The ultimate aim of the numerical simulation on temperature field in castings solidification process is for eliminating shrinkage / porosity or limiting them within the user ' s permission 铸件凝固过程温度场数值模拟为最终消除缩孔缩松缺陷或将其限制在用户允许的范围内，以获得质量合格的产品提供了非常有效的手段。
It is because that the forging and heat treatment can greatly change the mechanical properties of steel , reduce the shrinkage cavity and dispersed shrinkage in metal structure , and keep the organizational structure tighter 通过锻造和热处理，可大大改变钢材的力学性能，减少金属结构内的缩孔缩松现象，使其组织结构更紧密。
Abstract : by mean of adjusting the position and shaps of risers , shrinkages and porositi es in balancing axle case are eliminated on the principle of direirional solidification , its density is a lso improved 文摘:根据动态顺序凝固的原则，对斯太尔平衡轴壳铸钢件设计合理的冒口位置和形状；有效地消除了铸件热节部位的缩孔，提高铸件的致密度。
Based on the analysis for the reason causing choke , shrinkage and blow hole defects at two 216 bosses of the main plate of the offset machine , the method to eliminate the casting defects by carrying out qc activities was described 对01胶印机左右大墙板的两个216圆台易出现呛火、缩孔和气孔缺陷的原因进行了分析,介绍了开展qc活动消除01胶印机左右大墙板铸造缺陷的方法。
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 。
Temperature field of hollow ingot solidification is simulated by fem . to different mould , effect of heat transfer coefficient between inner sleeve and cooling medium and thickness of core refractory on final position of solidification , the highest temperature of inner sleeve against cooling medium , and shrinkage cavity and porosity are compared . in addition , change of temperature in typical position of core refractory is also compared 对空心钢锭凝固过程的温度场进行了有限元分析，对不同锭型结构的芯部换热系数、耐火材料厚度对最终凝固位置、内筒壁最高温度及缩孔疏松的影响进行了对比，并讨论了耐火材料典型部位的温度随凝固时间的变化。
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。
Abstract : temperature field of hollow ingot solidification is simulated by fem . to different mould , effect of heat transfer coefficient between inner sleeve and cooling medium and thickness of core refractory on final position of solidification , the highest temperature of inner sleeve against cooling medium , and shrinkage cavity and porosity are compared . in addition , change of temperature in typical position of core refractory is also compared 文摘:对空心钢锭凝固过程的温度场进行了有限元分析，对不同锭型结构的芯部换热系数、耐火材料厚度对最终凝固位置、内筒壁最高温度及缩孔疏松的影响进行了对比，并讨论了耐火材料典型部位的温度随凝固时间的变化。
This control cabinet can control every point temperature in the hot runner , and keep a plastic flow at an optimum condition so that it is possible to avoid such defects as hollow and contraction cavity from lacking in supply , and to save materials and labor and reduce production costs at the same time . compared with ordinary , such hot runner will shorten the time of mould removal , carry out full - automatic ordinary , such hot runner will shorten the time of mould removal , carry out full automatic operation more easily , reduce the distance of mould - opening and the stroke of mould - closing 使用本控制柜能精确控制流道中各点温度，使塑料流动达到最佳状态，这样能克服制件因补料不足而产生凹陷，缩孔等缺陷，同时节省了材料和人力，降低生产成本，与普通流道比脱模周期短，易实现全自动操作，可以缩短开模距与合模行程，缩短成型周期，可以成型较长制品。
Abstract : based on equivalent liquid surface descending method ( elsdm ) and isolated melting zone method , a multi - hot - spot and simultaneous shrinkage - feeding method was established to predict the shrinkage cavities of steel casting during solidification simulation . the shrinkage in each hot spot can be simulated and fed dynamically and simultaneously by itself using this method . then two practical steel castings were analyzed by this method 文摘:本文在等效液面收缩法和孤立域法基础上建立了预测铸钢件缩孔的新方法? ?多热节和即缩即补方法，该法实现了对模拟铸件各热节的内部动态瞬时补缩，并采用该方法对两个实际铸钢件进行了缩孔分析。
