Research on the relationship between sprue conditions and casting defects by means of observation of the titanium flow in a mold cavity

采用示踪元素熔融法，可以明确钛在模腔内的流动行为，所得结果为钛铸件几种缺陷的产生提供了机理。在此期间，我们研究了铸态缺陷与铸态条件对钛流动的影响。离心铸造机的特性由于其层流而变得清晰。尽管每种铸造机、压力铸造机或离心铸造机的铸造机构不同，熔融钛的运动部分是由其在浇道中获得的速度，部分是由内部压力。每个部分都由腔的形状、铸造机和流动条件（层流或湍流）决定。在厚板中，即使在压铸机的情况下，由于流动阻力小，熔融钛也会以其速度运动。用获得超高速的部分钛液制成管状铸件。在网状腔中，钛液的内压对钛液的流动和浇注性能有重要影响。此外，通过离心铸造，可以非常清楚地看到由速度或内压驱动的铸造区域的各个部分。综上所述，当我们研究完整的钛铸件时，我们必须始终关注驱动力，钛的熔融速度或内部压力。

By means of the tracer element molten method, the titanium flow behavior in the mold cavity can be clarified and the obtained results provide the mechanism of the several defects of titanium castings.In this period, we investigate the relationship between the casting defects and the titanium flow affected by the sprue conditions. The characterization of a centrifugal casting machine has become clear because of its laminar flow. In spite of the casting mechanism of each casting machine, pressure casting machine or centrifugal casting machine, the molten titanium was moved partly by its velocity obtained in sprue and partly by the internal pressure. Each part has been governed by the shape of the cavity, casting machine, and flow condition (laminar or turbulent). In thick plate, even in the case of the pressure casting machine, molten titanium moves by its velocity because of small flow resistance. The pipe like casting was made by the part of molten titanium which obtained the excess velocity. In the mesh type cavity, the internal pressure of the molten titanium was very important for smooth flow and castability. Furthermore, each part of the casting areas which were moved by the driving force of either the velocity or the internal pressure was very clear by the use of the centrifugal casting. In conclusion, when we investigate the complete titanium casting, we must always concern the driving force, the velocity of molten titanium or the internal pressure.