65 62015 224 228 ** Journal of The Japan Institute of Light Metals, Vol. 65, No. 6 (2015), 224 228 2015 The Japan Institute of Light Metals Investigation of heat flow behavior on die-casting core pin with direct measurement of die surface temperature and heat flux Suguru TAKEDA* and Shin ORII* Thermal behavior between casting and core pin/die in high pressure aluminum die-casting was investigated with direct temperature measurement by calculating surface temperature and heat flux. It is proved that there are three heat transfer stages from casting to core pin and that furthermore three types of heat flux curves are there depending on casting volume and cooling conditions. Under sufficient cooling conditions with higher heat flux, the surface temperature of core-pin would not exceed solidus temperature and chilled structure appears on the surface of the casting. On the other hand, insufficient cooling conditions, no chilled structure could be observed but spheroidization of eutectic silicon particles with soldering defects on the surface could be expected. (Received October 28, 2014 Accepted February 28, 2015) Keywords: heat transfer, heat flux, die surface temperature, aluminum high pressure die-casting, core pin 1. 1 2 3 4 5 7 CAE 8 12 Fig. 1 2 Fig. 1 Typical die-casting shapes: plate and cylinder. * 441 3114 1 2 Technical Center, Ahresty Corporation (1 2 Nakahara, Mitsuya-cho, Toyohashi-shi, Aichi 441 3114)E-mail: suguru_takeda@ahresty.co.jp
J. JILM 6520156 225 2. 2. 1 330 ϕ10mm ϕ30mm ϕ50mm 2 Fig. 2 Fig. 3 ϕ7mm 7 Table 1 Table 2 ADC12Al 11%Si Cu Mg 2. 2 2. 2. 1 2 Fig. 4a 2 X 1, X 2 θ 1, θ 2 13 Fig. 4b Table 1 Casting conditions. Parameters Value Metal pressure (MPa) 57.8 Shot weight (kg) 0.8 Tip diameter ϕ80 Filling percentage at second phase (%) 70 Curing time (s) 7 Plunger speed (m/s) 2.0 Gate velocity (m/s) 30.0 Holding temperature (K) 96315 Die temperature (K) 39315 Alloy ADC12(JIS) Table 2 Experimental conditions. Experimental number Casting outer diameter (mm) Core pin diameter outer (inner) (mm) Water line pressure (MPa) Fig. 2 Schematic illustration of casting. 1. 30 0.1 2. 30 1.9 10 (7) 3. 50 0.1 4. 50 1.9 Fig. 3 Schematic illustration of sensing point in detail. Fig. 4 Detecting principal of surface temperature and heat flux.
226 6520156 Fig. 3 2 0.5 mm K 5 1 ms 10 2. 2. 2 θϕ Fig. 3 1a1b 2 2a 2b SKD 61 30 W/m K Fig. 5 Measured surface temperatures and heat fluxes of die and core pin at cooling line pressure 0.1 MPa. 中 子 ピン 表 面 温 度 : Θ= θ ( ( ln( r/ r )/ln( r / r )) ( θ θ ) (1a) 2 2 1 2 2 1 中 子 ピン 熱 流 束 :φ =2 πλ ( θ θ )/ l n( r / r ) (1b) 1 2 1 2 金 型 の 表 面 温 度 : Θ= θ (( θ θ ) x )/( x x ) (2a) 2 2 1 2 2 1 金 型 の 熱 流 束 :φ = λ ( θ θ )/( x x (2b) 2 1 2 1 ) Θ θ 2 θ 1 x 2, r 2 x 1, r 1 λ ϕ 3. Fig. 5Fig. 8 790 K 40006000 kw/m 2 3. 1 Fig. 5 10 Fig. 6 Measured surface temperatures and heat fluxes of die and core pin at cooling line pressure 1.9 MPa. 790 K 3 3. 2 Fig. 6 3.1 3. 3 Fig. 7
J. JILM 6520156 227 3.2 790 K 4 3. 4 Fig. 8 3.3 3. 5 ϕ50 10 0.1 MPa ϕ3010 1.9 MPa Fig. 9 ϕ50 Fig. 9 Si 1 mm Si Fig. 9 4. 4. 1 Fig. 10 3 3 I II I III 3 A B C Fig. 7 Measured surface temperatures and heat fluxes of die and core pin at cooling line pressure 0.1 MPa. Fig. 9 Optical microstructures in typical conditions. Fig. 8 Measured surface temperatures and heat fluxes of die and core pin at cooling line pressure 1.9 MPa. Fig. 10 Heat flux curves in various conditions.
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