bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on phosphate and sulphide capacities of CaO‐CaCl2 slags
Authors: Yang Yindong , McLean Alex , Sommerville Iain D. , McKague Alan R. 
Published: December 2016

Experiments were carried out at 1175–1350°C to study the phosphate capacity of CaO‐CaCl2 slags and the sulphide capacity was calculated according to the correlation between the two capacities. At 1200°C the logarithm of the phosphate capacity increased from 24.5 to 26.5 with increasing CaO mole fraction from 0 to 0.22 in the slags and it decreased with increasing temperature. Sulphide capacity increased both with increasing CaO mole fraction and temperature.A good linear correlation was found between slag carbonate capacity and phosphate capacity as well as sulphide capacity. Optical basicity was used to evaluate the property of the CaO‐CaCl2 slag in the present study. The value of optical basicity of CaCl2 is established as 0.63. The correlations of optical basicity with above mentioned three capacities were found to be linear.
Characterisation of technical surfaces by means of fractal geometry
Authors: Doege Eckart , Laackman Benedikt , Kischnick Bernd 
Published: December 2016

Common technical roughness parameters are not able to characterise technical surfaces clearly. Such parameters often have the same value on completely different surfaces. Only the specification of additional parameters may allow a statement about the surface character. Considering the Weierstraß‐Mandelbrot function a fractal model for the characterisation of surface profiles has been developed. One needs only two parameters to distinguish different surfaces. Thereby a surface profile is measured by means of a surface analyser. Then the fractal parameters will be determined from the data set of a measured profile. To find the suitable fractal description for a given surface the power spectra of the function and of the empirical data are used. Next the empirical power spectrum is interpreted as the power spectrum of a Weierstraß‐Mandelbrot fractal function with fractal parameters to be determined. Additionally this technique also allows the qualitative reconstruction of a previously measured profile.Series of measurements using the materials X4CrNi 18–10, St12O3 (DC01) and AIMg3 proved the model to be well applicable to sheet surfaces. The fractal parameters are more suitable to classify the surface character than the common technical roughness parameters. The next investigations will be carried out in order to verify the influence of parameters relevant for sheet metal forming (e. g. strain, contact pressure, drawing speed) on the fractal model. The whole work aims at the preparation of a law that describes the local influence of the surface character on the frictional behaviour of sheet metal forming processes. This will be prepared for the use in combination with the method of finite elements (FEM).
Thermodynamic data of the formation of titanium nitride in iron
Authors: Kunze Joachim , Beyer Bodo , Oswald Steffen , Gruner Wolfgang 
Published: December 2016

The solubility of titanium nitride in liquid iron is described by the solubility product log([%Ti][%N])1 = −17040/T + 6.40 reported by Turkdogan. The solubility in δ ferrite measured by Kunze is log<[%Ti][%N])δ = −17205/T + 5.56. Combining the solubilities in both phases and the solubilities of nitrogen the distribution equilibrium of titanium can be derived. It is characterized by the thermodynamic distribution coefficient kδ/Io,Ti = [%Ti]δ/[%Ti] = 0.40. By zone melting and secondary ion mass spectrometry of the titanium distribution kδ/ITi = 0.53 was measured. An analysis of all known data led to kδ/Io,Ti = 0.40…0.50.Measurements of the TiN solubility in austenite by heat treatment were not significant. They led to distribution coefficients between 0.07 and > 1. By zone melting in a carburizing atmosphere a distribution coefficient kγ/ITi = 0.12 was measured. From a thermodynamic analysis performed by Ohtani et al., from the TiN solubility in the melt, and from the solubilities of nitrogen kγ/Io,Ti = 0.13 was deduced. Basing on the distribution equilibria of titanium and nitrogen and on the measured temperature dependence the solubility product log([%Ti][%N])γ = −15000/T + 4.06 was obtained.
Dust formation in a BOF converter
Authors: Nedar Lotta 
Published: December 2016

Minimisation of waste and manipulation of residues to suit succeeding processes today is one of the steel works most important research areas. BOF dust is expensive to depose in landfills and difficult to recycle due to its zinc contents. The simultaneous loss of raw materials and cost increase makes it important to minimise the generation of dust. This can be done by employing better process control systems with regard to the mechanisms governing the generation. Four dust forming mechanisms can be considered in a converter: ejection of metal, ejection of slag, entrainment of charged material and vaporisation.In order to determine the importance of the four dust forming mechanisms and to characterise dust, with special emphasis to zinc, the off‐gas from a 100‐t BOF was sampled during twenty seven heats. The sampling equipment allows the sampling of both solid dust particles and vaporised elements. Samples from the first and the second part of blowing show significant differences both in chemical composition and in the origin of formation. The major dust formation mechanism is the ejection of metal and slag, respectively. Entrainment of solids plays an important role only during the first part of blowing. Vaporisation of elements from the bath is most important during the end of blowing. The formation of dust is influenced by process operation control, especially lance position, silica contents and time of charging of slag formers. Zinc is mostly found on the rim of ejected particles where a gradual transition of zinc oxide to zinc ferrite to iron oxide is found. At sampling temperatures of between 800 and 1000°C most of the zinc had already condensed.
Transformation behaviour of the high temperature martensitic steels with 8 – 14% chromium
Authors: Finkler Helmut , Schirra Manfred 
Published: December 2016

Comprehensive development work on martensitic steels belonging to the so‐called 12% Cr steel group were performed at the Institute for Materials Research (IMF) of Forschungszentrum Karlsruhe on martensitic steels, the so‐called 12% Cr steel group, in order to meet the various requirements in nuclear and conventional energy technology. The transformation characteristics of 29 different grades of steel and 38 heats have been determined and continuous cooling transformation (CCT) diagrams have been prepared. The diagrams are first described by groups of subjects in a chronological order because the change in the chemical composition cannot be correlated in all cases with the change in transformation behaviour.The quenching hardness can be satisfactorily described as a function of the C+N content if, taking into account the Nb, Zr, Ta, Hf fractions, a common effectiveness factor is calculated. This effectiveness factor is also integrated in the calculation of the Ms point by modifying accordingly the equation proposed by Steven and Haynes for low‐alloy steels and supplemented by the summands for V and W. An equation is introduced for the calculation of the critical cooling rate for pearlite transformation which takes into account the special influence exerted by elements Cr, V, Mo, W, Ge. The comparison between calculated and measured values for Ms and Vcrit is satisfactory, except for some steels.
Carbon or nitrogen alloyed quenched and tempered stainless steels ‐ a comparative study
Authors: Berns Hans , Ehrhardt Rüdiger 
Published: December 2016

Some conventional stainless quenched and tempered steel grades were modified by substituting nitrogen for carbon and by variing the contents of chromium, molybdenum and nickel. Results of a comparative study of carbon and nitrogen steels are presented in a wide range of tempering temperatures.In nickelmartensitic steels nickel can be partially substituted by nitrogen without harming the properties. Due to their finer microstructure nitrogen steels with 15‐17 %Cr, 2 %Ni and 0.2 %N, at the same strength level, offer higher toughness and better corrosion resistance than the respective conventional steel X20 CrNi 17 2.
The influence of nitrogen and orientation on the rolling deformation mechanisms of austenitic single crystals
Authors: Akdut Nuri , Keichel Jörg , Foct Jacques 
Published: December 2016

The effect of nitrogen content and initial orientation on the deformation mechanisms of austenitic single crystals was investigated. From a nitrogen alloyed and a nitrogen free single crystal two initial orientations were cut out and cold rolled up to 90% thickness reduction, the corresponding {111} pole figures were measured and the slip traces were analyzed from the longitudinal section.In one of the nitrogen alloyed austenitic single crystals massive microcrack formation was observed. This observation was discussed in terms of the planarity of slip caused by the interstitially solved alloying element nitrogen. Nitrogen has a strong affinity to dislocations and thus alters the slip character from homogeneous to planar and the slip distribution from single slip to coarse slip. The present investigation proves that the coarse planar slip caused by the alloying element nitrogen in dependency of the initial orientation is responsible for the observed crack formation during rolling. The planarity of slip is also reflected in the measured pole figures. The {111} poles of the nitrogen alloyed single crystals show less scattering and higher maximum intensities than the poles of the nitrogen free single crystals. The differences were attributed to the influence of the nitrogen content on deformation mechanisms.
Chemical potentials of oxygen for three‐phase assemblages of CaSiO3(s) + Ca3Si2O7(s) + {CaO + SiO2 + FexO} melt and Ca3Si2O7(s) + Ca2SiO4(s) + {CaO + SiO2 + FexO} melt
Authors: Take‐uchi Kotaro , E‐naka Takashi , Kon‐no Norimitsu , Hosotani Yozo , Orimoto Takashi , Iwase Masanori 
Published: December 2016

By employing an electrochemical technique involving stabilized zirconia as solid electrolyte and Mo + MoO2 mixture as reference electrode, the equilibrium oxygen partial pressures for three‐phase assemblages of CaSiO3(s) + Ca3Si2O7(s) + {CaO + SiO2 + FexO} melt and Ca3Si2O7(s) + Ca2SiO4(s) + {CaO + SiO2 + FexO} melt were determined as:‐ log {PO2 (CS + C3S2 + L)/bar} = ‐ 3.22 13000/(T/K) ± 0.05‐ log {PO2 (C3S2 + C2S + L)/bar} = ‐ 0.92 16400/ (T/K) ± 0.04.respectively, where CS, C3S2 and C2S indicate CaSiO3(s), Ca3Si2O7(s). and Ca2SiO4(s), respectively.
A study on weldability of zinc‐coated steel sheets in lap joint configuration
Authors: El‐Batahgy Abdel‐Monem 
Published: December 2016

The weldability of Zn‐coated steel sheets 0.7 mm thick was investigated using resistance spot welding process. The effect of welding current, welding time and holding time on weld nugget characteristics, microstructure, and mechanical properties was discussed. Then, the possibility of replacing this welding process with laser beam welding was outlined. In this respect, quality of weld joints as a function of zinc removal by grinding prior to welding was evaluated.It is found that resistance spot welding current and time are the most significant parameters in affecting both expulsion and Zn‐induced porosity. Expulsion was avoided and Zn‐induced porosity was reduced with the decrease in welding current and/or welding time. Zn‐induced porosity was completely eliminated by zinc‐removal by grinding prior to welding. The best weld joint concerning nugget characteristics, soundness and tensile shear strength was obtained using welding current of 10 kA, weld cycle of 20, holding cycle of 18.Unlike resistance spot welds, high quality of CO2 laser welds free from Zn‐induced porosity could be made without zinc removal by grinding before welding.
Water spray cooling of stainless and C‐Mn steel
Authors: Olden Vigdis , Raudenský Miroslav , Onsrud Kristin , Hummel Wolfgang 
Published: December 2016

This paper describes laboratory cooling experiments of C‐Mn and stainless steel with a water/air nozzle. Experiments included use of both the steady state and the transient experimental method. The heat transfer coefficient was calculated both analytically and by a numerical method.The heat transfer coefficient was evaluated as a function of steel surface temperature, water flux, material and water/air flow.It was found that by increasing the water flux the heat transfer coefficient also increased. The Leidenfrost point was shifted to higher temperatures. Increasing air flow was also found to increase the heat transfer coefficient. Maximum heat transfer coefficient was twice as large for the C‐Mn steel as for the stainless steel.Comparison of the steady state and transient experimental method showed good agreement in the temperature range 200 – 500°C, and with a water flux of 2I/m2s. Above 500°C it was difficult to obtain stable conditions for the steady state experiments.
Quantification of precipitates in advanced creep resistant 9‐12% Cr steels
Authors: Hofer Peter , Cerjak Horst , Schaffernak Bernhard , Warbichler Peter 
Published: December 2016

In this paper a procedure is introduced for the quantification of precipitates appearing in 9‐12°Cr‐steels. Results gained from conventional transmission electron microscopic (TEM) investigations are compared with results from energy filtering transmission electron microscopic (EFTEM) investigations. The study was performed on a creep rupture specimen of the cast material G‐X12CrMoWVNbN10‐1‐1 exposed at 600°C and ruptured after 33000 h. The size distribution of M23C6 carbides, MX phase and Laves phase were measured for both the un‐stressed head and the stressed shank (gauge length) part of the investigated specimen. In particular, problems and sources of uncertainty concerning the quantitative determination of particle parameters in this type of steel are discussed.It is shown that quantification of the MX‐particles by means of TEM bright field images is hardly possible. The size distributions of M23C6 carbides and MX phase overlap significantly which makes a separation based only on their size nearly impossible. Only Laves phase occupies a different size range. The difference between the size distributions of head and shank is pronounced only for M23C6 carbides. The measured particle distributions obey more closely a log‐normal distribution rather than a normal distribution.
Control of inclusions in a resulphurised steel
Authors: Mapelli Carlo , Nicodemi Walter , Vedani Maurizio , Zoppi Alessio 
Published: December 2016

The formation of non‐metallic endogenous inclusions in ladle‐furnace treatment of a resulphurised C‐Mn Al‐killed steel was investigated. A model based on equilibrium reactions and using as input data compositions and temperatures measured at various stages of secondary steelmaking was developed and applied to different routine and experimental heats.Microstructural analyses were carried out on samples systematically extracted from ladle and from tundish. Detailed characterisation of inclusion morphology and composition was carried out to investigate their properties in the present resulphurised steel and to evaluate reactions taking place during different phases of ladle treatment. The experimental results were also used to validate the theoretical model. A good agreement between predicted concentrations of inclusions and experimentally measured values was obtained.
Combined blowing with three ‐ hole lance in a sidewall blowing converter
Authors: Juhani Fabritius Timo Matti , Mure Petri Tapani , Kupari Pentti Antero , Juntunen Veikko Antero , Härkki Jouko Juhani 
Published: December 2016

Traditionally, in stainless steelmaking converters, oxygen has been blown by a one‐hole lance (1 HL) and sidewall tuyères. In order to reduce the tap‐to‐tap time, the multi‐hole lance has been used for oxygen blowing. The aim of this work was to develop blowing practise for a multi‐hole lance to reduce the tap‐to‐tap time and minimise metal splashing and spitting in the sidewall blowing converter (chromium converter). In the chromium converter the chemical energy of liquid ferrochrome (which contains 4 % silicon and 7 % carbon) is utilised for scrap melting by oxidising the silicon and the part of carbon.The research has been made by a dynamically scaled water model and full‐scale converter. Used parameters were the gas flowrate from sidewall tuyères and lance, lance height, charge weight and position of multi‐hole lance. Splashing has been measured during blowing from walls (splashing) and mouth of the converter model (spitting). The model tests indicated less splashing and spitting by the three‐hole lance (3 HL) than traditional 1 HL. The 1 HL caused strong skulling of the converter cone. By 3 HL blowing the position of the lance has a remarkable effect on the direction and the amount of splashing and lance life. Because of hot metal‐slag splashes, the life time of the 3 HL was halved by position 1 (compared to 1 HL). With the lance position 2 the splashing decreased by approx. 50% in model tests and lance life time increased by ~ 50% (compared to 1 HL) in the full‐scale converter. The model agreed well with the full‐scale converter. According to the process tests, the nominal productivity of the chromium converter has increased 15 % and depending on the refining practise and the silicon content of ferrochromium the lining life has increased 20 ‐ 30 %. In the future the multi‐hole lance will be tested in the AOD vessel.
Celtic steel – an evaluation of depot finds
Authors: Preßlinger Hubert , Mayr Michael 
Published: December 2016

In the course of archaeological excavations on the Gründberg in Linz/Austria, several depots containing a total of 45 steel objects were discovered. These depots had been set up around 100 before Christ (BC). 25 objects were used to take samples for metallographic and microanalytical investigations.In the exercise of his trade, the Celtic smith could resort to different steel grades: non‐alloyed, carbon alloyed, phosphorus alloyed. The technique applied was that of fire‐forging single pieces of steel ‐ which had previously been widened by hammering – to give flat bars showing a multi‐layer structure.For workpieces with special requirements with regard both to hardness and to toughness, a number of carefully selected flat bars with differing contents of alloying metals were bonded by forge welding, which produced a compound material. Hardening by cold working as well as by torquing was already known to these Celtic craftsmen. To obtain tools with a hard edge and a tough core, cementation was used.
Detailed study of the transformation mechanisms in ferrous TRIP aided steels
Authors: Iung Thierry , Drillet Josée , Couturier Audrey , Olier Christopher 
Published: December 2016

Development of TRIP aided ferrous alloys is one answer to the demand for weight decrease in the automotive industry. The microstructure of hot rolled and cold rolled TRIP steels is quite complex and the optimisation of such steel products requires a detailed understanding of the mechanisms of phase transformation, during thermomechanical treatment as well as during mechanical testing or metal forming.We present in this paper the results obtained at Irsid concerning the study of austenite stabilisation through bainitic transformation during thermal treatment and its transformation into martensite during mechanical testing.First of all, the characterisation methods are presented. An effort has to be put on this point due to the refinement of the microstructure of TRIP steels, especially the size of austenite and martensite islands. Carbon replicas for the observation by means of transmission electron microscopy (TEM) are used to analyse the morphological features of the microstructure ‐ nature of the constituents, size and shape ‐ and the composition of cementite particles present in the steels. The mean value for this carbon content in retained austenite is deduced from X‐ray diffraction measurements.Then the kinetics of bainitic transformation are discussed as well as cementite precipitation. The typical composition of the steel studied is 0.5 % C, 1.5 % Mn. The use of 0.5 % C steels facilitates the study of bainitic transformation by avoiding the ferrite formation usually occurring in TRIP steels. Cementite nucleation appears at the ferrite/austenite interface without any partitionning of substitutional elements. To satisfy thermodynamic equilibrium at the interface, the silicon content on the cementite side is very low and high on the austenite side. Then, carbon diffusion towards austenite is delayed and, as a consequence, cementite growth is also delayed. As the diffusion kinetics are low at 400 °C, cementite keeps this “non partitioned” composition, even after 3 hours holding. At 500 °C, diffusion kinetics are higher and cementite composition approaches that predicted by equilibrium.Finally, the stability of retained austenite during mechanical testing is studied. Before and after mechanical testing the morphological characteristics of the microstructure (austenite island size and elongation) are analysed by TEM replicas and image analysis. There is a high density of very small austenite islands but they represent only a small fraction of the total retained austenite. These results confirm and quantify the size effect on austenite stabilisation during deformation.
Development and characterization of high strength impact resistant Fe‐Mn‐(Al‐, Si) TRIP/TWIP steels
Authors: Brüx Udo , Frommeyer Georg , Grässel Oliver , Meyer Lothar Werner , Weise Andrea 
Published: December 2016

Iron manganese steels with Mn mass contents of 15 to 30 % exhibit microstructural related superior ductility and extraordinary strengthening behaviour during plastic deformation, which strongly depends on the Mn content. This influences the austenite stability and stacking fault energy γfcc and shows a great impact on the microstructure to be developed under certain stress state or during severe plastic deformation. At medium Mn mass contents (15 to 20 %) the martensitic γ‐ε‐ά phase transformation plays an important role in the deformation mechanisms of the TRIP effect in addition to dislocation glide. With Increasing Mn mass content large elongation is favoured by intensive twinning formation. The mechanical properties of plain iron manganese alloys are strongly influenced by the alloying elements, Al and Si. Alloying with Al Increases the stacking fault energy and therefore strongly suppresses the martensitic γ‐ε transformation, while Si sustains the γ‐ε transformation by decreasing the stacking fault energy γfcc. The γ‐ε phase transformation takes place in Fe‐Mn‐X alloys with γfcc ≤ 20 mJm−2.The developed light weight high manganese TRIP and TWIP (twinning induced plasticity) steels exhibit high ultimate tensile strength (600 to 1100 MPa) and extremely large elongation of 60 to 95 % even at high strain rates of έ = 103 s−1.Particularly due to the advanced specific energy absorption of TRIP and TWIP steels compared to conventional deep drawing steels high dynamic tensile and compression tests were carried out in order to investigate the change in the microstructure under near crash conditions. Tensile and compression tests of iron manganese alloys with varying Mn content were performed at different temperatures and strain rates. The resulting formation of γ twins, ά‐ and ε martensite by plastic deformation was analysed by optical microscopy and X‐ray diffraction. The deep drawing and stretch forming behaviour at varying deformation rates were determined by performing cupping tests and digitalised stress‐strain‐analysis.