Structural characterization and detecting processes of defects in leaded brass alloy used for gas valves production

Fadhil, Abdulsalam A.; Ghattas, Magdy Samuel; Iskander, B. A.; Ajeel, Sami A.; Enab, Tawakol A.

doi:10.1016/j.aej.2017.04.017

Cited by 14 publications

(4 citation statements)

References 13 publications

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“…Samples were prepared using a standard metallographic preparation procedure, including grinding, mechanical polishing, and final polishing by colloidal silica. For OM observations, the samples were chemically etched in a solution that consisted of 8.3 g of FeCl 3 , 10 mL of HCl, and 90 mL of H 2 O [18]. Analysis of lead particle size and area fraction and the β phase area fraction and grain size was conducted using ImageJ, an automated image analysis system [25].…”

Section: Methodsmentioning

confidence: 99%

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Microstructure and Texture Development in Thermomechanically Processed Leaded Brass

Al‐Fadhalah

Rafeeq

N.R.Thomas

2021

Metals

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Leaded brass alloys with high zinc content are classified as dual-phase (α-β′) brass alloys. For these alloys, α-β′ phase transformation induced by thermomechanical processing (TMP) is expected to play a significant role not only in the formation of α and β′ phases and uniformity of lead particles but also in the development of Σ3 boundaries and their variants in the α phase. To assess such impact, the current study has employed two TMP schemes, with each scheme consisting of four cycles of compression and annealing. Samples of the first scheme (TMP-1) were annealed at 670 °C to promote phase transformation from α to β′, as compared to the second scheme (TMP-2) samples annealed at 525 °C. Microstructure examination indicated that TMP-1 scheme fostered a remarkable growth in the area fraction of β′ phase, accompanied by grain coarsening of α and β′ phases. This resulted in the isolation of α grains and less interaction of Σ3 boundaries at trip junctions, and therefore, a reduction in the fraction of Σ3 boundaries occurred in the α phase. On the other hand, the TMP-2 scheme successfully enhanced cluster formation of α grains, enabling further generation of Σ3 boundaries via strain-induced boundary migration mechanism and ultimately leading to breakup of the random boundary network. In addition, the two schemes resulted in limited coarsening of lead particles. Most lead particles were located at the α-βʹ interfaces, which suppressed grain boundary migration via the particle-dragging effect. For both TMP schemes, the initial texture of tension fibers was largely preserved after four cycles for both α and βʹ phases. Nevertheless, the TMP-2 scheme produced texture randomization of the α phase due to increasing the fraction of Σ3 boundaries.

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Section: Methodsmentioning

confidence: 99%

“…Several works have examined the microstructure development in leaded brass to evaluate its mechanical properties and machining performance [15,[17][18][19][20]. For example, Pantazopoulos and Vazdirvanidis [15] reported that decreasing lead particle size and increasing lead particle density improves machinability.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Texture Development in Thermomechanically Processed Leaded Brass

Al‐Fadhalah

Rafeeq

N.R.Thomas

2021

Metals

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Section: Introductionmentioning

confidence: 99%

“…[2] Last but not least, the recent study by Fadhil et al documented that using 30% pure original material, together with optimized processing parameters of casting, extrusion, and subsequent hot and cold forming, can enhance the properties of the final brass valve, as well as reduce/eliminate the risk of failure. [20] According to the published studies, one of the main factors determining the final properties of brass products is structure morphology, grain size in particular (lower grain size affects positively the final properties). This hypothesis was also confirmed by the recent study by Naser Radhi et al [21] reporting significant improvement in mechanical properties of brass after processing via equal channel angular pressing (ECAP).…”

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confidence: 99%

Effects of Temperature (In)homogeneity during Hot Stamping on Deformation Behavior, Structure, and Properties of Brass Valves

Kunčická

Kocich

2021

Adv Eng Mater

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Herein, assessing the effects of initial temperature (in)homogeneity on a hot‐stamped CuZn40Pb2 medical gas valve (fitting) via numerically and experimentally defining mutual relations of selected deformation parameters and optimizing temperature distribution within the original semi‐product heated via induction are focused. For these purposes, three preheating regimes are simulated, and deformation behaviors are evaluated. The predicted results are validated by experimental stamping and subsequent evaluation of the structure and properties of stamped fittings. The results show that preheating the semi‐product with a certain temperature gradient occurring between the axial and (sub)surface regions is favorable, as homogeneous initial temperature distribution results in rapid surface cooling by the effect of heat transfer from semi‐product to die, which imparts inhomogeneous stress distribution, local changes in structural phases, and possible occurrence of oxides. Too low (sub)surface temperature of the semi‐product can result in a significant (local) increase in flow stress, which consequently results in the danger of occurrence of forming defects. The brass fitting stamped with the optimized preheating procedure features an average grain size of 5.8 μm, uniform grains’ orientations with maximum texture intensity of two times random, and ultimate tensile strength of almost 400 MPa, while maintaining elongation to failure of more than 35%.

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Incorporating outsourcing, stochastic failure, and scrap into batch fabrication planning

Chiu

Jhan

Chiu

et al. 2020

Alexandria Engineering Journal

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Structural characterization and detecting processes of defects in leaded brass alloy used for gas valves production

Cited by 14 publications

References 13 publications

Microstructure and Texture Development in Thermomechanically Processed Leaded Brass

Microstructure and Texture Development in Thermomechanically Processed Leaded Brass

Effects of Temperature (In)homogeneity during Hot Stamping on Deformation Behavior, Structure, and Properties of Brass Valves

Incorporating outsourcing, stochastic failure, and scrap into batch fabrication planning

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