Effects of Water Quench on Grain Refining and Mechanical Properties of Aluminum Die-Casting Rims
by Shueiwan H. Juang1*, Chien-Cheng Chen2
摘 要
壓鑄製程可分為熔解金屬、充模成形及鑄件取出等三個階段，當鑄件取出後，在剪緣
作業前，有時會將鑄件浸入水中冷卻，以利剪緣作業的穩定性。本研究旨在探討鋁合金鑄
件在浸水過程對鑄件品質的影響，比較鑄件經浸水冷卻與自然冷卻之機械性質和微觀組織
差異，並利用商用軟體分析鑄件計算浸水冷卻之最佳化時間。本研究之載具係使用ADC10
鋁合金製成之輪圈，在鑄件取出後，分別以浸水冷卻和自然空冷方式予以降溫至剪緣溫度，
接著從輪圈試樣截取檢驗試片，進行拉伸試驗及金相試驗，比較兩種冷卻方式下鑄件的機
械性質及微觀組織的差異。研究結果顯示，使用浸水冷卻的輪圈硬度較自然空冷輪圈高
15%，其抗拉強度和延伸率也較自然空冷輪圈分別高4%和7%。二次晶臂間距（SDAS）量
測結果顯示，浸水冷卻輪圈的SDAS值較自然空冷輪圈低17%。另外，熱傳分析結果顯示，
鑄件浸水冷卻的最佳化時間為6 sec。本研究結果顯示鋁輪圈鑄件經浸水冷卻可有效提升鑄
件的機械性質和達到晶粒細化效果。
關鍵詞：壓鑄件、浸水冷卻、機械性質、晶粒細化、最佳浸水時間
ABSTRACT
The die-casting process is divided into three stages, namely melting, melt filling, and
ejecting. After ejection, the casting is sometimes immersed in water for fast cooling before the
trimming operation to improve the stability of trimming process. This paper aims to study the
effect castings on the quality being applied water soaking and to compare the mechanical
properties and microstructures differences between water immersion cooled and natural air
cooled. In addition, a commercial software is used to analyze the optimal time of castings by
water immersion cooled. The die-castings used in this study are rims made of ADC10 aluminum
alloy. After ejection the castings are cooled to the trimming temperature by either waterimmersion cooled or natural air cooled. Specimens for microstructure examination and tensile
tests are then cut and machined from the rims. The results showed that the hardness of the rim
using water immersion cooled is 15% higher than that of the natural air-cooled, and its tensile
strength and elongation are 4% and 7% higher than that of the natural air-cooled. Results of the
Secondary Dendrite Arm Spacing (SDAS) measurements revealed that the SDAS value of the
water-cooled rim is 17% smaller than that of the natural air-cooled rim. In addition, the results of
heat transfer analysis showed that the optimal immersion time for the rim casting is 6 sec. The
results of this study showed that Al alloy rim castings by water immersion cooled can effectively
improve the mechanical properties of the castings and the effect of grain refinement.
Keywords: Die casting, water immersion cooled, mechanical properties, grain refinement,
optimal water immersion time
