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目前,铝活塞的铸造通常都是采用硬模浇注。由于浇口和冒口在整个投炉料中所占的比例很大,而且切割下来后都返回熔炉进行重复浇注。所以在计算烧损率时,必须将投炉料的一次性烧损率和重复烧损率一起来考虑。 铝合金浇注时投炉料的一次性烧损率可以通过实际测量求出。从数理统计学中我们知道,测量次数越多,其测量值的算术平均值就越接近测量值χ_i随机变量的期望。因此,投炉料的第一次烧损率可以用下式计算。
At present, casting aluminum pistons are usually cast using a hard mold. As the gate and riser in the cast material in a large proportion, and after cutting back to the furnace for repeated pouring. Therefore, in calculating the burning rate, you must cast one-time burning rate of burned material and repeat burning rate to consider together. Cast aluminum alloy casting one-time burning rate can be obtained by the actual measurement. From mathematical statistics we know that the more the number of measurements, the closer the arithmetic mean of the measurements to the expected value of the random variable χ_i. Therefore, the first burning rate of charge material can be calculated using the following formula.