X120M pipeline steel is studied with Gleeble 1 500 thermal simulated test machine as well as it is with controlled rolling and controlled cooling in laboratory. The results indicated that the microstructure of test steel was mainly lower bainite and martensite when cooling rate was at 20~50 ℃/s. When the finish cooling temperature of test steel is at 380 ℃, its yield strength is 900 MPa, tensile strength is 1 015 MPa, elongation is 18%, impact energy at -30 ℃ is 180 J and shearing area of drop weight tear test at -20 ℃ is 100%. The mechanical properties could meet the standard requirements.

In this paper, the continuous casting billet of low temperature Hi-B steel, metallographic structure and texture of plates after such processes as hot rolling, normalizing, cold rolling, decarburizing annealing and high temperature annealing are observed with metallographic microscope and X-ray diffractometer (XRD) as well as the evolution laws of microstructure and texture in the whole process are analyzed. The results showed that the macrostructure of continuous casting billet was mainly columnar crystal and proportion of equiaxed crystal zone was 7%~12%; microstructure of hot rolled plate was composed of alternant banded structure of ferrite and pearlite; microstructure of normalized pickled plate was composed of fine crystal zone and recrystal microstructure. The textures at 1/8 of thickness of hot rolled plate and normalized plate are mainly Goss texture and brass texture as well as strong Goss texture is formed with the secondary recrystallization after high temperature annealing.

The drop weight tear test (DWTT) is used to test the toughness of materials, mainly for studying the low-temperature toughness of metal materials. In the paper, the microstructure and morphology of samples corresponding to different area proportions of brittle fracture are compared and analyzed with optical microscope aiming at the unqualified DWTT properties of products during trial production process of heavy gauge X80M hot rolled steel strip. The composition segregation in thickness direction of casting blank is tested. It is found that the severe segregation in thickness direction of steel strip is the main factor influencing the DWTT properties by analysis. The center segregation of casting blank and DWTT properties of product are improved effectively by adjusting the arc alignment precision of segment and optimizing the specific water amount of continuous casting machine so that the goal of stable production of hot rolled steel strip for heavy gauge X80M pipeline steel is realized.

The effects of microstructure of high-strength anti-seismic fire-resistant H beam for building structure on its strength, toughness and high temperature strength are studied with such analysis means as TEM (transmission electron microscope), metallographic microscope and EBSD (electron back-scattered diffraction). The results showed that the controlled rolling and controlled cooling were not needed under the premise of reasonable chemical composition design, two-phase structure of air cooling bainite and ferrite for test steel after hot rolling was obtained. It is found by observing the microstructure after holding at 600 ℃ for 3 hours that there is nano-level interphase precipitates in ferrite and their line spacing is about 24~34 nm. For the hot rolled high-strength anti-seismic fire-resistant H beam for building structure, its yield strength≥500 MPa, elongation≥22%, yield ratio≤0.85, impact energy at -20 ℃≥34 J and yield strength after holding at 600 ℃ for 3 hours≥310 MPa.

In the paper, the general situations of production processes for 380HBW grade LH on line heat treated rail exported to Mexico are introduced. Its batch production is successful by microalloying component design, control of high cleanliness for smelting process as well as accurately regulating and controlling the on line heat treatment process of rail. All its performances could satisfy the technical requirements of users and requirements of AREMA standard as well as pass the SGS international testing and certification so that it could satisfy the operating requirements of freight train with great axle load on heavy haul railway abroad. It has been exported to such countries as Mexico, Australia and America.

The characteristics and change rules of wear behavior for rail with different load conditions are analyzed through experimental study on wear of on line heat treated U20MnH rail combining with the morphology features of wear surface and profile for samples observed by microscope and scanning electron microscope. The results showed that the wear loss of on line heat treated U20MnH rail was significantly reduced with increase of load under load conditions of 1 200 N, 1 500 N and 1 800 N respectively.

In the paper, it is introduced the operation systems of cloud computing platform of Baotou Steel increase continuously with the development of enterprise informatization so that the time of operation and maintenance and routing inspection is long as well as efficiency is low. The regular operation and maintenance and routing inspection of server of operation systems are realized so that their efficiency is improved, hidden troubles are found out and eliminated timely as well as stability of system operation is improved by compiling the Shell script.

In this paper, the production practices on improving automatic casting ratio of ladle are introduced as well as various improvement measures are proposed through deeply analyzing the factors influencing automatic casting of ladle combining with production practices. The practices showed that the automatic casting ratio of ladle could be increased to over 99.5% so that the goal of reducing unplanned products produced by cast billets with burning oxygen is achieved through improving the quality of stuffing sand, optimizing sand filling device, formulating plan of replacing nozzle, strictly controlling time of steel filling according to steel grade, preventing back flow of steel slag and shortening standing time of liquid steel.

In the paper, the detection method of magnesium content in silica-based composite material is studied and its purpose is to accurately detect magnesium content in the process of preparing silica-based composite materials so as to control the content of magnesium silicate in final product. During the experiment, the method for determining magnesium content in magnesium silicate-carbon-encapsulated silicon oxide composite material with the inductively coupled plasma atomic emission spectrometry (ICP-AES) is established. Finally, it is verified that the detection limit is 0.004 mg/L, relative standard deviation of detection results is less than 5% and linearly dependent coefficient is above 0.999 so that this method is satisfied with the test of magnesium content.

The transformation structure and critical points of phase transformation for rare earth alloyed high carbon wear resistant steel as well as continuous cooling transformation (CCT) curve of undercooled austenite at different cooling rates are studied by metalloscope, field emission scanning electron microscopy and quenching dilatometer. The results showed that the critical points of phase transformation were Ac₁=742.6 ℃, Ac₃=816.5 ℃ and Ms=307.0 ℃. When cooling rate is less than 0.4 ℃/s, the microstructure is a small amount of ferrite+pearlite; when cooling rate is 0.4 ℃/s, the microstructure is single-phase pseudo eutectoid pearlite; when cooling rate is greater than 0.5 ℃/s, the microstructure is gradually transformed to martensite; when cooling rate is greater than 4 ℃/s, there is only the microstructure of martensite+retained austenite in the steel.