bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stand des Einsatzhärtens aus industrieller Sicht*
Authors: Liedtke D. 
Published: December 2013

Kurzfassung

Das Einsatzhärten ist nach wie vor das am meisten angewendete Wärmebehandlungsverfahren in der Stahl verarbeitenden Industrie. Es ermöglicht, Bauteile aus den leicht bearbeitbaren Einsatzstählen herzustellen und diese mit einer Randschicht zu versehen, die durch eine hohe Härte, Festigkeit und Druckeigenspannungen bei zweckentsprechender Kernfestigkeit gekennzeichnet ist. Damit werden die wichtigen Funktionseigenschaften Schwingfestigkeit und Verschleißwiderstand erreicht.
Beleuchtet werden die in der industriellen Fertigung derzeit übliche Verfahrenstechnik zum Aufkohlen und Härten, die gebräuchlichen Aufkohlungs- und Abschreckmittel sowie die Mess- und Regeltechnik. Auf bewährte Möglichkeiten wird hingewiesen, mit denen der Diffusionsprozess Aufkohlen wirtschaftlich gestaltet und die daraus resultierende Problematik des Werkstoffverhaltens und der Anlagentechnik beherrscht werden kann.
Aus heutiger Sicht erscheint es notwendig, durch intensives „distortion engineering“ den Aufwand für das wegen der Maß- und Formänderungen unvermeidliche Nachbearbeiten zu minimieren. Damit verbunden ist auch der Wunsch, über allgemein handhabbare Simulationsprogramme zu verfügen, mit denen sich die durch ein Einsatzhärten zu erwartenden Bauteil-Eigenschaften treffsicher voraussagen lassen. Ein wertvoller Beitrag für die Qualitätssicherung wäre sicher auch eine Messmethode, mit der sich das Wachsen der Aufkohlungsschicht online verfolgen und anzeigen ließe.
Assessment and optimisation of energy efficiency in heat treatment plants
Authors: Krail J. , Buchner K. , Altena H. 
Published: December 2013

Abstract

The last years are marked by heavily fluctuating energy costs and uncertainties in energy supply. Prognoses exhibit a dramatic gap between supply and demand on fossil energy carriers in the years to come. Energy efficiency is one key to cover the future worldwide energy demand. In Austria and Germany process heat represents a considerable portion of total energy consumption. Targeted primary measurements and a consequent utilisation of waste heat in plants may lead to a significant improvement of plant efficiency and in consequence to a reduction of CO2-emissions. By way of a gas-fired pusher-type furnace for carburising internal and external efficiency increasing measures are demonstrated and their influence on the overall process are assessed.
Low temperature gaseous surface hardening of stainless steel
Authors: Christiansen T. L. , Somers M. A. J. 
Published: December 2013

Abstract

The present contribution gives an overview of some of the technological aspects of low temperature thermochemical treatment of stainless steel. Examples of low temperature gaseous nitriding, carburising and nitrocarburising of stainless steel are presented and discussed. In particular, the morphology, microstructure and characteristics of so-called expanded austenite “layers” on stainless steel are addressed.
Evolution of residual stress in the diffusion zone of a model Fe-Cr-C alloy during nitriding*
Authors: Jegou S. , Barrallier L. , Kubler R. , Somers M. A. J. 
Published: December 2013

Abstract

Development and evolution of compressive residual stress during nitriding treatment are studied. A model carbon iron-based alloy Fe-3wt.%Cr-0.35wt.%C was nitrided in gas at 550 °C for different times. Microstructural investigation indicated an influence of the transformation and the associated carbon diffusion on the in-situ relaxation of residual stress induced by nitride precipitation. The transformation of initially present carbides into nitrides and the associated carbon accumulation ahead of the nitriding front is particularly taken into account. The distribution of residual stress in the nitrided case was predicted with a self-consistent mechanical model, using the volume changes associated with the phase transformations. To this end the nitrogen and carbon concentration distributions were converted into the equilibrium phase fractions of carbides and nitrides. An excellent correlation was obtained between experimental (X-ray diffraction analysis) and, thus, calculated independent residual stress distributions in the ferrite matrix.
Microstructure, hardness, corrosion and dry wear of 17wt%Cr-3wt%C-7wt%Mo cast iron
Authors: Wiengmoon A. , Pearce J.T.H. , Imurai S. , Chairuangsri T. 
Published: December 2013

Abstract

The microstructure of a 17wt%Cr-3wt%C white cast iron with relatively high Mo addition (7 wt.-% Mo) has been investigated by X-ray diffraction, light microscopy, scanning electron microscopy and transmission electron microscopy together with energy dispersive X-ray spectroscopy. Mo dissolves partly in the matrix and partly in the typical Cr-rich M7C3 eutectic carbide and also leads to microstructural modification by forming a fine Mo-rich lamellar structure at interdendritic regions with a volume fraction of 11 %. The Mo-rich phase in this lamellar structure may also be a carbide of the M6C type and is believed to form at the later stage of solidification by a subsequent eutectic reaction. Destabilization heat treatment at 1000°C for 4 hours followed by air hardening results in precipitation of M7C3 and M23C6 secondary carbides, transformation of dendritic and eutectic austenite to martensite with some austenite being retained, and modification of local chemical composition, importantly an increase in the Mo and C content in the matrix. This causes a significant improvement in hardness, corrosion and dry wear properties. Tempering at 450°C for 4 hours leads to more temper-carbide precipitation and formation of ferrite, possibly by decomposition of retained austenite. However, an improvement in properties was not observed.
Niederdruckaufkohlung von chromhaltigen Sinterstählen für Zahnräder
Authors: Dlapka M. , Danninger H. , Gierl C. , Altena H. , Stetina G. , Orth P. 
Published: December 2013

Kurzfassung

In den letzten Jahren haben chromhaltige pulvermetallurgische Stähle auf der Basis vorlegierter Pulver wie Astaloy CrL (Eisen + 1,5% Chrom + 0,2% Molybdän) und Astaloy CrM (Eisen + 3% Chrom + 0,5% Molybdän) zunehmend Interesse gefunden. Die Gründe hierfür sind einerseits die niedrigeren Kosten für Chrom verglichen mit traditionellen Legierungselementen in der Pulvermetallurgie, wie Molybdän, Nickel und Kupfer, andererseits die mittlerweile in der Industrie verfügbaren deutlich verbesserten Sinteröfen, die eine sauerstofffreie Atmosphäre und hohe Temperaturen ermöglichen. Bei der Verwendung entsprechender Sinter- und Wärmebehandlungsbedingungen erzielen diese chromhaltigen Stähle hervorragende mechanische Eigenschaften bei relativ niedrigen Materialkosten.
Allerdings ist für diese Materialien eine konventionelle Gasaukohlung mit anschließender Ölabschreckung nicht möglich, da die Kohlungsgase immer signiikante Mengen an sauerstohaltigen Verbindungen enthalten, welche in die ofenen Poren der Sinterteile eindringen können und Oxidation der Teile, nicht nur der Oberläche, sondern auch des Inneren, bewirken, was zu einer deutlichen Versprödung führen würde. Auch kann das Härteöl die Poren kontaminieren, was die Notwendigkeit für teure Waschoperationen der Teile bedingt und damit zu erhöhten Kosten führt.
In der hier vorliegenden Arbeit wurde als Alternative für diese oxidationsempindlichen, chromhaltigen Materialien die Niederdruckaukohlung kombiniert mit einer Hochdruckgasabschreckung untersucht. Es konnte gezeigt werden, dass diese Wärmebehandlung eine sehr gute Methode für die Randschichthärtung chromhaltiger Sinterstähle ist.
Analysis of surface layer characteristics for sequential cutting operations
Authors: Schulze V. , Osterried J. , Strauß T. , Zanger F. 
Published: December 2013

Abstract

For manufacturing processes like milling, broaching and skiving tools with multiple cutting edges are used. The geometry and the characteristics of the machined components are the result of sequential cuts. A finite element model is built up including the sequential cutting by transferring component states between work piece models. The model is validated by comparing residual stresses between numerical and experimental results. Small element sizes allow for a detailed resolution of quantities describing the component state. Characteristics of the specific depth profiles are used for the analysis of residual stresses. The influence of process parameters and the number of simulated sequential cuts are examined. Sequential cuts show an influence on surface residual stresses. Residual stresses decrease for low cutting velocities and slightly increase for high cutting velocities. Tensile stresses also reach to deeper areas of the surface layer with increasing number of cuts. Compressive stresses pass through a significant maximum before decreasing to a constant value. A steady stress state is identified after ten sequential cuts.
Microstructure evolution of the air-hardening steel LH800® due to heat treatment
Authors: Schaper M. , Grydin O. , Nürnberger F. 
Published: December 2013

Abstract

To characterize microstructural and properties changes of the air-hardening steel LH800® due to heat treatment various experimental investigations were carried out. Amongst others, the TTA-austenite grain size diagram, the martensite transformation curve and the tempering diagram were determined. Based on the experimental data the coefficients of the Koistinen-Marburger model were calculated. This allows for a mathematical description of the martensite formation during hardening. The obtained data can be used not only to improve the experimental process design but also to provide information to improve existing numerical models.
Non-destructive determination of local damage and material condition in high-performance components
Authors: Reimche W. , Bruchwald O. , Frackowiak W. , Bach Fr.-W. , Maier H. J. 
Published: December 2013

Abstract

In modern aircraft engines, a high number of complex high-performance components are employed, which are partly subjected to extreme loading. For instance, the high-pressure turbine blades of the first stage after the combustor are both thermally-mechanically loaded and experience severe corrosive attack. Therefore they are furnished with several protective systems in order to improve the fatigue life and reliability of the high-temperature material blades employed. A ceramic thermal barrier coating insulates the internally and film-cooled blades against the hot gas stream whilst the underlying layer (PtAl, Al, MCrAlY) protects the substrate material against corrosive attack and oxidation. Owing to the low electrical conductivity of the materials employed in the multilayered system of the high-pressure turbine blades with layer thicknesses of 20–150 μm, conventional eddy-current and thermographic technologies are only suitable to a limited extent to non-destructively detect the condition of the individual layers separately from the substrate material. In contrast to this, with the aid of multi-parameter, high-frequency eddy-current technologies and high-frequency induction thermography using pulsed excitation, the eddy-currents with test frequencies in the mega-Hertz range (up to 100 MHz) can be limited to the near subsurface and produce standard penetration depths of <50 μm; which enables the layer and substrate materials to be differentially studied. The objective of the present study was to non-destructively detect the condition of the coatings, to characterise and determine the thickness of the coating as well as to detect the condition of the substrate material and sensitively analyse local damage and defects.
Sensor für die Regelung der Kohlenstoffübertragung bei der Niederdruckaufkohlung∗
Authors: Gräfen W. , Berg H. J. , Seehafer K. , Zosel J. 
Published: December 2013

Kurzfassung
Für die zeitnahe Regelung von Anlagen zur Niederdruckaufkohlung werden robuste Sensoren und Messsysteme benötigt, die ein Signal zu dem momentan in den Werkstof übergehenden Kohlenstof liefern. Für diese Applikation wurde ein coulometrischer Festelektrolytsensor auf der Basis von stabilisiertem Zirconiumdioxid eingesetzt, der die kontinuierliche Umsetzung eines Teilstroms des Ofenabgases mit Sauerstof ermöglicht. Untersuchungen mit diesem Sensor im Labor und an einer Einkammer-Anlage im Vergleich mit einem H2-Wärmeleitfähigkeitssensor (WLD) zeigen, dass der Titrationsstrom deutlich schneller reagiert als das Signal des WLD und nach einer Kalibrierung als direktes Maß für den Kohlenstofübergang herangezogen werden kann. Der Vergleich der mit dem coulometrischen Sensor online gemessenen integralen Kohlenstofübertragung mit dem oline bestimmten Kohlenstofproil der behandelten Werkstücke zeigt im Rahmen der erreichbaren Genauigkeit eine zufriedenstellende Übereinstimmung.
Study on Surface Activity and Critical Aggregation Concentration of Sucrose Esters Containing Different Isomers of Mono-, Di- and Polyesters
Authors: Yanke Li , Shufen Zhang , Qinghui Wang , Jinzong Yang 
Published: December 2013

Abstract
We have studied the surface properties of a series of synthesized sucrose esters with different hydrophobic chain lengths (C12–C18). The critical aggregation concentration (CAC) values for sucrose stearates and palmitates primarily decrease and then increase, but the surface tension (γCAC) values all increase with decreasing the proportion of monoesters. However, in the case of sucrose laurates, the CAC values decrease with the decrease in the proportion of monoesters. Except for sucrose stearate, the CAC values for other sucrose esters decrease but the the γCAC values increase with the increase of the tail length when the proportion of monoesters is remained unchangeable. In order to further interpret the observation, the lowest-energy conformations generated by MM2 for sucrose mono-, di- and triester are given. In comparison with monoester, the molecular dimensions of diester and triester are more bulky and the structures are more three-dimensional. The sucrose esters containing lower proportion of monoesters can produce higher cross-sectional area per molecule than the monoester, and therefore have higher surface tension.
Synthesis of Novel Arylalkyl Sulfonate Surfactants
Authors: Zhigang Xu , Yu Zhao , Bing Yuan , Weihong Qiao , Zongshi Li , Lubo Cheng 
Published: December 2013

Abstract
A method of synthesizing novel arylalkyl sulfonates is introduced. Reaction conditions were assessed by the measurement of iodine value. Catalysts with little pollution were used in the study.
Comparison of Composition and Properties of Ethoxylated Dodecanoic acid obtained in the Presence of Various Catalysts
Authors: Trathnigg B. , Hreczuch W. , Szymanowski J. , Rappel C. , Hödl R. 
Published: December 2013

AbstractOxyethylation of dodecanoic acid was performed in the presence of a conventional alkaline catalyst, a homogeneous alkaline earth metal catalyst and a heterogeneous rare earth metal catalyst, respectively. As the result, three series of products were obtained in a range of average polyaddition degrees from N = 3 up to N = 9. The content of the obtained products was determined analytically by different chromatographic techniques: Size Exclusion Chromatography (SEC) with dual detection, gradient Liquid Adsorption Chromatography (LAC) with evaporative light scattering detection (ELSD), and Liquid Exclusion Adsorption Chromatography (LEAC), a new technique, which allows quantitatively accurate determination of the oligomer distribution of ethoxylates.It was found that the applied catalysts significantly influenced the obtained homologue distributions and the content of di-esters and polyethylene glycols as byproducts. Much more selective ethoxylation is observed in the presence of the multivalent metal catalysts. As the result, the equivalent product series exhibit significant differences of physicochemical properties and surface activity. The new capabilities in analytical determination of the complex mixture of ethoxylated acids and the detected substantial differences in their chemical content can give a new input for more detailed investigation of these products.
Determination of Alcohol Ethoxylate Components in Sewage Sludge
Authors: Matthijs E. , Burford M. D. , Cassani G. , Comber M. H. I. , Eadsforth C. V. , Haas P. , Klotz H. , Spilker R. , Waldhoff H. , Wingen H.-P. 
Published: December 2013

Abstract
An analytical method has been developed for the determination of alcohol ethoxylate (AE) components in sewage sludge. The method has been extensively ring tested in several industrial laboratories and concentrations in sludge samples from a number of EU countries have been obtained. The method is based on a methanol soxhlet extraction of centrifuged sludge, which is then cleaned up using an alumina column, followed by derivatisation with naphthoyl chloride and a further alumina column clean-up. The extract is analysed using high performance liquid chromatography (HPLC) with fluorescence detection. The method is capable of determining alcohol ethoxylate components in the range of C12–C18 alkyl chain lengths with an ethoxylate chain of EO4 up to approximately EO20 in sludge samples. The detection limit is approximately 20–30 mg kg−1 of total AEs in dry weight of sludge. Using the method, sludges from several European Sewage Treatment Plants (STP) were analysed. The concentration of the AEs, which are primarily linear, in digestor inlet averaged 1164 mg kg−1 (550–2947 mg kg−1) and in outlet sludges the mean value obtained was 167 mg kg−1 (<22–468 mg kg−1). At those plants in which concentrations were monitored in both inlet and outlet sludges, removal of the AEs by anaerobic digestion at the STP averaged 82% (range 61–93%). The interlaboratory relative standard deviation of the procedure was around 40% for the digester sludges analysed. The method developed provides a more accurate estimate of the environmental level of AE components compared to existing colorimetric approaches, but the method will over-estimate the concentration of alcohol ethoxylates in sludges due to the non-specific nature of the detection. However, it is sufficiently robust and accurate to estimate alcohol ethoxylates in sludges and hence concentrations that could be applied to soil.
Surface Tension and Micellization of Aqueous Alkyl Polyglucosides Solutions: Influence of the Molecular Structure and the Addition of Electrolyte
Authors: Jin Xin , Zhang Shufen , Yang Jinzong 
Published: December 2013

AbstractSugar-based surfactants have recently attracted considerable interest. In this work, the surface tension and critical micelle concentration (CMC) of alkyl polyglucosides (APGs) with differences in both alkyl chain lengths and average degree of polymerization (DP) were measured, and the effects of sodium chloride and sodium hydroxide on the surface tension and CMC of aqueous solutions of APGs were investigated. The alkyl chain length has a far stronger influence on the CMC than the degree of headgroup polymerization. The addition of sodium chloride to solutions of APGs has a relatively small effect compared with ionic surfactants. The observed effects of sodium hydroxide were explained in terms of the salting out of the hydrocarbon chains of APGs and the hydrotropic effect due to a negative charge on APGs micelles resulting in the deprotonation of the glucose fraction in strong alkaline system.
A Protocol to Examine the Colour Damage Profile of Bleach Containing Detergents
Authors: Luijkx G. C. A. , Hild R. , Krijnen E. S. , Lodewick R. , Rechenbach T. , Reinhardt G. , Phillips D. A. S. 
Published: December 2013

Abstract
In the development of new and improved bleach systems for detergents there is a need for a reliable and generally accepted protocol to test colour and fibre damage. We here describe a protocol to screen detergents on colour damage/fading under European wash conditions, using a recently developed set of dyed fabrics.
The test protocol has been evaluated in an inter-laboratory test and was found to be robust in the sense that it gave similar results in different laboratories. Hence the protocol described is recommended for testing the colour damage/fading properties of oxidative bleach containing detergents for the European market.
Process Management Based on Analysis of Surfactant Properties
Authors: König V. , Schulze L. , Haberland R. 
Published: December 2013

Abstract
One goal of optimising cleaning processes is the economic use of surfactant. To find the optimum concentration of active surfactants for a stable and high cleaning quality, a measurement technique to determine this concentration is required, in order to establish a correlation to the cleaning result.
The article introduces a modified surface tension measurement method to determine the concentration of active surfactants in process conditions. Based on this method, a new generation of inline tensiometers had been developed. These Instruments allow continuously monitoring the active surfactant concentration in a cleaning bath.
The article shows how to interpret the measurement results for the process control. Exemplarily at the use of online measurement in metal cleaning processes, the potential to provide a higher level of process quality control will be illustrated.
Are Oxygen Demands Relevant for Today's Environmental Assessment of Detergents?
Authors: Boeije G. , Klein H. J. 
Published: December 2013

AbstractThough oxygen demands are critical measurements for waste water treatment plant operation and water quality management, they are of little relevance to assess or rank the environmental quality of detergents. It is argued that: (1) No accurate measurements of the oxygen demand of bleach detergents can be made, because these products release oxygen during the measurement. (2) When waste water is adequately treated, under normal operating conditions the oxygen demand (organic loading) of the raw sewage has no influence on river quality. (3) Oxygen demand values are narrowly focused on environmental exposure, while they do not take into account the potential for ecotoxicological effects. (4) Short-term biological oxygen demand measurements are useful for the monitoring of ‘average sewage', but they are unreliable to assess the biodegradability of more specific substances or products. Instead of oxygen demands, more holistic evaluations based on risk assessment or on life cycle analysis are scientifically preferred.
Spreading Characteristics of Aqueous Surfactant Solutions on Polymer Surfaces
Authors: Dutschk V. , Breitzke B. 
Published: December 2013

AbstractThe objective of this work was the analysis of dynamic wetting behaviour of aqueous surfactant solutions on polymer surfaces in respect of spreading characteristics evaluation. Surfactants with different ionogeneity (ionics and non-ionics) in a wide concentration range were used in this study. The sessile drop method was used to measure the contact angle, base radius and height of a drop containing surfactant as functions of time. Five polymer surfaces of different surface free energy were well prepared and characterised for this study.The analysis of the time dependency of the drop base radius reveals that the long-term spreading behaviour for all surfactant solutions follows power law with exponent values much lower than 0.1 which agrees neither with the diffusion-controlled spreading nor with Tanner's law. On the basis of experimental results, we conclude that a transfer of surfactant molecules on the bare polymeric surface in front of the moving liquid takes place as described by Starov et al. The transfer time can be used as a spreading characteristic which decreases with increasing concentration as predicted by Starov et al.