The key to prediction of casting shrinkage / porosity lies in ascertaining the critical value of temperature gradient and niyama criterion . the thesis put forward two methods to ascertain the value , one is which is positive - direction and the other is negative - direction . we verify the realistic arithmetic of temperature gradient method and niyama criterion method by experiment , and we can draw a conclusion that the arithmetic is correct and reasonable in most cases and choice of developing tool is sound 临界梯度值和新山判据临界值的确定是实现缩孔缩松预测的关键,本文提出了确定临界值的正向法和反向法,并以高铬铸铁件缩孔缩松预测和铸造工艺改进为研究对象,应用正向法,确定了温度梯度法的临界值为180 m 。
On the basic of the detailed analysis on main causes and main prediction methods of casting shrinkage / porosity , we put forward two methods to describe the solid phase rate of materials solidification . one is liner - distributing method , and the other is parabola - distributing method . and then , we apply the former to the system 本文在充分分析铸件缩孔缩松产生机理与主要预测方法的基础上,提出了材料凝固固相率的线性分布法和抛物线分布法,并将前者应用于系统中;同时提出了温度梯度法和新山判据法的实现算法,此算法具有一定的灵活性。
温度: temperature梯度: gradient; grad法: law凝固温度梯度法: gradient freeze method密度梯度法: density gradient menthod负温度梯度: negative temperature gradient零温度梯度: zero temperature gradient温度梯度: gradient of temperature; gradient, temperature; moisture gradient; temp grad; temperature grade; temperature gradiant; temperature gradient; temperature lapse rate; temperature slope; temperaturegradient; thermal gradient; thermograde; tone'smal gradient温度梯度炉: gradient furnace温度降;温度梯度: thermal drop垂直温度梯度: vertical temperature grade; vertical temperature gradient辐射温度梯度: radiative temperature gradient过渡温度梯度: transient temperature gradient径向温度梯度: radial symmetry gradient; radial thermal gradient绝热温度梯度: adiabatic lapse rate; adiabatic temperature gradient平面温度梯度: areal temperatuer gradient容许温度梯度: allowable temperature gradient实测温度梯度: measured temperature gradient水平温度梯度: horizontal temperature gradient瞬时温度梯度: transient temperature gradient土壤温度梯度: soil temperature gradient温度梯度测量: temperature gradient measurement温度梯度倒转: inversion of temperature gradient温度梯度电炉: temperature-gradient furnace温度梯度技术: temperature gradient technique