湖南华菱湘潭钢铁有限公司

To develop high-temperature wear resistant steel with high tempering stability that can be used in high temperature environments， the bond energy between different alloying elements and C element is calculated by solid and molecular empirical electron theory， and a series of TiC particle-reinforced high-temperature wear-resistant steel components are designed. The precipitation temperature of TiC particles is calculated by Thermo-Calc software and the tempering stability of the steel plate after the best heat treatment is tested at different temperatures and time. The results show that the bond energy formed by Cr， Mo， and W with C is significantly higher than that of Fe—C. Therefore， the activation energy of C atom diffusion in martensite increases， which hinders the diffusion of C atom in martensite and improves the tempering resistance of martensite. Therefore， Cr， Mo， and W are determined as the main addition elements to improve the thermal stability of TiC-reinforced martensitic wear-resistant steel. TiC particles precipitate in the temperature range of 1400-1500 ℃， and the particle morphology shows that the particles distribute like grain boundaries. After thermomechanical processing， micron TiC particles can uniformly distribute on the matrix. The experimental results of tempering stability show that the addition of Cr and W elements greatly improves the tempering stability.

In order to reveal the change and reason of microstructure and hardness of antimony micro-alloyed ferrite cryogenic steel during continuous cooling transformation,hot compression tests were conducted on a Gleeble 3800 ther-mal simulator and the dynamic continuous cooling transformation(CCT)curves of the experiment steel were deter-mined based on the experiments.The microstructure and the Vickers hardness at different cooling rates was character-ized by optical microscope and microhardness tester,respectively.The results show that when the cooling speed re-mains at 0.1℃/s,the microscopic organization of experimental steel is composed of polygonal ferrite and beads;when the cooling speed is within 0.3℃-1℃/s,the microstructure appears as polygonal ferrite,pearlosite and granular bainite;When the cooling speed is increased to 3℃/s,-40℃/s,the microstructure appears as polygonal ferrite and plated bainite.Due to fine grain and granular bainite strengthening,the hardness increases rapidly from 172.1HV to 207.7HV when the cooling rate is 0.1℃/s-1℃/s.Due to the refinement of the microstructure and the increase of the proportion of plated bainite,when the cooling rate is 3℃/s-40℃/s,the hardness increases linearly from 214.9 HV to 261.8 HV with the cooling rate.The suitable controlled cooling interval of Sb-alloyed ferritic cryo-genic steel is 3℃/s-40℃/s.

More steel scrap consumption in the iron and steel industry can not only mitigate the shortage of iron ore resources but also greatly lower production costs and carbon emissions to the atmosphere, which is a crucial link in low-carbon metallurgy. Because of the drawbacks of different factors, the amount of steel scrap consumed in the current converter steelmaking process is restricted, and the technology of multipoint adding scrap comes into play. Thus, steel scrap addition into ladles has gradually garnered attention from metallurgical experts, but there are few reports on the three-dimensional melting behavior of steel scrap in a real ladle environment with argon blowing. To examine the melting law of steel scrap in a ladle, in this study, the flow field, temperature distribution, and melting behavior of steel scrap in a 70 t refining ladle at various argon blowing rates with steel scrap addition of different specific surface areas and preheating temperatures were numerically investigated and compared using a mutiphysical mathematical model. The results revealed that the melting rate of steel scrap increases with increasing specific surface area, and bottom argon blowing can accelerate the melting of steel scrap, while the promoting effect gradually decreases with increasing specific area. With bottom argon blowing, the core temperature of steel scrap with specific surface areas of 120, 130.22, and 160.81 m2·m-3 increased by 7.06, 6.51, and 3.73 K·s-1, the melting rate was increased by 0.92, 0.88, and 0.28 cm3·s-1, and the melting time was shortened by 17, 15, and 3 s, respectively, compared with those without bottom blowing. When the initial temperature of steel scrap increases from 300 to 1000 K, the melting rate increases from 2.97 to 3.26 cm2·s-1 and the melting time is shortened by 3 s accordingly. The argon blowing rate significantly influenced the melting rate of steel scrap. When the argon blowing rate increases from 100 to 200 L·min-1, the melting time of steel scrap with specific surface areas of 120, 130.22, and 160.81 m2·m-3 is reduced from 44 to 35 s, 42 to 34 s, and 34 s to 31 s, respectively. Thus, on the premise of smooth production, the melting speed of the steel scrap in the ladle can be significantly increased by increasing the argon blowing rate and adding the slab scrap at higher initial temperatures and specific surface areas. This work offers a reference for developing steel scrap rapid-melting technology for ladles in steel plants.

As an important means of cargo transport in steel enterprises,railway transport currently encounters challenges,such as complex operational environments,high on-site operational intensity,elevated safety risks,and low levels of automation.To address these issues,this paper proposes a locomotive automatic transport system that integrates various technologies,such as automatic operation,obstacle detection,fusion positioning,and 5G communication.This solution is designed with a focus on the railway transport requirements of automation,intelligence and flexible manpower line,taking into account specific operational scenarios in steel mills and the principles of train control systems in rail transit.Key technical aspects,such as control modes and obstacle perception,are discussed in further detail.In subsequent implementation within a steel mill,the proposed system enabled multiple functions,including intelligent dispatching,intelligent environmental perception,automatic coupling of running locomotives,stopping with a precision of±20 cm,and detection of obstacles(larger than 0.3 mm×0.3 mm×0.3 mm)at distances ranging from 20 m to 150 m ahead with both error and omission rates lower than 3%.This solution also effectively reduced labor intensity and safety risks for operators,and achieving automatic and intelligent railway transport operations within this steel mill.

For the corrosion problem within the reclaimed water transport pipelines of a steel company in Hunan,water samples from typical reclaimed water sources were collected for water quality analysis.The corrosion behavior of the reclaimed water transport pipelines was systemat-ically investigated through hanging plate tests,microbial culture counting,electrochemical testing,scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD).Moreover,the corrosion inhibitory effects of hydroxyethylidene diphos-phonic acid(HEDP),2-Phosphonobutane-1,2,4-Tricarboxylic Acid(PBTCA)and polyaspartic acid(PASP)were examined.Results showed that the quality of reclaimed water was significantly impacted by biological dephenolization wastewater,blast furnace drainage,total drainage in the direction of five meters and drainage from three water stations.The passivation film on the surface of reclaimed water pipelines was destroyed by the action of Cl-and SO42- in the water,while iron bacteria and sulfate-reducing bacteria promoted corrosion,resulting in the formation of Fe(OH)3 and FeS.After the addition of HEDP and PBTCA corrosion inhibitors,a decrease in the thickness of the corrosion layer was observed,and the corrosion rate fell below the national standard.Following the addition of PASP,the corrosion products on the surface of the hanging plate were loose and porous siderite.In the low-frequency impedance region,Warburg impedance characteristics were displayed,and the corrosion inhibition rate was only 3.9％.