关于数控机床机座的铸造模式的探讨

文章主要阐述了数控机床利用消失模铸造工艺生产,中压机床机座铸件的生产过程,对冲压机床机座铸件,从浇注位置的选择及浇注工艺的设计,模样组合,涂料涂挂,装箱浇注和过程控制等方面进行了深入探索和实践。     

塑料模具钢大模块生产工艺分析

针对国内塑料模具钢大模块探伤合格率不高的问题,分析了国内外的制造工艺,指出了目前浇注、锻造、热处理过程中可能出现的问题.结果表明: 真空上注法可以改善铸锭心部组织的致密性,通过辅助手段可以提高上注法的表面质量;锻造加热温度的高低应视锭坯的内部质量和锻造设备吨位而定,保证钢锭心部变形有利于钢锭心部缺陷愈合,锻后快冷会增加...     

钢模板台车在斜井浇筑混凝土的研究与应用

采用钢模板台车配合混凝土输送泵在砌碹斜井浇注混凝土,这种施工方法即加快了井筒成井速度,增强了安全性,极大的降低劳动强度,同时,提高了井筒的工程质量,是目前国内较先进的施工方法,为下一步施工提供了经验。     

连铸钢包浇注过程中旋涡的形成机理

连铸钢包浇注末期出现的旋涡卷渣现象会对连铸钢水质量产生重要的影响,为了有效控制生产中的旋涡卷渣现象,对钢包浇注末期旋涡的产生机理开展详细研究.依据相似原理,构建了相似比为1∶6的钢包物理模型,对钢包浇注过程中旋涡产生及卷渣过程进行研究,分析了初始液面高度、出水口尺寸与布置位置、出水口结构等因素对旋涡形成规律的影响.结果表明：旋涡形成过程与初始液面高度无关;钢包出水口尺寸和布置位置对于旋涡形成过程影响显著.随着出水口直径的增大,旋涡临界高度逐渐增加;随着偏心率的增加,旋涡临界高度逐渐降低,最佳偏心率为3/4.提出三片挡块式出水口结构,可以显著降低钢包浇注末期的旋涡临界高度,降低高度达50％左右.     

Scale-Model Experiment and Numerical Simulation of a Steel Teeming Process

During the teeming process of molten steel from a ladle, a bathtub-type vortex may be formed. The vortex entrains undesired slag floating on the surface, lowering the quality. The formation of such vortices was studied using scale models. Since the kinematic viscosity of water is similar to that of molten steel, we used water in our experiments. The particle image velocimetry (PIV) technique was used to measure water flow patterns. Dimensional analysis showed that the Froude number was the governing Π number. A computational fluid dynamics (CFD) model successfully simulated the behavior of the vortex formed in our scale-model experiments.     

Two-phase sink vortex suction mechanism and penetration dynamic characteristics in ladle teeming process

At the late stage of continuous casting (CC) ladle teeming,sink vortex can suck the liquid slag into tundish,and cause negative influences on the cleanliness of molten steel.To address this issue,a two-phase fluid mechanical modeling method for ladle teeming was proposed.Firstly,a dynamic model for vortex suction process was built,and the profiles of vortex flow field were acquired.Then,based on the level set method (LSM),a two-phase 3D interface coupling model for slag entrapment was built.Finally,in combination with high-order essentially non-oscillatory (ENO) and total variation diminishing (TVD) methods,a LSM-based numerical solution method was proposed to obtain the 3D coupling evolution regularities in vortex suction process.Numerical results show that the vortex with higher kinetic energy can form an expanded sandglass-shape region with larger slag fraction and lower rotating velocity;there is a pressure oscillation phenomenon at the vortex penetration state,which is caused by the energy shock of two-phase vortex penetration coupling.     

缩短镇静钢注台静置时间及钢材质量的试验研究

缩短镇静钢注台静置时间试验表明，此工艺相旧工艺缩短注台静置时间８０％，提高铸锭台作业率３０％，不增加设备的投资，提高了武钢－炼钢厂和初轧厂的生产能力，并能提高钢锭，钢材质量。     

浇注钢包环出钢口四孔透气塞吹氩控制下渣工艺北大核心CSCD

针对浇注钢包环出钢口四孔透气塞吹氩控制下渣工艺,建立了某钢厂130 t钢包三维DPM-VOF耦合数学模型以计算浇注钢包下渣过程,并通过冷态实验验证了该模型的有效性。利用该模型研究了不同偏心率对下渣行为的影响,揭示了该工艺控制下渣的行为规律,并分析了吹氩流量对控制下渣的影响。结果表明,随着偏心率的增大,不同浇注高度下的最大切向速度减小,汇流漩涡临界高度降低。环出钢口四孔透气塞吹入氩气后,气泡流股的汇聚有效地减弱了水口上方钢液的周向旋转速度,大幅降低了汇流漩涡下渣临界高度。4个气泡流股的气液两相流会抑制流向水口钢液的径向流动速度,由排流沉坑引起的下渣也得到明显抑制。随着吹氩流量的增加,下渣临界高度呈降低趋势。就本研究而言,控制下渣的最佳吹氩流量为30 L/min。     

倾斜浇注在铸钢件中的应用

通过对倾斜浇注机理的分析及倾斜浇注在铸钢件上的应用实例,说明采用倾斜浇注工艺在某些铸钢件上可以提高工艺出品率10%～20%。