The main goal of this work is to investigate the effects of scrap mix and fluxes used for the melt charge on the microstructure and solidification defects of CuZn40Pb2 (CW617N) brass billets produced by continuous casting. Optical microscopy, scanning electron microscopy, energy dispersion X-ray spectroscopy, and X-ray diffraction analyses were conducted to characterize the microstructure of the produced billets, detect macroscopic cracks and other solidification defects, as well as determine the characteristics of the slags formed in the melting furnace depending on the process conditions. Experimental results showed that the characteristics of CuZn40Pb2 billets did not vary significantly with the different charging conditions, indicating that the production process is robust and well consolidated. The microstructure of the cast billets mostly consisted of (α) and beta (β) phases with lead particles distributed at the grain boundaries or within the grains of the constituent phases. Only seldom, severe solidification defects and large inclusions were found in the analyzed billets and their occurrence could not be associated to specific casting conditions. The large number of analyzed specimens displayed a low amount of surface and bulk defects and low amount of non-metallic inclusions.
L’obiettivo principale di questo lavoro è studiare gli effetti della composizione della materia prima e dei flussi utilizzati per la carica di fusione sulla microstruttura e sui difetti di solidificazione di billette di ottone CuZn40Pb2 (CW617N) prodotte tramite colata continua. Per caratterizzare la microstruttura delle billette prodotte, rilevare cricche macroscopiche e altri difetti di solidificazione e determinare le caratteristiche delle scorie formate nel forno fusorio in base alle condizioni di processo, sono state condotte analisi di microscopia ottica, microscopia elettronica a scansione, spettroscopia a dispersione di energia e diffrazione di raggi X. I risultati sperimentali hanno mostrato che le caratteristiche delle billette di CuZn40Pb2 non variavano significativamente nelle diverse condizioni di carica, indicando che il processo di produzione è robusto e ben consolidato. La microstruttura delle billette colate era costituita prevalentemente da fasi alfa (α) e beta (β) con particelle di piombo distribuite a bordo grano o all'interno dei grani delle fasi costituenti. Difetti di solidificazione severi e grandi inclusioni sono stati raramente osservati nelle billette analizzate e non è stato possibile associare la loro comparsa a specifiche condizioni di colata. A monte di un ampio numero di provini analizzati si può notare una quasi assenza di difetti sia superficiali che volumetrici, oltre a una scarsa presenza di inclusioni non metalliche.
Investigation on the continuous casting process of CuZn40Pb2 (CW617N) brass
Bizzari, Luca
2023/2024
Abstract
The main goal of this work is to investigate the effects of scrap mix and fluxes used for the melt charge on the microstructure and solidification defects of CuZn40Pb2 (CW617N) brass billets produced by continuous casting. Optical microscopy, scanning electron microscopy, energy dispersion X-ray spectroscopy, and X-ray diffraction analyses were conducted to characterize the microstructure of the produced billets, detect macroscopic cracks and other solidification defects, as well as determine the characteristics of the slags formed in the melting furnace depending on the process conditions. Experimental results showed that the characteristics of CuZn40Pb2 billets did not vary significantly with the different charging conditions, indicating that the production process is robust and well consolidated. The microstructure of the cast billets mostly consisted of (α) and beta (β) phases with lead particles distributed at the grain boundaries or within the grains of the constituent phases. Only seldom, severe solidification defects and large inclusions were found in the analyzed billets and their occurrence could not be associated to specific casting conditions. The large number of analyzed specimens displayed a low amount of surface and bulk defects and low amount of non-metallic inclusions.File | Dimensione | Formato | |
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2024_12_Bizzari.pdf
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Descrizione: Testo tesi ottone CW617N
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https://hdl.handle.net/10589/229795