Porosity easily forms during the manufacturing process of the CW614N alloy, a leaded brass widely used in engineering applications. These porosity issues, often undetected until components are in use, can arise during the casting phase due to gas entrapment or shrinkage cavities, or during extrusion as a consequence of suboptimal parameters, such as temperature and speed. An example of this type of defect was found in a sealing cap made of CW614N brass that failed in an industrial machine, causing a dangerous butane gas leakage at room temperature under atmospheric pressure. Chemical composition analyses were performed to confirm compliance of the failed component with the standard. Metallographic characterizations, including both optical and stereo microscopy and scanning electron microscopy coupled with energy dispersive spectroscopy, were conducted on the failed component to assess its microstructure. Additionally, chemical and microscopy investigations were performed on cast billets and extruded bars produced at varying extrusion speeds (10 mm/s, 25 mm/s, 40 mm/s) and temperatures (620 °C, 670 °C, 720 °C) to understand the causes of the defect and identify extrusion parameters able to minimize it. It was found that the failure can be attributed to the pores’ formation due to the hot tearing phenomenon arising during the extrusion process. Moreover, increasing the extrusion temperature from 620 °C to 720 °C at a speed of 25 mm/s or 40 mm/s significantly reduces the total porosity area in the extruded bars.
Optimization of the manufacturing process to minimize porosity in a CW614N brass sealing cap
Bertoletti L.
;Girelli L.;Montesano L.;Gelfi M.;Pola A.
2025-01-01
Abstract
Porosity easily forms during the manufacturing process of the CW614N alloy, a leaded brass widely used in engineering applications. These porosity issues, often undetected until components are in use, can arise during the casting phase due to gas entrapment or shrinkage cavities, or during extrusion as a consequence of suboptimal parameters, such as temperature and speed. An example of this type of defect was found in a sealing cap made of CW614N brass that failed in an industrial machine, causing a dangerous butane gas leakage at room temperature under atmospheric pressure. Chemical composition analyses were performed to confirm compliance of the failed component with the standard. Metallographic characterizations, including both optical and stereo microscopy and scanning electron microscopy coupled with energy dispersive spectroscopy, were conducted on the failed component to assess its microstructure. Additionally, chemical and microscopy investigations were performed on cast billets and extruded bars produced at varying extrusion speeds (10 mm/s, 25 mm/s, 40 mm/s) and temperatures (620 °C, 670 °C, 720 °C) to understand the causes of the defect and identify extrusion parameters able to minimize it. It was found that the failure can be attributed to the pores’ formation due to the hot tearing phenomenon arising during the extrusion process. Moreover, increasing the extrusion temperature from 620 °C to 720 °C at a speed of 25 mm/s or 40 mm/s significantly reduces the total porosity area in the extruded bars.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
