Vantaggi del riscaldamento ad induzione, nuove possibilità di efficienza e flessibilità per i laminatoi per prodotti lunghi

Alcune soluzioni impiantistiche che prevedono l’usodi sistemi di riscaldo ad induzione sono già di comuneapplicazione, ma hanno comunque un potenziale diulteriore miglioramento, altre sono tuttora oggetto disviluppo prototipale e potranno essere presto introdottesu scala industriale. Tra le più significative aree diapplicazione delle tecnologie di riscaldo ad induzione sievidenziano l’ottimizzazione del ciclo di riscaldo dellebillette, il controllo accurato del profilo termico della barranel treno di laminazione e il riscaldo selettivo nelle areedi trattamento e di finitura del prodotto. Questo articoloillustra alcune delle soluzioni progettate e applicate daSiemens in collaborazione con ABP GmbH.DISCUSSIONEIl mercato per prodotti lunghi è caratterizzato da una straordinariavarietà tecnica di dimensioni e forme, con unaproduzione su scala mondiale raddoppiata negli ultimi 10anni e soggetta a continue sfide tecnologiche riguardo airequisiti di qualità e ai costi di trasformazione. Nel futuroci si aspetta un’ulteriore leggera crescita dei volumi diproduzione, con un sempre più marcato spostamento diattenzione dai volumi di produzione ad obiettivi di qualitàed efficienza operativa.La catena di produzione dei prodotti lunghi è sempre piùesposta alle anomale fluttuazioni del costo del materialee dell’energia. Di conseguenza, per mantenere sufficientimargini operativi, i produttori devono necessariamenteinvestire in soluzioni volte ad ottimizzare i costi di trasformazionedel prodotto.Le sfide tecnologiche ed economiche nella produzionedei prodotti lunghi riguardano l’ottimizzazione energetica,l’impatto ambientale, il perfezionamento della qualità delprodotto as-rolled, la resa metallica di trasformazione ein generale la logistica di processo. Queste sfide portanoi produttori a ricercare soluzioni per linee di produzionecompatte, equipaggiate con gruppi di macchine di processoultra-efficienti che operano come veri e propri “centridi lavoro” gestiti da logiche di controllo intelligenti checonsentono ad esempio settaggi in auto-adattamento dinamico.È evidente che le varie tipologie di impianto per prodottilunghi hanno contenuti tecnologici a vari livelli e garantisconodiversi margini operativi in funzione di molti fattorilocali e globali. Ci sono settori basati su tecnologie moltoconsolidate ma che tuttavia possiedono ulteriori marginidi miglioramento nella performance e nell’efficienza operativa,settori con ampie opportunità di espansione tecnologicae altri invece con livelli di produzione saturi e ridottimargini di intervento. In questo scenario di continua sfidatecnico-economica, un significativo contributo può veniredalle competenze e dalle applicazioni di aree industrialicontigue a quelle della laminazione. Il modello di innova-Il presente articolo illustra alcune soluzioni di riscaldo ad induzione per laminatoi. Le tecnologie di riscaldo adinduzione hanno diverse opportunità di applicazione nei laminatoi per prodotti lunghi. Le evoluzioni attuali deisistemi di controllo di potenza e dell’automazione di processo, integrate con sempre più accurati modelli termometallurgici,offrono vantaggi operativi certi in termini di qualità del prodotto laminato, di efficienza, flessibilitàe compattezza dell’impianto

Previsione delle caratteristiche qualitative di prodotti laminati tramite definizione dei parametri termomeccanici di lavorazione: il sistema Promet 4.0

L’obiettivo del progetto di ricerca, del quale viene descritto in questa sede il prodotto finale, era la messa apunto di un metodo di previsione della microstruttura che, tenendo conto delle condizioni di laminazione eraffreddamento, fosse in grado di anticipare le principali caratteristiche meccaniche e microstrutturali dellaminato. Il modello è stato sviluppato partendo dalle conoscenze teoriche sviluppate dai molti ricercatori che sisono occupati di queste problematiche, e dall’esperienza accumulata nell’attività di progettazione di impianti.Al fine di consentire la massima flessibilità operativa all’utilizzatore, il software prevede che siano fornite lecondizioni operative di laminazione (riduzione per passata, temperatura, tempo intergabbia, temperatura dipreriscaldo, eventuale profilo di raffreddamento), e dispone di un database di oltre 100 acciai, contenente lecurve CCT e le proprietà meccaniche in relazione alla velocità di raffreddamento. Lo strumento fornisce lacurva CCT, opportunamente modificata per tener conto della microstruttura del laminando, con sovrimposta latraiettoria di raffreddamento impostata dall’operatore, nonché i dati microstrutturali e meccanici di interesseper quella determinata classe di acciai. Il software è stato validato tramite confronto diretto con le proprietà diprodotti laminati in condizioni controllate, ottenendo un’eccellente capacità previsionale.INTRODUZIONE:L’IMPORTANZA DEL CONTROLLO DELLE CONDIZIONIDI LAMINAZIONE NEI MODERNI IMPIANTILa temperatura, la velocità di deformazione e il raffreddamentosuccessivo alla laminazione possono determinare caratteristichetecnologiche tali da poter eliminare, in alcuni prodotti, successivicostosi trattamenti termici. Alla fine della laminazione ilpezzo lavorato ha una temperatura ancora molto alta, che dipendesia dall'impianto sia dai parametri di laminazione adottati.Le moderne tecnologie prevedono un controllo costante dellatemperatura nelle varie fasi del processo, incluso il raffreddamentofinale dopo l'ultima gabbia in presa, e dell'evoluzione delgrano austenico. Le fasi più interessanti del processo sono: a. laminazionea temperatura controllata nel treno sbozzatore e intermedio;b. raffreddamento ad acqua a monte e a valle dellegabbie di finitura; c. raffreddamento controllato su linee di evacuazione.Per i prodotti in barre vengono usati letti debitamente proporzionatiin lunghezza e larghezza, dove i prodotti, una volta scaricati,vengono traslati tramite appositi longheroni mobili eM. El Mehtedi, S. SpigarelliDipartimento di Ingegneria Industriale e Scienze Matematiche,Università Politecnica delle Marche, 60123 – Ancona (Italy)tel. +390712204746, fax. +390712204801email: [email protected]. Pegorin

Previsione delle caratteristiche qualitative di prodotti laminati tramite definizione dei parametri termomeccanici di lavorazione: il sistema Promet 4.0

The objective of this research project was the setting up of a model able to predict the microstructure which, taking into account the rolling schedule and cooling, will be able to provide the mechanical and microstructural characteristics after rolling. The model was developed starting from the theoretical knowledge proposed by many researchers who have dealt with these issues, and the experience gained in the design of rolling systems. In order to allow the maximum working flexibility to the final user, the PROMET system requires to fill in the thermomechanical conditions for rod rolling (preheating temperature, pass reduction, temperature, interpass time, strain rate and cooling profile), and a database of more than 100 steel types was developed, containing CCT curves and the mechanical properties relative to the cooling rate. The tool provides the CCT curves, suitably modified to take into account the microstructure of the rolled, superimposed with the cooling trajectory set up by the operator, as well as mechanical and microstructural data of interest for that particular class of steels. The PROMET system was validated by direct comparison with the properties of rod rolled products under controlled conditions, obtaining an excellent prediction capability

Prediction Models of the final properties of steel rods obtained by thermomechanical rolling process

The objective of this research project was the setting up of a numerical model able to predict the microstructureof rod rolled products which, taking into account the rolling schedule and cooling, is able to provide themechanical and microstructural final characteristics. The model was developed starting from the theoreticalknowledge proposed by many researchers who have dealt with these issues, and the experience gained in thedesign of rolling systems by Siemens-VAI. In order to allow the maximum working flexibility to the final user, theprediction model requires to fill in the thermomechanical conditions for rod rolling (preheating temperature,reduction pass, rolling temperatures, interpass time, strain rate and cooling profile); a database of more than150 steel types was developed, containing CCT curves and the mechanical properties relative to the coolingrates. The tool provides the CCT curves, suitably modified to take into account the microstructure of the rolled,superimposed with the cooling trajectory set up by the operator, as well as mechanical and microstructural dataof interest for that particular class of steel. The Model was validated by direct comparison with the properties ofrod rolled products under controlled conditions, obtaining an excellent prediction capabilit

Anterior nasal versus nasal mid-turbinate sampling for a SARS-CoV-2 antigen-detecting rapid test: does localisation or professional collection matter?

INTRODUCTION: Most SARS-CoV-2 antigen-detecting rapid diagnostic tests require nasopharyngeal sampling, which is frequently perceived as uncomfortable and requires healthcare professionals, thus limiting scale-up. Nasal sampling could enable self-sampling and increase acceptability. The term nasal sampling is often not used uniformly and sampling protocols differ. METHODS: This manufacturer-independent, prospective diagnostic accuracy study, compared professional anterior nasal and nasal mid-turbinate sampling for a WHO-listed SARS-CoV-2 antigen-detecting rapid diagnostic test. The second group of participants collected a nasal mid-turbinate sample themselves and underwent a professional nasopharyngeal swab for comparison. The reference standard was real-time polymerase chain reaction (RT-PCR) using combined oro-/nasopharyngeal sampling. Individuals with high suspicion of SARS-CoV-2 infection were tested. Sensitivity, specificity, and percent agreement were calculated. Self-sampling was observed without intervention. Feasibility was evaluated by observer and participant questionnaires. RESULTS: Among 132 symptomatic adults, both professional anterior nasal and nasal mid-turbinate sampling yielded a sensitivity of 86.1% (31/36 RT-PCR positives detected; 95%CI: 71.3-93.9) and a specificity of 100.0% (95%CI: 95.7-100). The positive percent agreement was 100% (95%CI: 89.0-100). Among 96 additional adults, self nasal mid-turbinate and professional nasopharyngeal sampling yielded an identical sensitivity of 91.2% (31/34; 95%CI 77.0-97.0). Specificity was 98.4% (95%CI: 91.4-99.9) with nasal mid-turbinate and 100.0% (95%CI: 94.2-100) with nasopharyngeal sampling. The positive percent agreement was 96.8% (95%CI: 83.8-99.8). Most participants (85.3%) considered self-sampling as easy to perform. CONCLUSION: Professional anterior nasal and nasal mid-turbinate sampling are of equivalent accuracy for an antigen-detecting rapid diagnostic test in ambulatory symptomatic adults. Participants were able to reliably perform nasal mid-turbinate sampling themselves, following written and illustrated instructions. Nasal self-sampling will facilitate scaling of SARS-CoV-2 antigen testing

Diagnostic accuracy and feasibility of patient self-testing with a SARS-CoV-2 antigen-detecting rapid test.

BACKGROUND: Considering the possibility of nasal self-sampling and the ease of use in performing SARS-CoV-2 antigen-detecting rapid diagnostic tests (Ag-RDTs), self-testing is a feasible option. OBJECTIVE: The goal of this study was a head-to-head comparison of diagnostic accuracy of patient self-testing with professional testing using a SARS-CoV-2 Ag-RDT. STUDY DESIGN: We performed a manufacturer-independent, prospective diagnostic accuracy study of nasal mid-turbinate self-sampling and self-testing with symptomatic adults using a WHO-listed SARS-CoV-2 Ag-RDT. Procedures were observed without intervention. For comparison, Ag-RDTs with nasopharyngeal sampling were professionally performed. Estimates of agreement, sensitivity, and specificity relative to RT-PCR on a combined oro-/nasopharyngeal sample were calculated. Feasibility was evaluated by observer and participant questionnaires. RESULTS: Among 146 symptomatic adults, 40 (27.4%) were RT-PCR-positive for SARS-CoV-2. Sensitivity with self-testing was 82.5% (33/40; 95% CI 68.1-91.3), and 85.0% (34/40; 95% CI 70.9-92.9) with professional testing. At high viral load (≥7.0 log10 SARS-CoV-2 RNA copies/ml), sensitivity was 96.6% (28/29; 95% CI 82.8-99.8) for both self- and professional testing. Deviations in sampling and testing were observed in 25 out of the 40 PCR-positives. Most participants (80.9%) considered the Ag-RDT as easy to perform. CONCLUSION: Laypersons suspected for SARS-CoV-2 infection were able to reliably perform the Ag-RDT and test themselves. Procedural errors might be reduced by refinement of the instructions for use or the product design/procedures. Self-testing allows more wide-spread and frequent testing. Paired with the appropriate information of the public about the benefits and risks, self-testing may have significant impact on the pandemic

Previsione delle caratteristiche qualitative di prodotti laminati tramite definizione dei parametri termomeccanici di lavorazione: il sistema Promet 4.0 = Prediction tool of the qualitative characteristics of rolled products by controlling the thermomechanical parameters: Promet 4.0

The objective of this research project was the setting up of a model able to predict the microstructure which, taking into account the rolling schedule and cooling, will be able to provide the mechanical and microstructural characteristics after rolling. The model was developed starting from the theoretical knowledge proposed by many researchers who have dealt with these issues, and the experience gained in the design of rolling systems. In order to allow the maximum working flexibility to the final user, the PROMET system requires to fill in the thermomechanical conditions for rod rolling (preheating temperature, pass reduction, temperature, interpass time, strain rate and cooling profile), and a database of more than 100 steel types was developed, containing CCT curves and the mechanical properties relative to the cooling rate. The tool provides the CCT curves, suitably modified to take into account the microstructure of the rolled, superimposed with the cooling trajectory set up by the operator, as well as mechanical and microstructural data of interest for that particular class of steels. The PROMET system was validated by direct comparison with the properties of rod rolled products under controlled conditions, obtaining an excellent prediction capability

Prediction of the qualitative characteristics of rod rolled products by controlling thermomechanical parameters: The PROMET 4.0 system

The objective of this research project was the setting up of a numerical model able to predict the microstructure which, taking into account the rolling schedule and cooling, will be able to provide the mechanical and microstructural characteristics after rolling. The model was developed starting from the theoretical knowledge proposed by many researchers who have dealt with these issues, and the experience gained in the design of rolling systems. In order to allow the maximum working flexibility to the final user, the PROMET system requires to fill in the thermomechanical conditions for rod rolling (preheating temperature, pass reduction, rolling temperatures, interpass time, strain rate and cooling profile); a database of more than 150 steel types was developed, containing CCT curves and the mechanical properties relative to the cooling rates. The tool provides the CCT curves, suitably modified to take into account the microstructure of the rolled, superimposed with the cooling trajectory set up by the operator, as well as mechanical and microstructural data of interest for that particular class of steels. The PROMET system was validated by direct comparison with the properties of rod rolled products under controlled conditions, obtaining an excellent prediction capability

Prediction Models of the final properties of steel rods obtained by thermomechanical rolling process

The objective of this research project was the setting up of a numerical model able to predict the microstructure of rod rolled products which, taking into account the rolling schedule and cooling, is able to provide the mechanical and microstructural final characteristics. The model was developed starting from the theoretical knowledge proposed by many researchers who have dealt with these issues, and the experience gained in the design of rolling systems by Siemens-VAI. In order to allow the maximum working flexibility to the final user, the prediction model requires to fill in the thermomechanical conditions for rod rolling (preheating temperature, reduction pass, rolling temperatures, interpass time, strain rate and cooling profile); a database of more than 150 steel types was developed, containing CCT curves and the mechanical properties relative to the cooling rates. The tool provides the CCT curves, suitably modified to take into account the microstructure of the rolled, superimposed with the cooling trajectory set up by the operator, as well as mechanical and microstructural data of interest for that particular class of steel. The Model was validated by direct comparison with the properties of rod rolled products under controlled conditions, obtaining an excellent prediction capability