Shape-Memory Materials

I: Phenomena in the Blast Furnace.- 1 Dissection of Quenched Blast Furnaces.- 1.1 Introduction.- 1.1.1 Background to the present study.- 1.1.2 Methods of quenching and their effects.- 1.1.3 General in-furnace situations and peculiar phenomena.- 1.2 Relation Between Behavior of Descending Burden and State of Combustion Zone.- 1.2.1 Fundamental descent behavior of burden in the shaft.- 1.2.2 Asymmetrical descent of burden.- 1.3 Behavior of the Core.- 1.4 Situations in and Around the Combustion Zone.- 1.4.1 State in front of the tuyere nose.- 1.4.2 Formation of shell and movements at the lower part of the raceway.- 1.4.3 Conditions inside the furnace and the shape of the raceway.- 1.5 Shape of Cohesion Zone and Relation to Distribution and Movement of Burden.- 1.5.1 Formation of the cohesion zone.- 1.5.2 Relation between shape of the cohesion zone and operation conditions.- 1.6 Behavior of Circulating Elements.- 1.6.1 Effect of water quenching on the circulating elements.- 1.6.2 Behavior of circulating elements and amounts of circulation.- 1.7 Changes in Properties of Burden Materials.- 1.7.1 Macroscopic changes.- 1.7.2 Microscopic structural and composition changes.- 1.7.3 Effects of circulating elements on the behavior of the cohesion zone.- 1.8 Reactions in the Hearth.- 1.8.1 Slag formation reactions.- 1.8.2 Changes in the metal composition.- 1.9 Concluding Remarks.- 1.10 Addendum.- 1.10.1 Arrangement inside the furnace.- 1.10.2 Changes in properties of the burden.- 2 Measurements in Operating Blast Furnaces.- 2.1 Objectives of Blast Furnace Measurements.- 2.2 Development of Measurements for Clarification of Furnace Reactions.- 2.2.1 Standard instrumentation for blast furnaces a decade ago.- 2.2.2 Development of instrumentation since the introduction of blast furnace dissection.- 2.3 Relationship Between Furnace Measurement and Furnace Operation (Actual Examples).- 2.3.1 Relationship between measurements before blowing out of blast furnace and results of dissection.- 2.3.2 Measurements and estimations of the cohesive zone.- 2.3.3 Development and use of the latest sensors to study furnace interiors.- 2.4 Future Development of Blast Furnace Measurements.- II: Modelling of the Blast Furnace.- 3 Global Formulation.- 3.1 Review of Blast Furnace Models.- 3.1.1 Reichardt diagram.- 3.1.2 Operation diagram.- 3.1.3 Kinetic model.- 3.1.4 Control models.- 3.1.5 Models for estimating internal situations based on observed data.- 3.2 One-dimensional Static Model.- 3.2.1 Overall reaction rates.- 3.2.2 Overall material balance.- 3.2.3 Temperatures of gas and solid at the top of the furnace.- 3.2.4 Flow rate and composition of gas at tuyere level.- 3.2.5 Theoretical flame temperature.- 3.2.6 Temperature of gas and coke at tuyere level.- 3.2.7 One-dimensional mathematical formulation for internal state of blast furnace.- 3.2.8 Effect of various operating conditions on productivity and situation in blast furnace.- 3.2.9 Some applications of the model.- 3.3 Layered Structure Model.- 3.3.1 Radial distribution of flow rate of gas.- 3.3.2 Mathematical-kinetic model of blast furnace.- 3.3.3 Numerical analysis of blast furnace operation.- 3.3.4 Computed results.- 3.3.5 Steady-state two-dimensional modelling.- 3.3.6 Governing equations for cylindrical polar coordinates.- 3.3.7 Some auxiliary relations.- 3.3.8 Numerical solution of two-dimensional model.- 3.4 Two-dimensional Model for Gas Flow, Heat Transfer and Chemical Reactions.- 3.4.1 General concept of the radial distribution model.- 3.4.2 Momentum transfer.- 3.4.3 Mass transfer with chemical reactions.- 3.4.4 Heat transfer.- 3.4.5 Input conditions.- 3.4.6 Method of analysis.- 3.4.7 Simulation results.- 3.5 Two-dimensional Formulation by Finite Element Method.- 3.5.1 Flow analysis of gas.- 3.5.2 Computed results for gas flow.- 3.5.3 Simultaneous analysis of gas flow and heat transfer.- 3.5.4 Computed results on the simultaneous gas flow and heat transfer.- 3.6 Model for Estimating the Profile of the Cohesive Zone.- 3.6.1 General description of the mathematical model.- 3.6.2 Relation between indices estimated using the mathematical model and from blast furnace operation (cohesive zone analysis with 4000 m3 class blast furnace).- 3.6.3 Analysis of operation with decrease in production.- 3.6.4 Future direction.- 3.7 One-dimensional Dynamic Model.- 3.7.1 Outline of mathematical simulation model.- 3.7.2 Applications to blast furnace operations.- 3.8 Notation.- 4 Flow of Gas, Liquid and Solid.- 4.1 Flow of Solids During Charging and Control of Burden Distribution.- 4.1.1 Burden distribution of bell top furnaces.- 4.1.2 Burden distribution of bell-less top furnaces.- 4.2 Flow of Solids in the Upper Part of the Furnace.- 4.2.1 Information from dissected blast furnaces.- 4.2.2 Burden descent model.- 4.2.3 Decrease in angle of layer inclination with burden descent.- 4.2.4 Influence of some other factors.- 4.3 Flow of Solids in the Lower Part of the Furnace.- 4.3.1 Basic phenomena.- 4.3.2 Formation of mixed zone in the peripheral region near the wall.- 4.3.3 Movement of coke to the raceway.- 4.3.4 Movement of coke in dead coke zone and hearth.- 4.4 Theoretical Approach to the Flow of Burden Material in the Furnace.- 4.4.1 Stress distribution in the blast furnace.- 4.4.2 Inclination of the dead coke zone boundary.- 4.4.3 Notation (Sections 4.3 and 4.4).- 4.5 Numerical Simulation of Radial Gas Flow Distribution.- 4.5.1 Burden distribution model.- 4.5.2 Two-dimensional gas flow in the blast furnace.- 4.5.3 Outline of results of calculation.- 4.5.4 Concluding remarks.- 4.5.5 Notation.- 4.6 Flow of Gas and Liquid in the Dropping Zone.- 4.6.1 Counter-current flow region.- 4.6.2 Cross flow region.- 4.6.3 Concluding remarks.- 4.7 Flow of Slag and Metal in the Hearth During Tapping.- 4.7.1 State of coke bed in the hearth.- 4.7.2 Flow of slag during tapping.- 4.7.3 Flow of metal during tapping.- 4.7.4 Mathematical simulation of hearth flow.- 4.7.5 Concluding remarks.- 5 High Temperature Properties of Iron Ore Agglomerates.- 5.1 Reduction Behavior in Lumpy Zone.- 5.1.1 Estimation of reducibility in lumpy zone.- 5.1.2 Determination of reaction rate constant of reduction and comparison with blast furnace operation.- 5.2 Change of Mineral Phases in Blast Furnace.- 5.2.1 Change of mineral phases during reduction.- 5.2.2 Mineral phases in reduced iron ore agglomerates.- 5.2.3 Change of gangue minerals.- 5.3 Flow Resistance of Gas Through the Fused Packed Bed.- 5.3.1 Measurement of pressure drop in fused packed bed.- 5.3.2 Numerical calculation of gas flow resistance through a fused packed bed by use of an orifice model.- 5.3.3 Equation of pressure drop in fused packed bed.- 5.3.4 Quantitative determination of softening properties.- 5.4 Effects of High Temperature Properties of Burden on Blast Furnace Operation.- 5.4.1 Factors for evaluating high temperature properties of burden.- 5.4.2 Relationship between high temperature properties of burden and blast furnace operating performance.- 5.5 High Temperature Properties of Burden with Cohesive Zone Model and Direct Measurement of Cohesive Zone.- 5.5.1 Estimation of cohesive zone with theoretical models.- 5.5.2 Effect of softening properties on gas permeability.- 5.5.3 Evaluation of softening properties of sinter.- 5.5.4 Direct measurement of cohesive zone.- 5.6 Notation.- 6 The Raceway.- 6.1 Measurement and Observation of the Blast Furnace Raceway.- 6.1.1 Movement of coke particles in the raceway.- 6.1.2 Condition near the raceway.- 6.1.3 Reactions in the raceway.- 6.2 Mathematical Model of the Raceway.- 6.2.1 One-dimensional model.- 6.2.2 Two-dimensional model.- 6.3 Notation.- 7 The Lower Region of the Blast Furnace and the Slag-Metal-Gas Reaction.- 7.1 Reaction of Silicon.- 7.1.1 Introduction.- 7.1.2 Behavior of silicon in the blast furnace.- 7.1.3 Kinetics of silicon transfer.- 7.2 Other Reactions.- 7.2.1 Manganese.- 7.2.2 Titanium.- 7.3 Application of Reaction Models of Silicon to Blast Furnace Operation.- 7.3.1 Review of silicon reaction models.- 7.3.2 Partition reactions of Si, S and Mn.- 7.3.3 Mathematical model of silicon reactions in the blast furnace.- 7.4 Notation.- III: Flexibility and Adaptability of Blast Furnace.- 8 Blast Furnace Ironmaking Technology in the Near Future.- 8.1 Flexible Operation.- 8.2 Increase of Furnace Life.- 8.3 Mechanization of Cast-house Operation.- 8.4 Technology Development Related to Innovative Steelmaking Process.- 8.5 Use of Blast Furnace for Producing Other Metals.

Blast furnace phenomena and modelling

Thermal stability and some thermodynamics analysis of heat treated quaternary CuAlNiTa shape memory alloy

To offer a response to the increasing interest on high-temperature shape memory alloys, mainly driven by the aeronautic and aerospace industries, the design and characterization of Cu-Al-Ni shape memory alloys with high transformation temperatures, between 373 K and 473 K, are approached. The present alloy design is based on the transformation from cubic β3 austenite to the monoclinic β'3 martensite, which offers the advantage of exhibiting not only higher transformation temperatures but also a thermal hysteresis of about 12 K, much smaller than the orthorhombic γ'3 martensite historically considered for this alloy system. The influence of the alloy concentration and the thermal treatments, on the martensitic transformation temperatures is systematically analyzed and a quantitative and predictive equation is proposed. The influence of the stress on the transformation was also studied under two experimental conditions: at constant stress as a function of temperature (shape memory effect) and at constant temperature as a function of the stress (superelastic effect). A double stress-induced transformation from β3 to β'3 and α'3 with an outstanding reversible and reproducible 24% superelastic strain is also reported. The experimental results allows also determine the Clausius-Clapeyron diagrams for this series of alloys, as a fundamental tool for further design of sensing and actuating devices based on these high-temperature shape memory alloys.

High-temperature shape memory alloys based on the Cu-Al-Ni system: design and thermomechanical characterization

Cu-Al-Ni shape memory alloys (SMAs) have been developed for hightemperature applications due to their ability to return to pre-deformed shape after heating above the transformation temperature, as well as these alloys have a small hysteresis and high transformation temperature comparing with other shape memory alloys. Adding some of the alloying elements such as Ti, Mn, Be, Zr and B or changing the interior content either Al or Ni by increasing/decreasing may have a significant effect on the phase transitions and enhance the mechanical properties of these alloys. However, the martensite phase transformation is the most important factor, which can be changing the whole properties of Cu-Al-Ni SMAs, where this phase is mainly affected by the alloying elements additions. This chapter reviews the effect of alloying elements on the phase transitions and the enhancement of the mechanical properties of this alloy.

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Cu-Based Shape Memory Alloys: Modified Structures and Their Related Properties

Methods of fabricating Cu-Al-Ni shape memory alloys

A stable and efficient blast furnace operation requires proper control of hot metal and slag drainage from the hearth. Many operational problems such as non-dry casts, blow outs, excessive hearth lining wear and low-blast intake arise when the liquid level in the hearth exceeds the critical limit where hearth coke and deadman start to float. Since the direct measurement of the hearth liquid level is practically impossible due to high temperature and pressure inside the furnace, it is therefore important to estimate the liquid level in the hearth and display it to the operators on real-time basis for efficient cast management. This paper presents a system, called hearth liquid level monitoring (LLM), which simulates the liquid level and drainage behaviour of the furnace hearth. It is based on the theoretical hot metal and slag generation rate from the specific oxygen rate and the computed drainage rate from torpedo radar signals and the slag flow measurement system. The system advises the blast furnace ope...

Real-time blast furnace hearth liquid level monitoring system

The determination of thermal condition of the blast furnace is necessary for various reasons, such as to facilitate the operation, maintain a stable furnace condition, predict heat or heat tendency of the furnace and predict hot metal temperature (HMT). It can become a tool for controlling the product quality of the blast furnace. This paper presents a mathematical model for estimating the thermal tendency of the blast furnace. The thermal condition of the blast furnace is represented as thermal energy index, wherein a high thermal energy index denotes heating up of furnace, while a low thermal energy index indicates chilling down of furnace. Using this model, one could hypothetically estimate the thermal condition of the blast furnace in real time. Thereby, corrective controllable actions can be taken on real time to attain the desired HMT before the arrival of actual hot metal analysis.

A mathematical model to control thermal stability of blast furnace using proactive thermal indicator

The key to excellent casthouse operation are low cost, high productivity, dry hearth and high casting rate while minimising the consumable material. The stable blast furnace operation requires prop...

Improvement in casting practice by controlling the drainage rate and hearth liquid level to develop an efficient casthouse management practice in blast furnace

The present work describes the preparation of near-full density Cu–Al–Ni shape memory alloy (SMA) strips via a novel processing route consisting of ‘spray deposition’ of atomised liquid Cu–Al–Ni al

Ashish Agrawal

Papers

Methods of fabricating Cu-Al-Ni shape memory alloys

Real-time blast furnace hearth liquid level monitoring system

A mathematical model to control thermal stability of blast furnace using proactive thermal indicator

Improvement in casting practice by controlling the drainage rate and hearth liquid level to develop an efficient casthouse management practice in blast furnace

Preparation of Cu–Al–Ni shape memory alloy strips by spray deposition-hot rolling route