bluuebunny/crossref_metadata_2025 huggingface dataset:
Material Properties of Induction Tempered High Tensile Valve Spring Wire
Authors: Berntsson Tomas , Jarl Magnus
Published: December 2016

Most of today's hardened valve spring wires are tempered in a lead bath. The lead bath provides a stable and accurate degree of tempering of the wire, but it has environmental disadvantages and limitations in flexibility. This paper describes how induction heating can replace lead bath and how this may affect the material properties. The study includes FEM‐simulations, calculation of the tempering parameter and experiments with induction tempering of three different SiCr valve spring steels carried out under pilot production. The mechanical properties of the test samples were measured. Fatigue testing of one of the steels was performed on finished springs. The results were evaluated by comparing induction‐tempered wire with the conventional lead tempered reference wire. The induction tempered wire fulfilled the product requirements and corresponded in performance with the lead tempered wire.
Influence of Non‐linear Effects on Fatigue Assessment of a Welded Structure
Authors: Pettersson Gert
Published: December 2016

In this paper root cracks in a welded structure are investigated using the effective notch stress approach and Linear Elastic Fracture Mechanics (LEFM). The problem is complicated by the fact that the welds subjected to endurance stress are located close to a screw joint. The Finite Element (FE) model used for evaluating the fatigue life includes both this screw joint as well as adjacent components and the contact behaviour between the structures. Several important problems in the evaluation of stress intensity factors and notch stresses are investigated. The results can give useful information in the work of performing a fatigue analysis. The areas examined are the significance of the load direction, mesh density, the importance of the right global stiffness in the model, the crack deflection angle and the modelling of a root notch versus the requirements on the drawing.
Fatigue Life Estimation of Ultrasonic Impact Treated Welds Using a Local Strain Approach
Authors: Lihavainen Veli‐Matti , Marquis Gary
Published: December 2016

It is commonly observed that complex fabricated structures subject to fatigue loading fail at the welded connections. Some problems can be corrected by improved detail design but fatigue performance can also be improved using post‐weld improvement methods. Ultrasonic impact treatment (UIT) is a relatively new and efficient post‐weld improvement method. The current study presents experimental fatigue strength data of non‐load carrying attachments in the as‐welded and UIT treated condition. Treated welds were found to have about 50% greater fatigue strength. This improvement in strength has been modelled using the local strain approach. Material parameters in the highly cold‐worked UIT treated zone have been derived using the Uniform Material Law for fatigue analysis. The stress concentration was computed using FE analysis and mean stress estimates were based on X‐ray diffraction measurements of the residual stress state in the treated zone. The predicted degree of improvement was in excellent agreement with the experimentally measured improvement.
Improving the Accuracy of Structural Hot‐spot Stress Approach
Authors: Poutiainen Ilkka , Marquis Gary
Published: December 2016

A method for extending the applicability of the structural hot‐spot stress method for fatigue assessment of welded structures is discussed. The structural hot‐spot stress method for plate structures, as currently presented in commonly used design guidance documents, cannot account for the effect of weld size, and load carrying fillet welds are assessed using a different S‐N curve as compared to non‐load carrying fillet welds. This paper presents a proposal to linearize the local stress distribution through the plate thickness in the plane of the weld toe. This proposal considers the forces transmitted by the weld itself. A bilinear stress distribution, which partially captures the local effect of the weld, is derived from the non‐linear stress distribution. The non‐linear distribution is based on equilibrium and the stress in the fillet weld. A simple procedure is presented to determine the bilinear curve from the nominal weld stress. This is a great advantage in finite element analysis when only nominal base plate stress and nominal weld stresses need to be determined. When compared to the more conventional structural stress approach, the new method also has the advantage that extrapolation is not required. The same weld stresses can also be used in the analysis of the root cracks. The proposed method was scaled to correspond to the traditional structural hot‐spot stress method using detailed linear elastic fracture mechanics simulations. The method is only applied to fully load‐carrying welds here but can also be used for partial load‐carrying welds. A symmetric splice plate having a fully loaded fillet weld is presented as an example case. The influence of base plate thickness is studied as well.
Heat Withdrawal in the Mold in Continuous Casting of Steel. Review and Analysis
Authors: Schwerdtfeger Klaus
Published: December 2016

Two principal methods are used to investigate the heat transfer in the continuous casting mold. The direct way is to measure cooling water temperatures, mold wall temperatures, strand temperatures and shell thickness in actual operation, and then deduce from these data the correlations for heat flux densities. The other way is to investigate the “unit operations” of heat transfer theoretically or experimentally in the laboratory, viz. heat transfer through a layer of casting flux or of gas, and heat transfer in a copper wall cooled on one side by water. The results obtained in this approach can then be used to explain the data determined with the direct method and to optimize the heat transfer behaviour of the mold in the machine. In the first part of this paper some unit operations are discussed and engineering formulae are given for computation of the heat resistances of the gap and the copper/water system. In the second part of the paper the available operational data on heat flux density are analysed. Algorithms are presented for computation of local and average heat flux density as functions of casting speed, carbon content of the steel and composition of the casting flux. Finally, values of shell thickness are computed with the correlation for heat flux density and are compared with the measured data.
Numerical Evaluation on Lower Temperature Operation of Blast Furnaces by Charging Carbon Composite Agglomerates
Authors: Chu Mansheng , Yagi Jun‐ichiro , Nogami Hiroshi
Published: December 2016

This paper places emphasis on evaluating ironmaking operation at lower temperature. Blast furnace operation with carbon composite agglomerates (CCB) charging and/or lower operation temperature has been numerically examined using a modified multi‐fluid blast furnace model under constant thermal conditions of the raceway. The numerical calculation shows that a lower in‐furnace temperature level is achieved under the operation with the CCB charging. With CCB charging, the location of the cohesive zone shifts downward and the temperature of the thermal reserve zone decreases. The decrease in heat requirements for solution loss, sinter reduction and silicon transfer reactions compensates the increase in heat demands for CCB reduction and direct reduction, and rather improves the efficiency of blast furnaces. Consequently, the productivity improves, the coke rate shows a notable decrease and the total reducing agent rate also tends to decline compared with conventional operation without CCB charging. Therefore, charging carbon composite agglomerates contributes to the enhancement of blast furnace performance. Furthermore, the model predicts that higher operation efficiency is achieved if the melting and/or tapping temperature could be dropped. The innovative technology of lower temperature ironmaking is expected to be applied in industrial blast furnaces after resolving the problems in engineering and economic evaluations.
An Improved Model for the Longitudinal Peak Strain in the Flange of a Roll Formed U‐Channel developed by FE‐Analyses
Authors: Lindgren Michael
Published: December 2016

Today one can find cold roll forming (CRF) products in many applications, for example vehicles, furniture and in the building industry. Though CRF is a well known sheet metal process, it is still not entirely understood due to the geometrically complex forming. There are several computer aided engineering (CAE) programs on the market that can assist the tool maker when designing a new CRF machine. However, they are often based on simple formulas when predicting the stress and the strain in the strip.

The main objective of this study is to improve formulas for the longitudinal peak membrane strain and the deformation length when a U‐channel is formed. These are important since they can be used to determine the number of forming steps and the distance between them. A two‐level factorial design is done using the finite element analysis to investigate which parameters affect the peak strain and the deformation length. The parameters are then used to build models for the peak strain and the deformation length.
Forming Limit Curve (FLC) and Fracture Mechanism of Newly Developed Low‐Carbon Low‐Silicon TRIP Steel
Authors: Zhang Mei , Li Lin , Su Yu , Fu Renyu , Wan Zi , De Cooman Bruno C.
Published: December 2016

The Forming‐Limited Diagram (FLD) of intercritically annealed 0.11C‐1.65Mn‐0.62Si TRIP‐assisted steel was investigated. The high FLD0 value of this new low carbon TRIP steel was indicative of a superior formability. The micro‐structural changes during deformation and fracture were studied in detail. The polygonal ferrite phase was found to plastically deform first and deformed most at larger strains. Fracture was initiated by micro‐voids nucleated at ferrite grain boundaries, within ferrite grains or at the interface between ferrite and the harder phases. Cracks were formed after micro‐voids grew, coalesced, and expanded in one direction. When crack tips reached the bainite phase or the martensite/austenite constituent, the cracks propagated along the boundary of these phases. Cracks reaching retained austenite islands caused stress‐induced martensite transformation at the crack tip. The direction of motion of the cracks also changed in this case.
A Constitutive Creep Equation for 9Cr‐1Mo‐0.2V (P91‐type) Steel under Constant Load and Constant Stress
Authors: Nagode A. , Ule B. , Jenko M. , Kosec L.
Published: December 2016

The creep behaviour of 9Cr‐1Mo‐0.2V (P91‐type) steel was studied at elevated temperatures of 625 to 675 °C. These temperatures considerably exceed the maximum service temperature of this steel, which is approximately 600 °C. Uniaxial creep tests were performed under constant load and constant stress at initial stresses of 120 to 240 MPa. These tests are considered as short‐term tests and they can even be applied for creep lifetime assessment, albeit with certain limitations. However, the main purpose of this work was to find a constitutive creep law that would satisfactorily describe the creep behaviour of P91‐type steel and enable a comparison of the results obtained with both kinds of creep tests, i.e., under constant load and constant stress.

It is well known that the minimum creep strain rate of P91‐type steel cannot be satisfactorily described by the simple Arrhenius‐type power‐law constitutive model. Therefore, an improved stress‐dependent energy‐barrier model for the description of the creep behaviour of P91 steel was used. The model showed that there is a small difference in the apparent activation energy between constant‐load and constant‐stress creep tests. The obtained values of the stress‐dependent activation energies are, in both types of test, considerably higher than the activation energy for lattice diffusion. This is in good agreement with the literature data, although the obtained activation energies are not so strongly stress dependent. The Monkman‐Grant relation showed that the minimum creep strain rate is not quite inversely proportional to the time‐to‐rupture for both constant‐load and constant‐stress creep tests.
Study on the Formation of Open‐Eye and Slag Entrainment in Gas Stirred Ladle
Authors: Thunman M. , Eckert S. , Hennig O. , Björkvall J. , Sichen Du
Published: December 2016

Laboratory experiments were carried out to study the phenomena related to open‐eye formation in ladle treatment. Ga‐In‐Sn alloy with a melting temperature of 283 K was used to simulate the liquid steel, while MgCI2‐Glycerol(87%) solution as well as HCl solution were used to simulate the ladle slag. No open‐eye was formed at lower gas flow rates, but, occurred when gas flow reached a critical rate. This critical gas flow rate was found to depend significantly on the height of the top liquid. No noticeable amount of top liquid was observed in any of the samples taken from the metal bulk during gas stirring. To confirm this aspect, samples of slag‐metal interface were taken around the open‐eye in an industrial gas stirred steel ladle. No entrapped slag droplet was found in the solidified steel within the region between the interface and 2 cm from the interface. The accordance of the laboratory and industrial results suggests that the entrainment of slag into the steel bulk around the open‐eye cannot be considered as the major contribution to inclusion formation.
Study on Mass Transfer Characteristics in an AOD Converter Bath under Conditions of Combined Side and Top Blowing
Authors: Wei Ji‐He , Zuo Huai‐Ying
Published: December 2016

The mass transfer characteristics in a steel bath during the AOD refining process with the conditions of combined side and top blowing were investigated. The experiments were conducted on a water model unit of 1/4 linear scale for a 120‐t combined side and top blowing AOD converter. Sodium chloride powder of analytical purity was employed as the flux for blowing, and the mass transfer coefficient of solute (NaCI) in the bath was determined under the conditions of the AOD process. The effects of the gas flow rates of side and top blowing processes, the position arrangement and number of side tuyeres, the powdered flux particle (bubble) size and others on the characteristics were examined. The results indicated that, under the conditions of the present work, the mass transfer coefficient of solute in the bath liquid is in the range of (7.31×10−5‐3.84×10−4) m/s. The coefficient increases non‐linearly with increasing angle between each tuyere, for the simple side blowing process at a given side tuyere number and gas side blowing rate. The gas flow rate of the main tuyere has a governing influence on the characteristics, and the gas jet from the top lance decreases the mass transfer rate, the relevant coefficient being smaller than that for a simple side blowing. Also, in the range of particle (bubble) size used in the present work and with all other factors being constant, raising particle (bubble) size increases the coefficient. Excessively fine powder particle (bubble) sizes are not advantageous to strengthening the mass transfer. With the oxygen top blowing rate practiced in the industrial technology, the side tuyere arrangements of 7 and 6 tuyeres with an angular separation of 22.5° and 27° between each tuyere, as well as 5 tuyeres with an angle of 22.5° between each tuyere can provide a larger mass transfer rate in the bath. Considering the relative velocity of the particles to the liquid, the energy dissipation caused by the fluctuation in the velocity of the liquid in turbulent flow and regarding the mass transfer as that between a rigid bubble and molten steel, the related dimensionless relationships for the coefficient were obtained.
Advances in the Optimization of Thin Strip Cast Austenitic 304 Stainless Steel
Authors: Raabe D. , Degenhardt R. , Seliger R. , Klos W. , Sachtleber M. , Ernenputsch L.
Published: December 2016

This study is about the latest advances in the optimization of the microstructure and properties of thin strip cast austenitic stainless steel (AISI 304, 1.4301). Concerning the processing steps the relevance of different thin strip casting parameters, in‐line forming operations, and heat treatments for optimizing microstructure and properties have been studied. The microstructures obtained from the different processing strategies were analysed with respect to phase and grain structures including the grain boundary character distributions via EBSD microtexture measurements, the evolution of deformation‐induced martensite, the relationship between delta ferrite and martensite formation in austenite, and the texture evolution during in‐line deformation. It is observed that different process parameters lead to markedly different microstructures and profound differences in strip homogeneity. It is demonstrated that the properties of strip cast and in‐line hot rolled austenitic stainless steels are competitive to those obtained by conventional continuous casting and hot rolling. This means that the thin strip casting technique is not only competitive to conventional routes with respect to the properties of the material but also represents the most environmentally friendly, flexible, energy‐saving, and modern industrial technique to produce stainless steel strips.
New Stainless Steel Solutions as Economic Alternatives to Classical 1.4301 Austenitic Grades
Authors: Mithieux Jean‐Denis , Kostoj Valérie , Chassagne Francis , Charles Jacques
Published: December 2016

In the recent situation of a historically high nickel price, austenitic stainless steels, such as 1.4301, became too expensive compared to their actual technical value in many applications. This paper presents two new stainless steel grades developed by ArcelorMittal to replace 1.4301. The first one is a 20%Cr ferritic grade. The second one is a low‐Ni Cu‐bearing austenitic grade. The choices in the compositions are described as a function of the technical requirements, economical target and the production process limitations. The final properties are discussed as a function of the composition and compared with 1.4301 and other existing stainless steels. Finally, the complementarities of these two new grades are highlighted in regard to the different application markets considered.
Evolution of Microstructure and Texture during Hot Torsion of Ferritic Stainless Steels Stabilized by Nb and Ti
Authors: de Oliveira Tarcisio R. , Montheillet Frank
Published: December 2016

The study was carried out to understand the mechanisms occurring during dynamic recrystallization of hot deformed 11% chromium stabilized ferritic stainless steels and to compare the behaviour induced by various types of stabilization. The experimental temperatures ranged from 800 to 1150°C and strain rates from 10−2 to 15 s−1. The development of the textures and microstructures was analysed using EBSD maps. It was observed that continuous dynamic recrystallization occurs in all materials starting at the onset of straining. Niobium has a more pronounced influence on hardening than titanium during hot deformation. The D2 component was found as the major texture component at the steady state for the torsion tests conducted along the negative shear direction. It was likely to be formed by the combination of straining and growth of the grains exhibiting both low stored energy and low rotation rate of the crystallographic axes. The texture evolution was the main reason for the flow stress behavior during the hot torsion tests.

A complementary study was carried out to understand the texture formation occurring during the direct (negative shear direction) and reversed (positive shear direction) hot torsion. After reversion of the shear direction, i.e. during positive shear, the above major texture component is gradually changed into the D1 component. Using the method of Continuum Mechanics of Textured Polycrystals, the stress evolution is explained by the volume fraction changes of each component at various strains, associated with their respective Taylor factors. This simplified approach leads to a good agreement with experimental results.
Analysis of the Strain‐Induced Martensitic Transformation of Retained Austenite in Cold Rolled Micro‐Alloyed TRIP Steel
Authors: Krizan D. , De Cooman B. C.
Published: December 2016

The stability of retained austenite and the kinetics of the strain‐induced martensitic transformation in micro‐alloyed TRIP‐aided steel were obtained from interrupted tensile tests and saturation magnetization measurements. Tensile tests with single specimens and at variable temperature were carried out to determine the influence of the micro‐alloying on the Msσ temperature of the retained austenite. Although model calculations show that the addition of the micro‐alloying elements influences a number of stabilizing factors, the results indicate that the stability of retained austenite in the micro‐alloyed TRIP‐aided steels is not significantly influenced by the micro‐alloying. The kinetics of the strain‐induced martensitic transformation was also not significantly influenced by addition of the micro‐alloying elements. The addition of micro‐alloying elements slows down the autocatalytic propagation of the strain‐induced martensite due to the increase of the yield strength of retained austenite. The lower uniform elongation of micro‐alloyed TRIP‐aided steel is very likely due to the presence of numerous precipitates in the microstructure and the pronounced ferrite grain size refinement.
Characterisation of Dispersed Nano‐Sulphides Precipitated in Low Carbon Steel Solidified under High Rate of Cooling
Authors: Garbarz Bogdan , Marcisz Jarosław
Published: December 2016

The aim of this study was to investigate size distribution, chemistry, thermal stability and deformability of nano‐sulphides finer than about 100 nm formed in low carbon steel solidified under high rate of cooling and to assess the effect of the nano‐sulphides on the properties of steel. Laboratory mini‐ingots of low carbon steel containing various amounts of Mn, Cu and S, solidified under conditions simulating the direct strip casting process, were used as experimental material. Nano‐sulphides of MnS, (Mn,Cu)S, CuS, Cu2‐xS and CuS2‐x were identified in substantial quantities (volume fraction up to 3 ·10−4) using TEM techniques. It was shown that interaction between the nano‐sulphides and migrating grain boundaries of austenite occurred during annealing and in the course of thermomechanical processing resulting in grain refinement. Nano‐sulphides of MnS and (Mn,Cu)S type were also identified in significant quantities (volume fraction up to 6 ·10−4) in the shell and corner areas of commercial continuously cast billet.
Behaviour of Longitudinal Cracks on Slab Surfaces in V‐H Rolling Processes
Authors: YU Hai‐Liang , LIU Xiang‐Hua , REN Xiao‐Jia
Published: December 2016

The behaviour of longitudinal cracks on slab surfaces in multi‐pass vertical‐horizontal rolling processes was simulated by the finite element method (FEM). The influence of friction coefficients and fillet radii of grooved edge rolls on the closure and growth of cracks were analysed in regard to crack shape and crack length elongation ratio. The results indicate that the crack width increases both with increasing friction coefficient and with increasing fillet radii of the grooved edger rolls; the crack length increases as the fillet radii increase in V1 and H1 passes, and decreases as the fillet radii increase in V2 ~ H3 rolling. Moreover, the cracks become longer under a higher friction coefficient. Experiments of the behaviour of longitudinal cracks on slab surfaces in multi‐pass V‐H rolling processes were investigated taking lead as model material for the hot rolling of steel. The calculated results showed similar deformation variations compared to the experimental ones.
Oscillating Jet Flows in a Thin Slab Mold and their Influence on Meniscus Stability
Authors: Torres‐Alonso E. , Morales R.D. , Palafox‐Ramos J. , Ramírez‐López P.
Published: December 2016

Sustainability of oscillating liquid steel jets discharging from a submerged, two‐port entry nozzle in thin slab molds has been studied through a water model and mathematically simulated using the Reynolds Stress Model of turbulence combined with the Volume of Fluid model to capture dynamics of the water‐air interface. At casting speeds of 5 and 7 m/min, both jets yield long range time‐dependent Reynolds stresses with high gradients which induce oscillating upper roll flows in the mold providing permanent flow asymmetry. Intermittent vortexes at the water‐air interface are generated by the interaction between the flow arising from the upper roll toward the SEN and a high velocity flow which goes through the gap between the SEN shaft and mold wall oriented toward the narrow wall. These flows gather at expansion of the mold funnel generating intermittent vortexes. Meniscus oscillation decreases in narrower molds even at high casting speeds. At lower casting speed like 5 m/min meniscus oscillation decreases considerably in wide and narrow molds. Turbulence understanding in thin slab molds would help to design submerged entry nozzles for higher steel casting speeds through wide molds with better meniscus stability.
Investigation of Friction Force between Mould and Strand Shell under Sinusoidal and Non‐sinusoidal Oscillation in Continuous Slab Casting
Authors: Zang Xinyang , Wang Xudong , Ma Yong , Yao Man , Zhang Li
Published: December 2016

Friction force is an important parameter to evaluate powder lubrication and reflect the interaction between mould and strand shell. A non‐sinusoidal oscillation pattern emerges under high speed continuous casting, the characteristic of which is that the time of upward motion is longer than that of the downward motion within one cycle. In the present research experiments were performed on a slab continuous caster with a strand size of 1000 mm ×120 mm. The friction forces of sinusoidal and non‐sinusoidal oscillation under the same parameters were calculated and comparatively analysed. The results show that the friction forces of both oscillation patterns approximately change along with velocity, and present a trend to a trapezoid wave, but there is a phase difference between the friction force and relative velocity. Compared with sinusoidal oscillation, the non‐sinusoidal oscillation pattern exhibits some important advantages as follows; the maximal and average compressive forces and the compressive force work acting on the strand shell are all higher, the maximal tension is lower, and the actual amount of negative strip is higher. These advantages effect better healing of surface cracks and strand demoulds, and reduce the generation and expansion of cracks, consequently improve the surface quality.
Analysis of the Nails from the Roman Legionary at Inchtuthil
Authors: Mapelli Carlo , Nicodemi Walter , Riva Riccardo F. , Vedani Maurizio
Published: December 2016

This study is focused on the nails found at Inchtuthil, Perthshire (UK) dating to 87 A.D., The investigated nails were subjected to a preliminary radiographic analysis in order to point out the distribution of significant non‐metallic inclusions within the metal bulk. After the sectioning of the sample, an accurate optical microscopy examination was performed in order to study the different structural constituents of the microstructure. SEM‐EDS analysis allowed to quantitatively characterise the chemical composition of non‐metallic inclusions, while SEM‐EBSD examination revealed the crystallographic textures of the examined alloy. This information, coupled with the measurements of the micro‐hardness suggests a new hypothesis on the plastic deformation process adopted for the realization of the observed nails.
Influence of Aspect Ratio on Fluid Flow and Heat Transfer in Mould when Using Swirl Flow during Casting
Authors: Kholmatov S. , Takagi S. , Jönsson P. , Jonsson L. , Yokoya S.
Published: December 2016

Mathematical modelling was used to study the effect of a changed aspect ratio of a continuous casting mould on the resulting flow field in the upper part of the mould when using a swirl flow in the nozzle. Model predictions were initially compared to physical modelling data. More specifically, the predicted axial velocities were found to differ only at the most ~3 mm/s from the measured data. Thus, the model was concluded to be sound. By changing the aspect ratio of a billet mould from 1 to 3 systematically, a numerical analysis of the mould region of a billet continuous caster was performed with a novel injection concept using swirling flow in the immersion nozzle in order to control the heat and mass transfer in the continuous casting mould. The predictions showed that the aspect ratio of the mould has a large influence on the flow field in the upper part of the mould. The meniscus temperature was found to increase with an increasing aspect ratio from 1 to 2, but the maximum temperature was found to decrease when the aspect ratio was increased above 2.
Ratio between Unconsumed Coal and Coke Particle in BF Dust
Authors: WU Keng , CHEN Hongfei , XU Wanren , HE Haixi , ZHOU Xiang , FEI Sanlin
Published: December 2016

The particle size distribution in BF dust (gravitational dust and sludge) at Baosleel was measured. 85 % of the particles in the sludge are smaller than 149 μm, while 60 % of the particles in the gravitational dust are in the range 74~297 μm. It was found by microscopic analysis that the structure of unconsumed coal is different from that of the coke particles. Based on the carbon status in BF dust, the proportion of carbon from unconsumed coal and coke particles was determined by microscopic analysis at different PCI rates at Baosteel. The unconsumed coal ratio in the carbonaceous substances (Φ) in BF dust at Baosteel could be determined and then the percentages of unconsumed coal and coke particles in BF dust were obtained.
Influence of SiO2 Addition on the Properties of Al2O3‐CaO‐CaF2 Slag
Authors: Medved Jožef , Lamut Jakob , Zdovc Miro , Mrvar Primož
Published: December 2016

The Al2O3‐CaO‐CaF2 slag system is used in making special quality steels by the electro‐slag re‐melting process (ESR). The purpose of our investigation was to analyse ESR slag that contained SiO2. The slag samples with different SiO2 fractions (0 ‐ 20 mass %) were examined by chemical analysis, differential thermal analysis, simultaneous thermal analysis, X‐ray diffraction, electron microscopy and wetting angle measurement. With addition of SiO2 the polymerization of slags was increased due to the formation of new silicate complex compounds that influenced their melting points and wetting angles.
Assessment of Segregation in Hot Tear Cracks
Authors: Preßlinger Hubert , Ilie Sergiu , Fluch Judith , Reisinger Peter
Published: December 2016

In solidified slabs different types of segregations such as crystal segregation (micro segregation), centre segregation (macro segregation) and hot tear segregation (HTS) may occur. The present paper examines the segregation behaviour of different elements in hot tear cracks depending on the carbon content. The aim of this work is to determine the segregation factors in the hot tear cracks filled with residual melt and compare with micro and macro segregation. Within the scope of this examination, a microanalytical assessment was made of eight slab samples with different steel grades each showing different types of hot tear cracks that had been healed up by an inflow of residual melt. The hot tear cracks are located outside the primary dendrites in the dendritic interstices, parallel or transversal to the direction of casting. Segregation in the cracks healed up by residual melt depends on the carbon content and will become more pronounced as the carbon content increases. The intensity of segregation for the various elements in the hot tear cracks (hot tear crack segregation) is between that of crystal segregation and centre segregation. The thickness of the segregated zone in the hot tear crack area is 30 ‐ 50 μm. Apart from an enrichment of the alloying elements manganese, silicon and chromium, the healed up hot tear cracks also contain secondary precipitates of sulphides and niobium‐titanium‐carbonitrides. Towards the slab centre, the latter can cause, among other things, the development of niobium‐titanium‐carbonitrides (Nb1‐x, Tix)(C1‐y, Ny) networks in the primary dendritic interstices.
Heavy Wall Thermo ‐ mechanically Rolled Plates for Offshore Construction Use
Authors: Heigl Gemot , Lengauer Harald , Hodnik Peter
Published: December 2016

The growing energy consumption of the world made the exploitation of many offshore oil & gas fields feasible. In order to have the benefit of high strength and toughness together with good weldability, thermo‐mechanical rolling has been developed. In the construction of offshore structures plate thicknesses in excess of 50 mm are common which could up to now only be manufactured with restricted mechanical properties and a loss of productivity. The necessary fine grain structure is obtained by a minimum of four times total deformation in the thermo‐mechanical rolling process with accelerated cooling. For a steel mill this means that a change to a higher slab thickness was obligatory. In the plate mill the main drives were replaced in order to increase the torque and as a consequence get better deformation in the centre of the slabs. The accelerated cooling unit was revamped to a higher water pressure to obtain higher cooling rates and additionally enlarged to reach lower cooling stop temperatures. The results obtained with this new concept are presented in terms of strength, toughness and weldability for a 75 mm plate. This together with fracture mechanical data on the plate and on the weld demonstrates the effectiveness of the new technical concept and set a new benchmark in steel properties.
Local Strain‐Hardening in Sheet Metal and Forging Components
Authors: Behrens Bernd‐Arno , Hübner Sven , Knigge Julian , Voges‐Schwieger Kathrin , Weilandt Katrin
Published: December 2016

Metastable austenitic stainless steel has a good adaptability for different challenges in forming processes due to its good ductility and high corrosion resistance. Metastable austenitic steels are applied in the automotive industry as well as in the chemical and oil industries. The spectrum could be enlarged by optimised properties due to locally adapted material characteristics in components and assemblies. Load adapted components can be produced by selective generation of transformation‐induced martensite. The formation of martensite is realised in special forming processes of sheet metal and bulk metal components. By an upsetting process the martensitic microstructure is generated in cylindrical raw parts. One example of martensite generation in sheet metal forming is the structuring of certain areas with small buckles of pins, or the defined stretching of a local area. By this local attributes the components could be strengthened in critical areas. Alternatively, the local martensitic high‐strength areas and austenitic ductile regions lead to a defined buckling of components in case of a crash. In this paper the mechanism of martensite evolution is described and investigations and their results on sheet metal and bulk metal components are presented. A testing routine has been developed to get fast and precise information about the martensite content. In experimental studies promising results have been achieved in first crash tests with a sample geometry and in the generation of ‘structure fields'. Additionally, a suitable mathematical description of martensite evolution during deep drawing processes has been developed. The model has been successfully implemented in a finite element analysis and is used to study various arrangements of structure fields in sheet metal.
Production of Tailored High Strength Hybrid Sandwich Structures
Authors: Palkowski Heinz , Lange Günther
Published: December 2016

This project deals with the manufacturing and subsequent treatment of partially strengthened, three layered, symmetrical sandwich structures. Those sandwich materials have the advantages to combine the properties of the used mono‐materials. Additionally, they have a good damping behaviour because of the soft core and good stiffness and a good corrosion resistance if stainless steel sheets are used as cover. The characteristics of such structures are even more improved by the specific local influence of partial reinforcement within the sandwich material. With this type of strengthening, complex material properties can be developed, e.g. high strength with high stiffness, good thermal joining properties at the place of strengthening, as well as an improved strength and strength absorbing ability. The forming behaviour of such composite materials is still unknown. In this research project different sandwich materials ‐ with and without reinforced elements ‐ are analysed in bending tests and in deep‐drawing investigations.
Increasing Rigidity and Strength using Local Effects of Bead‐on‐Plate Laser Welding Seams
Authors: Schimek Mitja , Meier Oliver , Ostendorf Andreas , Haferkamp Heinz
Published: December 2016

In order to achieve graded strength properties and to improve the rigidity of metallic materials, side effects of the laser joining process are used. Local physical and geometrical effects which have only been observed as side effects are to be used purposefully. The investigations take place in context of the SFB 675 “high‐strength metallic structures and joints by setting up scaled local material properties”. The energy needed to produce bead‐on‐plate welding seams can be limited to a small area of the workpiece by using a focused laser beam with a diameter of tenths of a millimetre. The heat affected zone of a laser beam is very small. In comparison to other welding procedures, lower heat input is the main reason that basic material characteristics remain unaffected after welding. The progressive development of laser beam sources to higher available laser output power has extended their spectrum of use in the field of joining technologies [1, 2].

It should be pointed out that local physical and geometrical effects can be used to achieve specific material characteristics. Bead‐on‐plate laser welding seams were produced to demonstrate that strength and rigidity can be increased in metal sheets. First investigations are carried out on the micro‐alloyed high‐strength steel H340LAD. The sheets were tested using tensile tests and also with 3‐point and 4‐point bending tests. Six different specimens were investigated, one without welding seams and five with different laser based welding seam types. The tensile and bending tests showed that higher forces were needed to rupture or to bend the laser welded specimens. Furthermore, the investigations showed that the strength of the specimens was increased in comparison to the specimens without welding seam.
Development of New Combined Manufacturing Technologies ‐ Influence of the Cutting Process on Workpiece Properties
Authors: Denkena Berend , Boehnke David , Breidenstein Bernd
Published: December 2016

Properties of materials for high‐strength structure components are influenced by production processes. These influences can be augmented by a combination of two presently consecutively executed process steps. The presented work shows first results in the development of novel combined manufacturing technologies, which along with prospective tools use this effect to adjust the material properties locally, adapted to the requirements. The combination consists of a merging of the process steps ‘material separation’ (metal cutting) and ‘changing properties’ (rubbing, rolling) to one single process step. For this purpose novel combined tools have to be developed. For the estimation of the possibilities of properties changes by combined processes at first the influences of single processes have to be determined. This contribution presents results of a “material separation” process. The investigated material is the industrially important aluminium wrought alloy AI7075‐T6, the applied process is orthogonal turning, the process parameters varied are cutting speed and feed as well as the tool geometry. Cutting force and feed force are measured, and the process influences on surface and subsurface properties are determined.
Influence of Forming on the Cyclic Behaviour of TRIP700
Authors: Esderts Alfons , Masendorf Rainer , Medhurst Tim
Published: December 2016

During low cycle fatigue tests on TRIP700 for a current research project some anomalies were noticed. In comparison to previous fatigue life tests on nominally identical material, substantially different material characteristics were measured. The cyclic strength of the current lot of material has substantially increased. It is investigated where the differences come from and whether an influence from forming can cause such changes of the cyclic behaviour.
The Effect of the Transition Metal Oxide Content of a Mold Flux on the Radiation Heat Transfer Rates
Authors: Wang Wanlin , Cramb Alan W.
Published: December 2016

Heat transfer in the mold of a steel continuous casting machine strongly influences cast surface quality. Transition metal oxides have been widely used in mold slags in continuous casting to aid in liquid pool formation and enhance melting rates. Although a few research studies have been carried out to investigate the thermal properties of mold slags containing transition metal oxides, very few studies have directly correlated their effect on radiation heat transfer rate in continuous casting. This study investigates the radiation heat transfer rates across a mold flux film and determines the influence of the transition metal oxides, MnO and Fe2O3, on these rates. It is found that additions of 10% MnO or 5% Fe2O3 reduce the radiation heat transfer rate by approximately 25% and increase the adsorption coefficient from 400 to 1800 m−1.
A mandarin text‐to‐speech technique implemented on a PIC‐based microcontroller platform
Authors: Yeh Cheng‐Yu , Chang Chih‐Hsuan
Published: December 2016

In this paper, a Mandarin text‐to‐speech (TTS) technique is employed to achieve the implementation of a voiced E‐book on the PIC‐based embedded platform. A transformation from the text of E‐book to the corresponding speech can help blind users and make the reading more effortless and relaxed. Both the microcontroller with a PIC32 Ethernet Starter Kit (80 MHz, 32‐bit, 128 kB SRAM, 512 kB Flash) and the Multimedia Expansion Board designed by Microchip Technology Inc. are adopted as the embedded platform. Four subsystems, namely text analysis, a recurrent neural network‐based prosodic generator, a synthesis unit generator with 411 Chinese syllabic waveforms, and a pitch‐synchronous overlap‐add‐based speech synthesizer, are made in the Mandarin TTS system and are implemented with C programming language. Experimental results find that a system requirement of 1.66 MB storage memory and less than 25.4 kB runtime memory, as well as 21.3% CPU runtime, is sufficient for real‐time operation such that a natural and fluent speech with a 16‐bit PCM at 8 kHz sampling rate is provided. The performance of the PIC‐based Mandarin TTS system is demonstrated to be good. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Recent advances and outlook in industrial instrumentation and mechatronics control
Authors: Shimada Akira
Published: December 2016

Recent years have been characterized by marked progress in industrial instrumentation and mechatronics control technology. This year commemorates the fifth publication year of the IEEJ Journal of Industry Applications (emIEEJ J. IA). Additionally, the Mechatronics Control (MEC) technical committee was formed 3 years ago following a separation from the Industrial Instruments and Control (IIC) technical committee in order to further enhance their respective social contributions. The increased activity of both committees also contributed to the progress of the Journal. This paper discusses the recent advances and outlook in the technical field of industrial instrumentation and mechatronics control based on papers published in the IEEJ J. IA and a few other significant papers, which consider the current activities of the various committees. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Visual tracking in HEVC compressed videos
Authors: Oh Seoung‐Jun , Yoon Seongro , Lee Dongkyu
Published: December 2016

We present a robust visual tracking algorithm to track a rigid object in high efficiency video coding (HEVC) compressed‐domain. Based on a Markov random field model, we estimate the target object state by using motion vector extracted from compressed bitstream. Especially, we employ residual discrete cosine transform (DCT) coefficient (RDC) in the bitstream as the shape information of the target object to prevent the drift problem. The measurements of motion vector and RDC are adaptively reflected through our potential functions for the target state. Our experiments on test sequences compressed by an HEVC encoder show that it is robust to track rigid objects. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
SiC SBDs selection method based on loss analysis of boost converter
Authors: Sasaki Masato , Umegami Hirokatsu , Yamamoto Masayoshi
Published: December 2016

Silicon carbide schottky barrier diodes (SiC SBDs) have much better characteristic than Si PiN diode in high voltage applications because SiC SBDs do not have recovery effect. However, simple replacing is not the most effective way. In a boost converter, the power loss caused by the SiC SBD can be divided into the conduction loss of the SiC SBD and the loss caused by the energy stored in the junction capacitance of the SiC SBD. Therefore analysis of not only the conduction loss but also the loss caused by the energy stored in the junction capacitance of the SiC SBD can realize the SiC SBD selection to improve the efficiency of the boost converter. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Learning in the Company of Others: Students and Teachers Collaborating to Support Wonder, Unease, and Understanding
Authors: Gale Richard A.
Published: December 2016

Building collaboration with students into the teaching process brings with it many benefits for learning, but it also requires accepting the risk and unease that comes from redefining the roles of students and teachers.
How Students, Collaborating as Peer Mentors, Enabled an Audacious Group‐Based Project
Authors: Bernstein Jeffrey L. , Abad Andrew P. , Bower Benjamin C. , Box Sara E. , Huckestein Hailey L. , Mikulic Steven M. , Walsh Brian F.
Published: December 2016

We discuss how a professor worked with six students to design and implement a complex teaching strategy for a course, and used the students’ assistance to create a sustainable model for future iterations of the course.
Exploring Academia: Professionalization and Undergraduate Collaboration
Authors: Galantucci Ellen G. , Krcatovich Erin Marie‐Sergison
Published: December 2016

Early opportunities for academic professionalization—through opportunities to teach and research in collaboration with professors—provide undergraduates with the tools needed to be successful in graduate school and in subsequent employment. Here, we advocate for more professors to consider collaboration with undergraduates, so students may practice leadership skills within the academic setting.
Collaborating in Dialogue for an Optimal Leadership Education
Authors: Werder Carmen , Garcia Joseph , Bush Jamie , Dallstream Caroline
Published: December 2016

Four different perspectives—from the director of a scholarship of teaching and learning dialogue forum, the director of a leadership institute, and two undergraduate students—join together to discuss a collaboration in optimizing leadership education at Western Washington University.