The Experts below are selected from a list of 2898 Experts worldwide ranked by ideXlab platform

Lauren B. Cooper - One of the best experts on this subject based on the ideXlab platform.

  • Global variations in H2O/Ce: 1. Slab Surface temperatures beneath volcanic arcs
    Geochemistry Geophysics Geosystems, 2012
    Co-Authors: Lauren B. Cooper, D. M. Ruscitto, Terry Plank, Paul J. Wallace, E. M. Syracuse, Craig E. Manning
    Abstract:

    [1] We have calculated Slab fluid temperatures for 51 volcanoes in 10 subduction zones using the newly developed H2O/Ce thermometer. The Slab fluid compositions were calculated from arc eruptives, using melt inclusion-based H2O contents, and were corrected for background mantle contributions. The temperatures, adjusted to h, the vertical depth to the Slab beneath the volcanic arc, range from ∼730 to 900°C and agree well (within 30°C on average for each arc) with sub-arc Slab Surface temperatures predicted by recent thermal models. The coherence between Slab model and Surface observation implies predominantly vertical transport of fluids within the mantle wedge. Slab Surface temperatures are well reconciled with the thermal parameter (the product of Slab age and vertical descent rate) andh. Arcs with shallow h (∼80 to 100 km) yield a larger range in Slab Surface temperature (up to ∼200°C between volcanoes) and more variable magma compositions than arcs with greater h (∼120 to 180 km). This diversity is consistent with coupling of the subducting Slab and mantle wedge, and subsequent rapid Slab heating, at ∼80 km. Slab Surface temperatures at or warmer than the H2O-saturated solidus suggest that melting at the Slab Surface is common beneath volcanic arcs. Our results imply that hydrous melts or solute-rich supercritical fluids, and not H2O-rich aqueous fluids, are thus the agents of mass transport to the mantle wedge.

  • global variations in h2o ce 1 Slab Surface temperatures beneath volcanic arcs
    Geochemistry Geophysics Geosystems, 2012
    Co-Authors: Lauren B. Cooper, D. M. Ruscitto, Terry Plank, Paul J. Wallace, E. M. Syracuse, Craig E. Manning
    Abstract:

    [1] We have calculated Slab fluid temperatures for 51 volcanoes in 10 subduction zones using the newly developed H2O/Ce thermometer. The Slab fluid compositions were calculated from arc eruptives, using melt inclusion-based H2O contents, and were corrected for background mantle contributions. The temperatures, adjusted to h, the vertical depth to the Slab beneath the volcanic arc, range from ∼730 to 900°C and agree well (within 30°C on average for each arc) with sub-arc Slab Surface temperatures predicted by recent thermal models. The coherence between Slab model and Surface observation implies predominantly vertical transport of fluids within the mantle wedge. Slab Surface temperatures are well reconciled with the thermal parameter (the product of Slab age and vertical descent rate) andh. Arcs with shallow h (∼80 to 100 km) yield a larger range in Slab Surface temperature (up to ∼200°C between volcanoes) and more variable magma compositions than arcs with greater h (∼120 to 180 km). This diversity is consistent with coupling of the subducting Slab and mantle wedge, and subsequent rapid Slab heating, at ∼80 km. Slab Surface temperatures at or warmer than the H2O-saturated solidus suggest that melting at the Slab Surface is common beneath volcanic arcs. Our results imply that hydrous melts or solute-rich supercritical fluids, and not H2O-rich aqueous fluids, are thus the agents of mass transport to the mantle wedge.

  • Emerging geothermometers for estimating Slab Surface temperatures
    Nature Geoscience, 2009
    Co-Authors: Terry Plank, Lauren B. Cooper, Craig E. Manning
    Abstract:

    Slab fluids drive mantle melting and return ocean water to the Earth's Surface through arc volcanism. New ways of estimating the temperature of Slab fluids indicate relatively hot conditions, and hint at a shallow and fast return path for ocean water.

Craig E. Manning - One of the best experts on this subject based on the ideXlab platform.

  • Global variations in H2O/Ce: 1. Slab Surface temperatures beneath volcanic arcs
    Geochemistry Geophysics Geosystems, 2012
    Co-Authors: Lauren B. Cooper, D. M. Ruscitto, Terry Plank, Paul J. Wallace, E. M. Syracuse, Craig E. Manning
    Abstract:

    [1] We have calculated Slab fluid temperatures for 51 volcanoes in 10 subduction zones using the newly developed H2O/Ce thermometer. The Slab fluid compositions were calculated from arc eruptives, using melt inclusion-based H2O contents, and were corrected for background mantle contributions. The temperatures, adjusted to h, the vertical depth to the Slab beneath the volcanic arc, range from ∼730 to 900°C and agree well (within 30°C on average for each arc) with sub-arc Slab Surface temperatures predicted by recent thermal models. The coherence between Slab model and Surface observation implies predominantly vertical transport of fluids within the mantle wedge. Slab Surface temperatures are well reconciled with the thermal parameter (the product of Slab age and vertical descent rate) andh. Arcs with shallow h (∼80 to 100 km) yield a larger range in Slab Surface temperature (up to ∼200°C between volcanoes) and more variable magma compositions than arcs with greater h (∼120 to 180 km). This diversity is consistent with coupling of the subducting Slab and mantle wedge, and subsequent rapid Slab heating, at ∼80 km. Slab Surface temperatures at or warmer than the H2O-saturated solidus suggest that melting at the Slab Surface is common beneath volcanic arcs. Our results imply that hydrous melts or solute-rich supercritical fluids, and not H2O-rich aqueous fluids, are thus the agents of mass transport to the mantle wedge.

  • global variations in h2o ce 1 Slab Surface temperatures beneath volcanic arcs
    Geochemistry Geophysics Geosystems, 2012
    Co-Authors: Lauren B. Cooper, D. M. Ruscitto, Terry Plank, Paul J. Wallace, E. M. Syracuse, Craig E. Manning
    Abstract:

    [1] We have calculated Slab fluid temperatures for 51 volcanoes in 10 subduction zones using the newly developed H2O/Ce thermometer. The Slab fluid compositions were calculated from arc eruptives, using melt inclusion-based H2O contents, and were corrected for background mantle contributions. The temperatures, adjusted to h, the vertical depth to the Slab beneath the volcanic arc, range from ∼730 to 900°C and agree well (within 30°C on average for each arc) with sub-arc Slab Surface temperatures predicted by recent thermal models. The coherence between Slab model and Surface observation implies predominantly vertical transport of fluids within the mantle wedge. Slab Surface temperatures are well reconciled with the thermal parameter (the product of Slab age and vertical descent rate) andh. Arcs with shallow h (∼80 to 100 km) yield a larger range in Slab Surface temperature (up to ∼200°C between volcanoes) and more variable magma compositions than arcs with greater h (∼120 to 180 km). This diversity is consistent with coupling of the subducting Slab and mantle wedge, and subsequent rapid Slab heating, at ∼80 km. Slab Surface temperatures at or warmer than the H2O-saturated solidus suggest that melting at the Slab Surface is common beneath volcanic arcs. Our results imply that hydrous melts or solute-rich supercritical fluids, and not H2O-rich aqueous fluids, are thus the agents of mass transport to the mantle wedge.

  • Emerging geothermometers for estimating Slab Surface temperatures
    Nature Geoscience, 2009
    Co-Authors: Terry Plank, Lauren B. Cooper, Craig E. Manning
    Abstract:

    Slab fluids drive mantle melting and return ocean water to the Earth's Surface through arc volcanism. New ways of estimating the temperature of Slab fluids indicate relatively hot conditions, and hint at a shallow and fast return path for ocean water.

Toru Kato - One of the best experts on this subject based on the ideXlab platform.

  • Prevention of Slab Surface transverse cracking at Kashima n° 2 caster with Surface Structure Control (SSC) cooling
    Revue de Métallurgie, 2006
    Co-Authors: N. Baba, K. Ohta, Y. Ito, Toru Kato
    Abstract:

    Transverse cracking may occur in high strength low alloy CC Slabs. This phenomenon is associated to a hot ductility trough resulting from intergranular ferrite that forms at the beginning of the γ -α transformation. Sumitomo has developed a hot tensile machine and a unique Slab Surface microstructure control process to improve hot ductility. The process based on controlled accelerated secondary cooling has been successfully implemented on Kashima n°2 caster.

  • prevention of Slab Surface transverse cracking at kashima n 2 caster with Surface structure control ssc cooling
    Revue De Metallurgie-cahiers D Informations Techniques, 2006
    Co-Authors: N. Baba, K. Ohta, Toru Kato
    Abstract:

    Transverse cracking may occur in high strength low alloy CC Slabs. This phenomenon is associated to a hot ductility trough resulting from intergranular ferrite that forms at the beginning of the γ - α transformation. Sumitomo has developed a hot tensile machine and a unique Slab Surface microstructure control process to improve hot ductility. The process based on controlled accelerated secondary cooling has been successfully implemented on Kashima n°2 caster.

  • prevention of Slab Surface transverse cracking by microstructure control
    Isij International, 2003
    Co-Authors: Toru Kato, Masayuki Kawamoto, Akihiro Yamanaka, Tadao Watanabe
    Abstract:

    Slab Surface transverse cracking is well known to be induced by strain concentration at film-like primary ferrite, i.e. allotriomorphs of ferrite formed along the austenite grain boundaries. In the present study, a new concept for the prevention of transverse cracking by means of microstructure control at continuous casting strand is examined. Three kinds of examinations in charge of each objective were conducted; (a) ingot cooling tests for microstructure control with secondary cooling; (b) hot tensile tests for hot ductility with the microstructure; and (c) continuous casting tests for cracking susceptibility on continuously cast Slab. Results obtained are concluded as follows. (1) Slab Surface microstructure could be controlled by secondary cooling condition. Surface structure control (SSC) cooling, providing intensive cooling until less than A 3 transformation temperature just below mold and subsequently reheated up to 1 250 K in secondary cooling, brings film-like ferrite free structure. (2) Hot tensile tests subsequent to in-situ remelting and solidification prove that hot ductility is much improved and ductility trough almost disappeared with that microstructure control. The results also confirm that in-situ remelting of specimen is indispensable on the hot tensile test to evaluate the effect of microstructure on susceptibility to transverse cracking. (3) Continuous casting test confirms that susceptibility to transverse cracking could be alleviated with this microstructure control. (4) The prevention of transverse cracking and microstructure control is a result of uniform fine precipitates dispersion, such as (Ti, Nb)(C, N), according to SSC cooling.

Margita Longauerová - One of the best experts on this subject based on the ideXlab platform.

  • Local Notch Toughness of Slab Surface Zone in ULC/IF and HSLA Steels
    Key Engineering Materials, 2015
    Co-Authors: Margita Longauerová, Maria Hurakova, Pavel Bekeč, Svätoboj Longauer, Mária Fedorová, Jana Konrádyová
    Abstract:

    The aim of this work was to analyze changes in local toughness KCV using Charpy V-notch impact tests in the Slab Surface zone in relation to the microstructure in ULC/ IF steel and TiNb HSLA steel. Marked heterogeneity in KCV values was confirmed in the Surface zone across the width of transitional Slabs. Distinct local differences in notch toughness across the Slab width were found to be linked primarily with changes in ferrite grain size. Low KCV values in the analyzed steels were linked with coarse grain structure, while much finer ferrite structure was identified in tough samples. The heterogeneity of KCV vales in the analyzed steels may be influenced by differences in thickness of the fine-grain Slab Surface zone, and by the presence of tertial cementite and (in HSLA steel) of pearlite as well.

  • Effect of Sample Thickness on Slab Surface Zone Toughness in IF and Microalloyed Steels
    Key Engineering Materials, 2015
    Co-Authors: Margita Longauerová, Maria Hurakova, Pavel Bekeč, Svätoboj Longauer, Mária Fedorová, Jaroslav Duška, Jana Konrádyová
    Abstract:

    The aim of this work was to analyze the effect of sample thickness on toughness of the Slab Surface zone at ambient temperature in IF and microalloy steels. Transitional Slabs with different pulling rates at the start and the end of the Slab were used as well as Slabs with standard pulling rates. Samples of standard size 10x10x55 mm and also non-standard size 5x10x55 mm were used for Charpy impact testing. It was confirmed that higher toughness values were found in thin non-standard size samples (5x10x55 mm), or more precisely for a larger portion of non-standard samples with toughness values higher than 50 J.cm-2. Using non-standard size samples confirmed the distinct stability of toughness values, as well as their smaller spread between minimum and maximum values. The transitional Slabs had very distinct and non-uniform spread of toughness values across the Slab width. This suggests greatly deteriorated quality of these Slabs. During stable casting of TiNb microalloyed steel at the standard conventional higher Slab pulling rate, uniform toughness was confirmed across the whole Slab width in both sample types.

  • Influence of Casting Rate on TiNb Microalloyed Steel Slab Surface Area Microstructure
    Materials Science Forum, 2014
    Co-Authors: Pavel Bekeč, Margita Longauerová, Marek Vojtko
    Abstract:

    Two Slabs of Ti-Nb microalloyed steel were analysed in this work. The first Slab was transitional with the initial pulling rate 0.43 m.min-1 and the final pulling rate 0.9 m.min-1. The second Slab was cast at the real production pulling rate 1.03 m.min-1. The presence of larger amounts of oscillation marks was observed on the first Slab at both pulling rates. The second Slab showed no oscillation marks. At the lowest pulling rate, cracks were discovered below the Slab Surface, often below oscillation marks. Cracks were seldom observed at pulling rate 0.9 m.min-1. In the first Slab, especially at the low pulling rate, the presence of cracks and pores was found. Pores were observed often with clusters of aluminum oxides. The microstructure of the Slab Surface zone was characterised by heterogeneity of ferrite grain sizes at all three pulling rates. This heterogeneity was manifested mainly in the marginal cut-outs at all pulling rates. In the marginal cut-outs the microstructure was granulometrically finer at all three pulling rates than in the central cut-outs. Non-equilibrium microstructure in the marginal cut-outs was also observed.

  • INFLUENCE OF COOLING RATE ON TiNb MICROALLOYED STEEL Slab Surface ZONE FRACTURE MORPHOLOGY
    Acta Metallurgica Slovaca - Conference, 2013
    Co-Authors: Margita Longauerová, Pavel Bekeč, Svätoboj Longauer, Marek Vojtko, Pavol Marek
    Abstract:

    The aim of this work was to analyze the influence of technology on the morphology of fractures and Charpy impact toughness in the TiNb microalloyed steel Slab Surface zone. The Slab was made by continuous casting using different cooling rates  in the secondary cooling zone (2 cooling rates were selected for testing) and 2 Slab pulling rates 0.5 m/min and 0.8 m/min. It turned out that, with a higher Slab pulling rate for both cooling rates applied, the impact toughness was generally lower than that with the slow pulling rate. Microstructure analyses showed the composition of the Surface zone was formed by ferrite and pearlite. Coarser ferrite was seen in the Surface zone with the higher Slab pulling rate and higher cooling rate in the secondary cooling zone. The Surface zone microstructure was polyedric for the lower cooling rate and sporadically nonpolyedric with needle-like, or acicular ferrite for faster cooling. Brittle fracture test pieces showed fracture Surfaces with transcrystalline cleavage facets (TCF) regardless of the applied cooling rate. With lower cooling rates, smooth facets of intercrystalline decohesion (FID) were identified too, but at less than 0.1%. With faster cooling they showed up in a few isolated cases only.  The occurrence of dimpled transcrystalline ductile fractures (DTDF) was generally low. It was confirmed that the morphology of forced fractures was influenced by the cooling rate via the produced microstructure.  The embrittlement of the tested samples was assisted by clusters and single particles. They were identified using EDX as based on Al, or combined with Ti, Nb nitrides, or carbide and sulphide eutectics, or inclusions ordered in rows in the ferrite network. Since the occurrence of intercrystalline fractures was low with faster cooling and high Slab pulling rate, distinctive suppression of segregation can be assumed for this technology, if compared to slow cooling and low Slab pulling rate.

Xianghua Liu - One of the best experts on this subject based on the ideXlab platform.

  • Longitudinal crack on Slab Surface at straightening stage during continuous casting using finite element method
    Journal of Central South University of Technology, 2010
    Co-Authors: Xianghua Liu
    Abstract:

    Deformation behavior of Slab at the straightening stage during continuous casting was simulated by the explicit dynamic finite element method, and the stress distribution along the width direction of the Slab and its change regularity at Slab center during continuous casting were obtained. The influence of distribution and change of stress on the propagation of longitudinal cracks on Slab Surface was discussed. The results show that the tensional stress appears on Slab Surface at the inner arc side and the compressive stress appears on Slab Surface at the outer arc side at stages 6–8 in straightening zone during continuous casting. Longitudinal cracks generally appear on Slab top Surface and do not appear on Slab bottom Surface, which are also observed in industry.

  • Analysis of vibration of crystallizer on stress distribution of Slab during continuous casting using FEM
    Journal of Iron and Steel Research, 2010
    Co-Authors: Yue-xin Wang, Xianghua Liu
    Abstract:

    The vibrating process of crystallizer during continuous casting was carried out by using the finite element method,and the stresses near Slab Surface at different stages were analyzed under various taper ratios of crystallizer,friction coefficients between crystallizer and Slab,pulling speeds of Slab,and Slab widths.Results show that the stress concentration appears in the Slab Surface near the tail end of crystallizer.The maximum stress in Slab Surface increases with decreasing the taper ratio of crystallizer,and with increasing the Slab width.And influence of the pulling speed of Slab and the friction coefficient between Slab and crystallizer on the maximum stress in Slab is slight.It is of significant for analyzing and understanding the initiation of vibration marks on Slab Surface and the fraction and wear of crystallizer.

  • Numerical Analysis of Transversal Crack on Slab Corner in Straightening During Continuous Casting
    Journal of Iron and Steel Research, 2009
    Co-Authors: Yue-xin Wang, Xianghua Liu
    Abstract:

    The transversal cracks might appear on Slab corner positions during continuous casting,which severely affect the quality and quantity of products.The behavior of Slab in the straightening period during continuous casting,and the stress distribution on Slab Surface and the change regularity of stress on Slab corner were obtained by dominant kinetics finite element method,finally the influence of stress distribution on Slab on the initiation of transversal cracks on Slab corner was discussed.Results show that the tensile stress appears on Slab Surface of inner arc side when the Slab passes through the stage 6-8 during continuous casting.The research results are good for guiding the production.

  • Research on behavior of Slab Surface defects in forward slip zone during V-H rolling process
    Materials Science Forum, 2008
    Co-Authors: Xianghua Liu, Liqing Chen
    Abstract:

    Behavior of the transversal crack and the longitudinal crack on Slab Surface during V-H rolling was simulated by the FEM. The contact pressure on crack Surfaces and the crack-tip stress change rules during rolling were analyzed. Results show that the contact pressure on crack Surfaces decreases and the tensile stress appears at crack tip in the zone of slippage on the delivery side, which may make the cracks propagation. For the phenomenon, the stress distribution along rolling direction and along width direction in rolling are analyzed, and the influence of forward slip on the closure and growth of the Surface transversal crack and the Surface longitudinal crack are discussed. Results support some significant information for researching the behavior of the Slab Surface defects in rolling process.