How the EU project "Online Microstructure Analytics" advances inline sensing of microstructure during steel manufacturing

Weight savings in mobility and transport are mandatory in order to reduce CO 2 emissions and energy consumption. The steel industry offers weight saving solutions by a growing portfolio of Advanced High Strength Steel (AHSS) products. AHSS owe their strength to their largely refined and complex microstructures, containing multiple metallurgical phases. Optimal control of the thermo-mechanical processing of AHSS requires inline sensors for real-time monitoring of evolution and consistency of microstructure and material properties. To coordinate and accelerate European development activities in this domain, the project ¿Online Microstructure Analytics (OMA)¿ was established in 2019, constituting of a consortium of 14 specialised research organisations. The EU-funded OMA project, with a total budget exceeding 6 MEU, focuses on inline sensing techniques to monitor the consistency and homogeneity of microstructure, texture and mechanical properties for automotive steels and in particular for AHSS.This project has received funding from the Research Fund for Coal and Steel under grant agreement No 84729

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42\ub74% vs 44\ub72%; absolute difference \u20131\ub769 [\u20139\ub758 to 6\ub711] p=0\ub767; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5\u20138] vs 6 [5\u20138] cm H2O; p=0\ub70011). ICU mortality was higher in MICs than in HICs (30\ub75% vs 19\ub79%; p=0\ub70004; adjusted effect 16\ub741% [95% CI 9\ub752\u201323\ub752]; p<0\ub70001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0\ub780 [95% CI 0\ub775\u20130\ub786]; p<0\ub70001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status. Funding: No funding

Effect of Austenite Deformation on the Microstructure Evolution and Grain Refinement Under Accelerated Cooling Conditions

Although there has been much research regarding the effect of austenite deformation on accelerated cooled microstructures in microalloyed steels, there is still a lack of accurate data on boundary densities and effective grain sizes. Previous results observed from optical micrographs are not accurate enough, because, for displacive transformation products, a substantial part of the boundaries have disorientation angles below 15 deg. Therefore, in this research, a niobium microalloyed steel was used and electron backscattering diffraction mappings were performed on all of the transformed microstructures to obtain accurate results on boundary densities and grain refinement. It was found that with strain rising from 0 to 0.5, a transition from bainitic ferrite to acicular ferrite occurs and the effective grain size reduces from 5.7 to 3.1 μm. When further increasing strain from 0.5 to 0.7, dynamic recrystallization was triggered and postdynamic softening occurred during the accelerated cooling, leading to an inhomogeneous and coarse transformed microstructure. In the entire strain range, the density changes of boundaries with different disorientation angles are distinct, due to different boundary formation mechanisms. Finally, the controversial influence of austenite deformation on effective grain size of low-temperature transformation products was argued to be related to the differences in transformation conditions and final microstructures

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Aceros avanzados de alta resistencia de matriz bainítica: Estudio de la transformación de fase y de las relaciones entre procesamiento, microestructura y propiedades mecánicas.

Debido a la creciente exigencia de la industria automovilística por aligerar el peso del vehículo e incrementar la seguridad, han surgido nuevos grados de acero de alta resistencia. Los aceros bainíticos libres de carburos, por sus buenas propiedades mecánicas, son candidatos a formar parte de la tercera generación de aceros avanzados de alta resistencia. Este tipo de acero se produce principalmente en forma de chapa en líneas de recocido continuo o galvanizado, por lo que las diferentes variables del proceso influyen de manera notable, tanto sobre su microestructura final como en las propiedades mecánicas. Esta tesis se ha centrado en el estudio de dos aceros bajo carbono con matriz bainitica aleados respectivamente con silicio y cromo. En primer lugar, se han analizado las cinéticas de transformación de ambos aceros durante su permanencia en la región bainítica y se ha estudiado en detalle la evolución microestructural de ambos con las variables del ciclo térmico. Para llevar a cabo este estudio, se han realizado ensayos de dilatometría donde se ha variado la temperatura de austenización, la velocidad de enfriamiento y la temperatura y tiempo de mantenimiento en la región bainitica. Además, ha sido necesario desarrollar una metodología para la preparación metalográfica de las muestras y la cuantificación de las fases que componen la microestructura a través de diferentes técnicas (óptico, FEG-SEM, EBSD y rayos X). En segundo lugar, se han estudiado las propiedades mecánicas de estos aceros atendiendo a tres puntos. En el primero, se ha tenido en cuenta el comportamiento mecánico de cada uno de los microconstituyentes: bainita, martensita de bajo carbono, martensita de alto carbono y austenita retenida. En concreto, se ha medido la dureza a través del empleo de la técnica de nanoindentación y se ha relacionado esta propiedad con las variables del proceso.Con el objeto de profundizar en las relaciones microestructura-proceso-propiedades mecánicas, se han realizado una serie de ensayos de tracción sobre las muestras extraídas de chapas recocidas en el simulador de recocido vertical que posee el CEIT. Estos ensayos, junto a otros ensayos incluidos dentro del proyecto Baseform, proyecto en el que se enmarca esta tesis, han dado lugar a una gran variabilidad de limite elástico, resistencia a la tracción y elongaciones. Esto ha permitido realizar un análisis exhaustivo de las relaciones entre propiedades mecánicas, microestructura y procesamiento. Además de las propiedades a tracción, como tercer punto, se ha estudiado la conformabilidad. La baja conformabilidad en frio y los problemas de agrietamiento de borde de los aceros multifásicos son las principales desventajas que presentan los aceros multifásicos. Por ello, se busca de manera incesante el modo de evitar estos problemas e incrementar la conformabilidad. En este trabajo se han empleado los resultados de los ensayos de expansión de orificio (HET), obtenidos dentro del proyecto Baseform, con ellos se mide de forma indirecta la conformabilidad, con el objeto de relacionar esta propiedad con la microestructura y así mejorarla a través de la optimización de la microestructura. Con el objeto de profundizar en las relaciones microestructura-proceso-propiedades mecánicas, se han realizado una serie de ensayos de tracción sobre las muestras extraídas de chapas recocidas en el simulador de recocido vertical que posee el CEIT. Estos ensayos, junto a otros ensayos incluidos dentro del proyecto Baseform, proyecto en el que se enmarca esta tesis, han dado lugar a una gran variabilidad de limite elástico, resistencia a la tracción y elongaciones. Esto ha permitido realizar un análisis exhaustivo de las relaciones entre propiedades mecánicas, microestructura y procesamiento. Además de las propiedades a tracción, como tercer punto, se ha estudiado la conformabilidad. La baja conformabilidad en frio y los problemas de agrietamiento de borde de los aceros multifásicos son las principales desventajas que presentan los aceros multifásicos. Por ello, se busca de manera incesante el modo de evitar estos problemas e incrementar la conformabilidad. En este trabajo se han empleado los resultados de los ensayos de expansión de orificio (HET), obtenidos dentro del proyecto Baseform, con ellos se mide de forma indirecta la conformabilidad, con el objeto de relacionar esta propiedad con la microestructura y así mejorarla a través de la optimización de la microestructura.Por último, se han realizado ensayos de tracción sobre diferentes geometrías de probeta para estudiar cómo evoluciona la microestructura con la deformación y cómo y dónde se produce el daño en el acero con alto contenido en Si. Se ha analizado la evolución de la austenita retenida, afectada por el efecto TRIP (transformation induced plasticity) y de la matriz bainítica, tanto en la región de deformación uniforme como dentro de la zona de estricción. Además, se ha evaluado los lugares donde se originan las cavidades y como tiene lugar la fractura.New grades of high strength steels have emerged in response to the growing demand of the automobile industry to lighten the weight and increase the safety. Carbide free steels are candidates to be part of the third AHSS steels due to their good mechanical properties. They are produced in the form of sheet and in a continuous annealing or galvanized, therefore the process conditions have an important influence on the microstructure and mechanical properties. This dissertation is focused on the study of two low carbon steels with bainitic matrix, one alloyed with silicon and another with chromium. Firstly, phase transformation kinetics and microstructural evolution of both steels as function of the process conditions has been analysed. In order to perform this study, dilatometry tests have been performed varying the austenitization temperature, cooling rate and temperature and time in the bainitic region. It was necessary to develop a methodology for the sample preparation and phase quantification with several techniques (optical, FEG-SEM, EBSD, X-ray diffraction).Secondly, the mechanical properties of these steels have been studied according to three points. Firstly, mechanical properties, specifically, the hardness of the phases, which compound the microstructure: bainite, low carbon martensite, high carbon martensite and retained austenite has been measured and associated with the processing conditions. Nanoindentation technique has been used to carry out this study. In order to evaluate the relationship between the microstructure, process conditions and mechanical properties, several tensile tests were carried out on the samples extracted from annealed sheets in the vertical annealing simulator that CEIT has. These tests together with the tests included in the project Baseform, project in which this thesis is framed, have led to a great variability of yield strength, tensile strength and elongation. This has allowed an in-depth analysis of the relationships between mechanical properties, microstructure and processing. In addition, formability has been studied. The low cold-formability and the problem of edge cracking are the principal disadvantages of the multiphase steel. Thus, considerable attention has been paid to the improvement in these properties. In this work, hole expansion test (HET) have been performed, in which formability is measured in an indirect way. These results have been related with microstructure with the purpose of understand the relationship to improving the formability.Lastly, tensile tests on specimens with different geometries have been performed to study how the microstructure evolves with the strain and how and where the damage is produced in high silicon steel. The bainitic matrix and retained austenite evolution have been analysed in the uniform and necking region. Retained austenite is affected by the TRIP effect (Transformation Induced Plasticity). Furthermore, the preferred sites where voids are originated and how the fracture is has been evaluated

Non-destructive magnetic evaluation of microstructure and mechanical properties of advanced high-strength steels

13th EUROPEAN CONFERENCE ON NON-DESTRUCTIVE TESTING LISBOA - PORTUGALBecause of more demanding mechanical properties in sheet steel products in the automotive industry, the use of multi-phase steels, capable of complying with those mechanical requirements, has been growing along the last decades. The non-destructive characterization of these steel grades, therefore, has become an active research line worldwide. In the present work, the magnetic characterization by magnetic hysteresis BH loops of various strip samples of industrially cold rolled and annealed DP800 (dual phase) and CP800 (complex phase) steels at several positions with varying processing temperatures in the coil length has been performed. In addition, a detailed EBSD characterization of the samples has allowed determining the fraction of the various microconstituents, namely, ferrite, bainite, martensite and retained austenite. Finally, the mechanical characterization has been done through hardness and tensile tests on all the samples. All the results regarding these three aspects have been analysed carefully to extract likely relationships among them. Clear one-to-one linear correlations have been found between all these features, even though large variations in mechanical/magnetic properties and microstructures have been attained. Specifically, for volume fractions of bainite approximately between 15% to 75%, the yield and tensile strengths show a linear correlation with the coercive field, Hc. Thus, the coercive field may be a candidate to become a parameter for the prediction of the mechanical properties if a previous calibration is performed on these steel grades with multi-phase microstructures

Substructure development and damage initiation in a carbide-free bainitic steel upon tensile test

Carbide-free bainitic (CFB) steels belong to the family of advanced high strength steels (AHSS) that are struggling to become part of the third-generation steels to be marketed for the automotive industry. The combined effects of the bainitic matrix and the retained austenite confers a significant strength with a remarkable ductility to these steels. However, CFB steels usually show much more complex microstructures that also contain MA (Martensite–Austenite) phase and auto-tempered martensite (ATM). These phases may compromise the ductility of CFB steels. The present work analyzes the substructure evolution during tensile tests in the necking zone, and deepens into the void and crack formation mechanisms and their relationship with the local microstructure. The combination of FEG-SEM imaging, EBSD, and X-ray diffraction has been necessary to characterize the substructure development and damage initiation. The bainite matrix has shown great ductility through the generation of high angle grain boundaries and/or large orientation gradients around voids, which are usually found close to the bainite and MA/auto-tempered martensite interfaces or fragmenting the MA phase. Special attention has been paid to the stability of the retained austenite (RA) during the test, which may eventually be transformed into martensite (Transformation Induced Plasticity, or TRIP effect)