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铸件中的应力是铸件产生热裂、冷裂、挠曲变形等铸造缺陷的根源,常使铸件报废造成严重损失,但多年来铸造应力问题一直未得到很好地解决。 本文对热应力形成过程的一般规律进行了研究,分析了温度分布与产生的热应力之间的关系,通过采用不同蓄热系数的造型材料改变铸件中的温度分布,从而减小铸件中的瞬时应力和残留应力,寻求一条解决实际问题的途径。 实验中所使用的造型材料都是生产中常用的各种型砂,浇注的合金主要是普通碳钢,用容量为50公斤的中频炉熔化,浇注温度(包内)控制在1580～1601℃。采用非稳态线热源法测定型砂的导热系数。采用近年国内新研制的动态应力测定仪测试动态应力,应力框形成的铸造应力通过传感器,将产生的应
Casting stress is casting hot cracking, cold cracking, deflection and other casting defects of the root causes of castings often cause serious damage, but the casting stress over the years has not been a good solution. In this paper, the general law of the thermal stress formation process is studied. The relationship between the temperature distribution and the thermal stress is analyzed. The temperature distribution in the casting is changed by the modeling materials with different heat storage coefficients so as to reduce the instantaneous Stress and residual stress, to find a way to solve practical problems. The molding materials used in the experiments are all kinds of sand commonly used in the production. The cast alloy is mainly ordinary carbon steel, melted by an intermediate frequency furnace with a capacity of 50 kg, and the pouring temperature (within the package) is controlled at 1580-1601 ° C. Determination of Thermal Conductivity of Sand by Unsteady Line Heat Source Method. In recent years, the newly developed domestic dynamic stress tester to test the dynamic stress, the stress frame formed by the casting stress through the sensor, will produce