Prediction of gas entrapment defects during zinc alloy high-pressure die casting based on gas-liquid multiphase flow model

Cao, Liu; Liao, Dunming; Sun, Fei; Chen, Tao; Teng, Zihao; Tang, Yulong

doi:10.1007/s00170-017-0926-5

Cited by 25 publications

(9 citation statements)

References 28 publications

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“…Computational fluid mechanics could predict the filling process through calculation and provide a powerful and cost effective tool to control the filling process of die casting, and many new models and methods are presented by many scholars in the HPDC field. Cao et al [6] used the gas-liquid multiphase flow model to predict the air entrainment phenomenon during the die casting filling process of zinc alloy, and the volume of fluid (VOF) was used to track free surface. A water-filling experiment in an S-shaped channel was simulated, and the simulated results were basically consistent with the experimental results.…”

Section: Introductionmentioning

confidence: 99%

“…The simulation result adopted a new model and a new method should be validated experimentally. At the moment, the water analogue experiment is the most common method of experimental fluid mechanics to observe the filling process and to validate the numerical predictions [6,7,8,11,12]. However, although these experiments are designed according to dynamic similarity [13,14], water is not the actual melt.…”

Section: Introductionmentioning

confidence: 99%

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Direct Observation of Filling Process and Porosity Prediction in High Pressure Die Casting

et al. 2019

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Although numerical simulation accuracy makes progress rapidly, it is in an insufficient phase because of complicated phenomena of the filling process and difficulty of experimental verification in high pressure die casting (HPDC), especially in thin-wall complex die-castings. Therefore, in this paper, a flow visualization experiment is conducted, and the porosity at different locations is predicted under three different fast shot velocities. The differences in flow pattern between the actual filling process and the numerical simulation are compared. It shows that the flow visualization experiment can directly observe the actual and real-time filling process and could be an effective experimental verification method for the accuracy of the flow simulation model in HPDC. Moreover, significant differences start to appear in the flow pattern between the actual experiment and the Anycasting solution after the fragment or atomization formation. Finally, the fast shot velocity would determine the position at which the back flow meets the incoming flow. The junction of two streams of fluid would create more porosity than the other location. There is a transition in flow patterns due to drag crisis under high fast shot velocity around two staggered cylinders, which resulted in the porosity relationship also changing from R1 < R3 < R2 (0.88 m/s) to R1 < R2 < R3 (1.59 and 2.34 m/s).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Direct Observation of Filling Process and Porosity Prediction in High Pressure Die Casting

et al. 2019

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“…Therefore, it is extremely important to monitor the mold filling process and predict air trapping in order to obtain high-quality high-pressure die-castings. The improvement of the mold filling process, and thus the casting porosity reduction, is influenced by a change in the mold gating and air venting systems [10][11][12]. When filling high-pressure molds, the most frequently observed phenomenon is turbulent flow, which occurs when the inlet velocity of the melt increases to 0.5 to 15 m/s.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Returnable Material on Internal Homogeneity of the High-Pressure Die-Cast AlSi9Cu3(Fe) Alloy

Matejka

Bolibruchová

Podprocká³

2021

Metals

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Nowadays, high-pressure die-casting technology is an integral part of industrial production. High productivity, reduced machining requirements together with the low weight and advantageous properties of aluminium alloys form an ideal combination for the production of numerous components for various industries. The experimental part of the presented article focuses on the analysis of the change in the ratio of returnable material and commercial-purity alloy in a batch depending on the internal homogeneity of castings (microstructure, porosity and microhardness) from AlSi9Cu3(Fe) alloy. The use of returnable material in the batch is a key factor in achieving the maximum use of aluminium melt, which increases the economic efficiency of production and, last but not least, has a more favorable impact on the environment. Structural analysis showed that the increase in returnable material in the batch was visibly manifested in a change in the morphology of the eutectic Si. A negative change in the morphology of the eutectic Si particles was observed after increasing the returnable material content in the batch to 75%. The evaluation of porosity at control cuts showed the influence of the increase of returnable material in the batch, where the worst results were achieved by the alloy with 90% but also the one with 55% returnable material content in the batch.

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“…Gas-induced porosity is the main limitation and important problem in HPDC [2]. The filling time is extremely short, gas trapped during the high-speed injection causes formation of pores, because of the characteristics of "high-speed filling" of die casting [3,4]. Porosity affects the conventional heat treatment properties of castings, thus degrading the quality of castings [5].…”

Section: Introductionmentioning

confidence: 99%

Effect of Flow State of Pure Aluminum and A380 Alloy on Porosity of High Pressure Die Castings

et al. 2019

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Air entrapment defects prevent the heat treatment from improving the mechanical properties of die castings, which limits the die casting of high-performance components. The flow pattern of the filling process is complicated and experimental analysis is difficult in thin-walled complex die castings. In this study, we constructed a shock absorption tower to observe in real-time the filling process of pure aluminum and A380 aluminum alloy at different fast injection speeds. The degree of breakup of pure aluminum was larger than that of A380 during the filling process, which caused the porosity of pure aluminum to be greater than that of the A380 at each observation position. Re-Oh diagrams explained the difference in porosity between the two metals. The porosity in different regions was closely related to the flow state of aluminum liquid. In addition to porosity measurements, we specifically analyzed the relationship between the porosity of the flowback zone, the final filling zone, and the near-tail zone of cylinder. At the same injection velocity, the porosity at flowback zone was greater than that at the final filling position, the porosity at final filling position was larger than that at the near-tail zone of cylinder, and the final filling position changed as the injection velocity changed.

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Prediction of gas entrapment defects during zinc alloy high-pressure die casting based on gas-liquid multiphase flow model

Cited by 25 publications

References 28 publications

Direct Observation of Filling Process and Porosity Prediction in High Pressure Die Casting

Direct Observation of Filling Process and Porosity Prediction in High Pressure Die Casting

The Influence of Returnable Material on Internal Homogeneity of the High-Pressure Die-Cast AlSi9Cu3(Fe) Alloy

Effect of Flow State of Pure Aluminum and A380 Alloy on Porosity of High Pressure Die Castings

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