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采用冷却斜管工艺以及在金属铸型中预放热电偶的方法,考察了A357合金在不同浇注温度下,经不同长度的斜管处理后,合金液的最高温度以及凝固组织的变化。结果表明:对A357合金进行冷却剪切处理,可有效的细化、球化凝固组织;浇注温度,斜管长度都会影响A357合金最终的凝固组织,随着浇注温度的降低以及斜管长度的增加,A357合金凝固组织中粗大的枝晶向玫瑰晶以及细小的球状晶转变;浇注温度在660℃时,经300、450、600 mm斜管处理后,进入铸型的合金液处于半固态区间,而在690、720℃浇注时,经斜管处理后的合金液仍为液态。
The cooling inclined tube technology and the method of preheating the thermocouple in the metal mold were used to investigate the maximum temperature of the alloy liquid and the change of the solidified structure of the A357 alloy after being treated with different lengths of inclined tubes under different pouring temperatures. The results show that the cooling and shearing treatment of A357 alloy can effectively refine and spheroidize the solidified structure. The pouring temperature and the length of inclined tube all affect the final solidified microstructure of A357 alloy. With the decrease of pouring temperature and the increase of inclined tube length , The coarse dendrites in the solidified microstructure of A357 alloy transformed into rose crystals and fine spherical crystals. When the pouring temperature was 660 ℃, the alloy liquid entering the mold was in the semi-solid state after being processed by 300,450,600 mm inclined tubes, When pouring at 690 and 720 ℃, the alloy liquid treated by the inclined tube is still liquid.