Ballistic performance of titanium-based layered composites made using blended elemental powder metallurgy and hot isostatic pressing

Metal matrix composites tiles based on Ti-6Al-4V(Ti64)alloy,reinforced with 10,20,and 40(vol%)of either TiC or TiB particles were made using press-and-sinter blended elemental powder metallurgy(BEPM)and then bonded together into 3-layer laminated plates using hot isostatic pressing(HIP).The laminates were ballistically tested and demonstrated superior performance.The microstructure and properties of the laminates were analyzed to determine the effect of the BEPM and HIP processing on the ballistic properties of the layered plates.The effect of porosity in sintered composites on further diffusion bonding of the plates during HIP is analyzed to understand the bonding features at the interfaces between different adjacent layers in the laminate.Exceptional ballistic performance of fabricated structures was explained by a significant reduction in the residual porosity of the BEPM products by their additional processing using HIP,which provides an unprecedented increase in the hardness of the layered composites.It is argued that the combination of the used two technologies,BEPM and HIP is principally complimentary for the materials in question with the abilities to solve the essential problems of each used individually.

Potential of Applying Artificial Intelligence to Hot Metal Logistics Management

The steel industry,known for its complexity and the need to reduce CO_(2)emissions,is adopting advanced digitalization tools to move towards a more sustainable,integrated,and agile operating model.Digital twins with artificial intelligence-based optimization and scheduling models can improve decision-making in logistics,refractory maintenance,and energy efficiency.By incorporating advanced AI algorithms into this decision support system,the hot metal route scenarios can be evaluated,resulting in minimized hot metal temperature losses and increased scrap utilization.This paper integrated digital twins with reinforcement learning algorithms to investigate the logistics of torpedoes and hot metal ladles.It considered important input parameters such as the ladles and torpedoes'thermal state and location,refractory thickness,hot metal volume and temperature,and crane availability.By incorporating advanced AI algorithms into this decision support system,energy-efficient scenarios can be evaluated,increasing scrap utilization and resulting in a possible reduction of 15°C in hot metal temperature losses.

Intelligent optimization method for the dynamic scheduling of hot metal ladles of one-ladle technology on ironmaking and steelmaking interface in steel plants

The one-ladle technology requires an efficient ironmaking and steelmaking interface. The scheduling of the hot metal ladle in the steel plant determines the overall operational efficiency of the interface. Considering the strong uncertainties of real-world production environments, this work studies the dynamic scheduling problem of hot metal ladles and develops a data-driven three-layer approach to solve this problem. A dynamic scheduling optimization model of the hot metal ladle operation with a minimum average turnover time as the optimization objective is also constructed. Furthermore, the intelligent perception of industrial scenes and autonomous identification of disturbances, adaptive configuration of dynamic scheduling strategies, and real-time adjustment of schedules can be realized. The upper layer generates a demand-oriented prescheduling scheme for hot metal ladles. The middle layer adaptively adjusts this scheme to obtain an executable schedule according to the actual supply–demand relationship. In the lower layer, three types of dynamic scheduling strategies are designed according to the characteristics of the dynamic disturbance in the model:real-time flexible fine-tuning, local machine adjustment, and global rescheduling. Case test using 24 h production data on a certain day during the system operation of a steel plant shows that the method and system can effectively reduce the fluctuation and operation time of the hot metal ladle and improve the stability of the ironmaking and steelmaking interface production rhythm. The data-driven dynamic scheduling strategy is feasible and effective, and the proposed method can improve the operation efficiency of hot metal ladles.

Design,preparation,microstructure and mechanical property of the lightweight radiation-shielding Mg-Ta-Al composites basing differential temperature hot rolling

A novel lightweight,radiation-shielding Mg-Ta-Al layered metal-matrix composite(LMC)was successful designed by doping the extremely refractory metal(Ta)into Mg sheets.These Mg-based LMCs sheets shows excellent radiation-dose shield effect,about 145 krad·a^(−1),which is about 17 times of traditional Mg alloy,while its surface density is only about 0.9 g·cm^(−2),reducing by 60%than that of pure Ta.The quantitate relationship between radiation-dose and the materials’thickness was also confirmed to the logistic function when the surface density is in the range of 0.6-1.5 g·cm^(−2).Meantime,the rolling parameters,interface microstructure and mechanical properties in both as-rolled and annealing treated samples were evaluated.The sheets possess a special dissimilar atoms diffusion transitional zone containing an obvious inter-diffusion Mg-Al interface and the unique micro-corrugated Ta-Al interface,as well as a thin Al film with a thickness of about 10μm.The special zone could reduce the stress concentration and enhance the strength of Mg-Ta-Al LMCs.The interface bonding strength reaches up to 54-76 MPa.The ultimate tensile strength(UTS)and yield strength(TYS)of the Mg-Ta-Al sheet were high to 413 MPa and 263 MPa,respectively,along with an elongation of 5.8%.The molecular dynamics(MD)analysis results show that the two interfaces exhibit different formation mechanism,the Mg-Al interface primarily depended on Mg/Al atoms diffusion basing point defects movement,while the Ta-Al interface with a micro-interlock pining shape formed by close-packed planes slipping during high temperature strain-induced deformation process.

Review on hot spinning for difficult-to-deform lightweight metals

Hot spinning process has attracted significant attention because it can be used to manufacture complex parts, extend the forming limit of materials, decrease forming forces and reduce process chains. In this paper, we review researches on lightweight metals spun at elevated temperatures since they are difficult to deform at room temperature. These metals include light alloys, such as titanium, magnesium and aluminum alloys, and metal composites. Then, the heating methods used in the hot spinning process and the treatment methods employed for the temperature boundary condition in finite element analyses for the process were discussed. Finally, the future development directions for the hot spinning process of lightweight but difficult-to-deform alloys were highlighted.

High Efficient Technology of Steelmaking With Low Silicon Hot Metal on Large Converter

To resolve the difficulty in slag formation during steelmaking with low silicon hot metal and to increase productivity, a new 5-hole lance was developed by increasing oxygen flow from 50 000 m^3/h to 60 000 m^3/h. Synthetic slag was added to adjust the slag composition. The problems such as difficulty in dephosphorization and slag adhesion to oxygen lance and hood were settled. Steel production and metal yield were increased and the nozzle life was prolonged through these techniques.

Chaotic Identification and Prediction of Silicon Content in Hot Metal

The time series data of silicon content in hot metal were identified to have the chaotic feature because of the positive maximum Lyapunov exponent, and then the time scales to predict future were estimated. Finally a chaotic local-region model was constructed to predict silicon content in hot metal with good performance due to high hitting rate.

Porous bulk metallic glass fabricated by powder hot pressing

A synthesis method for the production of porous bulk metallic glass (BMG) was introduced. This method utilizes the su- perplastic forming ability of amorphous powder in the supercooled liquid (SCL) state and intenerating salt mixture as a placeholder to produce BMG foam by using a hot die pressing method. Scanning electron microscope (SEM), X-ray diffraction (XRD) and dif- ferential scanning calorimetry (DSC) were employed to characterize the morphologies of foaming structure, the crystallization and the percentage of crystallization of the as-produced porous BMG. The results suggested that the formation of porous structure by su- perplastic forming process is feasible. Good bonding effect was observed between amorphous powder particles. Less than 6.5% of crystalline phases were formed during hot pressing, and less than 5.5% of residual salt was enclosed in the foam. To remove any re- sidual salt particles, salt preforms with three-dimensional network and good connectivity is necessary.

Fuzzy Prediction of Silicon Content for BF Hot Metal

Some key operation variables influencing hot metal silicon content were selected, and time lag of each of them was obtained. A standardized fuzzy system model was developed to approach the random nonlinear dynamic system of the change of silicon content, forecast the change of silicon content and calculate silicon content. The prediction of hot metal silicon content is very successful with the data collected online from BF No. 1 at Laiwu Iron and Steel Group Co.

Simulation and prediction of microstructure in hot forming of metals

The evolution of microstructure seriously influences the forming processes and the quality of forgings in metal hot forming processes, it is therefore desirable to gain information on the microstructure evolution of a process by means of computer simulation, not by conventional trial and error method that is time consuming, expensive and does not always lead to optimum results. Models for microstructural simulation and prediction were set up according to the evolution of microstructure during hot forming and cooling processes. The expanding extrusion complex hot forming and cooling processes, as an example, were simulated.

Vacuum Treatment for Simultaneous Desulphurization and Dephosphorization of Hot Metal and Molten Steel

The vacuum treatment for simultaneous desulphurization and dephosphorization of hot metal and molten steel with pre-melted CaO-based slag was carried out.For pre-treatment of hot metal,both desulphurization and dephosphorization are improved with the increase of CaO in slag,but deteriorated with the increase of CaF2 in slag.The average desulphurization and dephosphorization rate is 68.83 % and 78.46 %,respectively.For molten steel,the substitution of BaO for CaO in slag has minor effect on simultaneous desulphurization and dephosphorization.The desulphurization and dephosphorization rate is higher than 90% and 50% respectively with the lowest final sulfur and phosphorus mass percent being 0.001 2% and 0.010%,respectively.The overall effect of simultaneous desulphurization and dephosphorization of molten steel is better than that of hot metal.

Investigation on Steelmaking with Hot Metal Containing Low Silicon Content in Large Converter

There are some problems in steelmaking with hot metal containing low silicon content such as difficulty in slag formation, less slag for dephosphorization and slag adhesion on oxygen lance and hood. To overcome these problems, experiments wcrc conducted and some improvements were obtained, such as adding appropriate flux, increasing the lance position slightly during steelmaking and using effective multi-outlet nozzle. Moreover, to keep normal heating rate, the ore and scrap charge should be reduced due to less chemical heat input in steelmaking.

Kinetic Factors for Intensive Reaction of Magnesium-Based Spheroidiser in Hot Metal

The spheroidiser is a necessary additive to manufacture ductile iron.Sometimes with the same hot metal,spheroidisers and treated technology,reactions differ greatly from each other.The reaction may be quite normal in one case,but very intensive for another one.The effects of kinetic factors such as size,surface area and morphology o f spheroidiser on the reaction of spheoidization are studied.

Effect of deformation temperature on the hot compressive behavior of metal matrix composites with misaligned whiskers

A multi-inclusion cell model is used to investigate the effect of deformation temperature and whisker rotation on the hot compressive behavior of metal matrix composites with misaligned whiskers. Numerical results show that deformation temperature influences the work-hardening behavior of the matrix and the rotation behavior of the whiskers. With increasing temperature, the work hardening rate of the matrix decreases, but the whisker rotation angle increases. Both whisker rotation and the increase of deformation temperature can induce reductions in the load supported by whisker and the load transferred from matrix to whisker. Additionally, it is found that during large strain deformation at higher temperatures, the enhancing of deformation temperature can reduce the effect of whisker rotation. Meanwhile, the stress-strain behavior of the composite is rather sensitive to deformation temperature. At a relatively lower temperature （150℃）, the composite exhibits work hardening due to the matrix work hardening, but at relatively higher temperatures （300℃ and above）, the composite shows strain softening due to whisker rotation. It is also found that during hot compression at higher temperatures, the softening rate of the composite decreases with increasing temperature. The predicted stress-strain behavior of the composite is approximately in agreement with the experimental results.

Prospect of Refractory for Hot Metal Pretreatment

The paper describes the recent developing situation and the latest research achievements of refractory for hot metal pretreatment. The relationship among desiliconization, dephosphorization and desulphurization techniques and the main corrosion reactions by various treating agents is analyzed. Some improving measures for several problems in practice are put forward while we anticipate the future developing direction of refractory for hot metal pretreatment.

Thermodynamic Study on BaO－BaF_2－Fe_xO Slags Used for Dephosphorization of Chromium－Containing Hot Metal

Electrochemical measurements of the solid-oxide galvanic cell, Mo|Mo+MoO2|ZrO2 (MgO)| Fe+ (FexO)+Ag| Fe, have been made at temperatures of 1473K and 1573K in order to obtain the activities of FexO in BaO-BaF2-FexO slags used for dephosphorization of chromium-containing hot metal. The FexO activities show a significant dependence upon the molar ratio of BaO/BaF2. Within the homogeneous liquid region, the substitution of BaF2 for BaO has an effect of raising the FexO activity. From these activity data, the phase diagrams of the system BaO -BaF2-FexO are drawn at 1473K and 1573K. The temperature dependence of the activity coefficient of FexO at a fixed BaO/ BaF2 molar ratio can be expressed by formula RTlnγ(FexO)=constant.

Hot macro-hardness of Zr52.5Al10Ni10Cu15Be12.5 bulk metallic glass

The hot hardness behavior of Zr52.5Al10Ni10Cu15Be12.5 bulk metallic glass is studied from ambient temperature to the temperature over Tx （the onset crystallization temperature） using a hot macro-hardness tester and scanning electron microscopy （SEM）. The results show that the hot hardness behavior of Zr52.5Al10Ni10Cu15Be12.5 bulk metallic glass can be classified into 4 zones： the glassy zone in which the hardness almost linearly decreases with the increase of temperature, the viscoelastic zone in which the hardness is nearly unchanged, the viscous flow zone in which the hardness quickly tends towards near zero with temperature, and the crystallization zone in which the hardness sharply increases. The high temperature deformation behavior and the easy processable deformation region for bulk metallic glasses are also discussed on the basis of the hot marco-hardness.

Eco-Friendly Smokeless Al_2O_3-SiC-C Brick for Hot Metal Ladle

Hot metal transfer ladles were historically lined with high alumina refractories because of compatibility of high alumina refractories with the highly acidic slag, which is transferred .from the iron making plant along with hot metal. With the introduction of higher capacity ladles, technological advancement in the process and increased productivity, calls for a higher campaign life of hot metal ladles, which could not be performed by ordinary high alumina refractories. Resin bonded Al2O3- SiC-C （hereinafter ASC ） bricks gradually developed which at present taking place replacing the conventional refractories. Considerable work has been carried out in developing the ASC refractory to reach the present state. However, for higher capacity ladles still there is a lot of scope for improvement. The present paper deals with the newly developed ASC bricks, which was used in 165 ton capacity hot metal ladles in one European plant and has given a substantial increase in performance. But, the customer was not fuUy satisfied since the brick was reported to produce smokes during preheating of the ladle. In the subsequent supply the smoke generation problem was taken care by adjusting the binders and additives and eco-friendly bricks were re-engineered and supplied to the same plant, which also performed splendidly and created all time record in their plant history.

Technical and economic analysis of Ni-containing hot metal production with laterite in blast furnaces

In recent years, many Ni-containing materials manufactured from laterite have played a significant role in supporting the rapid development of the stainless steel industry in China. Currently ,pyrometallurgy is the main process for laterite smelting, where blast furnaces are employed to make Ni-containing hot metal. With the aim of giving some references for making good use of laterite, technical and economic analysis was conducted in this paper, based on the discussion of the key technologies of Ni-containing hot metal production with laterite （50.4% Fe） in blast furnaces.

The hot compressive deformation behavior of the metal matrix composites with the large whisker orientation

Finite element analysis was used to investigate the effects of whisker misalignment on the hot compressive deformation behavior of whisker-reinforced composites. The simulation provided the evolution of the stress field of the composites and the whisker rotation process. It is found that with increasing the angle of whisker misalignment the whisker rotation angle decreases. Meanwhile, the mechanical behaviors of the composites such as work hardening or strain softening are affected by the whisker orientation and rotation during the hot compressive deformation. The predicted results are in agreement with the experimental results.