In the detection of building foundation piles, crosshole sonic logging is the important detection method to judge the integrality of pile body for cast-in-place concrete pile. In this paper, it is introduced the basic principle and judgment basis of detecting integrality of pile body with crosshole sonic logging as well as summarized the process flow and matters needing attention of on-site detection by taking the project of archives center in a city as an example, which provide accurate detection data for the quality of foundation pile in project.

In order to explore the effects of adding Indian powder ore on the production efficiency and quality of sinter, the experimental studies on basic sintering characteristics and sinter pot of Indian powder ore are carried out respectively. In the experiment, the current iron charge configuration of 2^# Sintering Workshop of Iron-making Plant is taken as the datum point as well as the Mongolian powder ore and high-silicon Brazilian coarse powder ore are replaced by Indian powder ore respectively. The performances of Indian powder ore are comprehensively evaluated from such aspects as the chemical composition, size composition and quality index of sinter, which provide the basis for determining appropriate adding proportion.

In the paper, the theoretical inter-hole delay time and theoretical delay time between rows for such three types of lithology as iron ore, dolomite and slate in firing network are calculated by averaging as well as reasonable parameters are formulated to organize and launch bursting test through analyzing domestic and foreign rock breaking theory of millisecond blasting. The study showed that the reasonable inter-hole delay time of dolomite was 32 ms and that with blast block≤800 mm accounted for 98.17%; reasonable inter-hole delay time of slate was 40 ms and that with blast block≤800 mm accounted for 91.11%; reasonable inter-hole delay time of iron ore was 28 ms and that with blast block≤600 mm accounted for 82.16%. The proportions of qualified block corresponding to reasonable delay time of each lithology are increased.

In this paper, the effects of different quenched-tempered heat treatment processes on the microstructure and mechanical properties of 30CrMoA round steel for sucker rod are studied. The strength and toughness of the material are improved by adjusting the quenching and tempering temperatures as well as optimizing heat treatment process aiming at the actual application requirements of 30CrMoA steel. The experimental results showed that the yield strength, tensile strength, yield ratio and impact energy of the material could be significantly improved with proper quenching and tempering, especially under the conditions of 850 ℃ quenching(water cooling) +540 ℃ tempering (water cooling), the comprehensive mechanical properties of round steel 30CrMoA for sucker rod were the best, which was with good strength and toughness. The metallographic analysis showed that the quenched and tempered microstructure was mainly composed of tempered sorbite, which was with stable microstructure.

The hot rolled coil plate for pipeline steel is mainly used for manufacturing delivery welded pipe of petroleum and natural gas. In this paper, the development of hot rolled coil plate for L485M pipeline steel with heavy gauge and low costs is introduced. The design with diversified alloy systems of C-Mn-Cr-Mo or C-Mn-Cr-Mo-Ni as well as smelting of clean steel and thermo mechanical control process (TMCP) are adopted. The microstructure of developed L485M hot rolled coil plate is acicular ferrite+granular bainite and precipitate is homogeneous. The L485M hot rolled coil plate is with such characteristics as high strength and excellent low temperature toughness through such mechanisms as dislocation strengthening and precipitation strengthening. The experimental results showed that the L485M hot rolled coil plates with and without Ni element could meet the technical requirements as well as was with capacity of batch production, which is beneficial for enterprises to reduce costs and increase benefits.

In this article, the low temperature performances of 60 kg/m as-hot-rolled U71Mn and U75V rails as well as U71MnH and U75VH rails after on-line heat treatment produced by Baotou Steel are studied. The relation between the toughness and temperature of different rails in low temperature environment is studied through impact test and test for fracture toughness of rails in the low temperature environment created in the laboratory. It is elaborated the performance indexes of safe service for rails of Baotou Steel in low temperature environment and summarized the relations of toughness indexes for four types of rail products of Baotou Steel in low temperature environment, which provide the data support for selecting rails in plateau and low temperature regions as well as safe operations of railway system in extremely cold environment.

With the development of digital and intelligent technologies in each field, they are widely applied due to the high efficiency and accuracy they brought. The digital and intelligent technologies for detection and routing inspection of industrial buildings (structures) are increasingly developed. In this paper, the important roles of intelligent detection technologies in safe operations of structure for industrial buildings (structures) are compared and explained through the specific analysis on applications of such three common intelligent detection technologies in detection of industrial buildings (structures) as unmanned aerial vehicle platform technology, digital image recognition technology and network technology of intelligent sensor for Internet of things.

The effects of double calcium treatment mode (Ca treatment-RH-Ca treatment) and single calcium treatment mode (RH-Ca treatment) on removing inclusions are studied with the process route of BOF-LF-RH-CC. The study results showed that the size and number of inclusions in molten steel with single calcium treatment mode when RH left were smaller than those with double calcium treatment mode so that single calcium treatment mode was better than double calcium treatment mode.

In the paper, the chromite as well as external phlogopite and ferrodolomite are analyzed with such means as the point analysis with EPMA(electron probe micro-analyzer), map scanning and correlation analysis from the perspective of geochemistry. It is found from the analysis results that three annuluses can be seen inside and out of chromite, the contents of Al, Mn and Zn in the center are higher than those in outer ring as well as content of Fe in outermost ring is high, that is, the contents of Mn, Al and Zn are gradually decreased as well as content of Fe is gradually increased inside and out of the chromite. This indicates that the magnesium aluminate spinel should be formed firstly in this region, then it is replaced by fluorine-rich magma to chromite in later period, the fluorine-containing and silica-containing magma upwells into carbonatite dykes along channel as well as it is condensed into fluorine-containing phlogopite at the same time. The conclusion consistent with the above could be obtained with the Pearson correlation analysis, that is, there are negative correlations between FeO and Cr₂O₃, MnO, ZnO and Al₂O₃, which shows that there is isomorphic substitution among them.

The methods of manual dynamic regulation of bottom blowing of converter with steel grade of smelting and dynamic maintenance of furnace profile are proposed aiming at such problems as low gas supply intensity of bottom blowing, short service life of breathable element for bottom blowing and lower combined blowing rate for 150 t top bottom combined blowing converter in Steel-making Plant. Different gas supply intensity models are established and gas supply intensity of bottom blowing is optimized based on the requirements for end point carbon content of steel grade in actual production. As a result, the dynamic control of gas supply intensity of bottom blowing for smelting different steel grades is realized, iron oxide content of final slag of converter and end point product of carbon concentration and oxygen concentration are effectively reduced as well as metallurgical effects of bottom blowing system and quality of molten steel are improved.