Comparative Study on Casting Properties of One-chamber Pressure Type and Two-chamber Pressure Type by Titanium Flow Observation

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To clear the difference in casting properties between one-chamber pressure machine and two-chamber pressure machine, titanium flow in various cavities was investigated by the tracer element molten method which is one of flow visualization techniques developed in this research. Casting defects were also checked by X-ray transparent photographs.The summary of the obtained results is shown below.1.The inflow of the one chamber type was presumed to be faster than the two chamber type, which is due to the higher pressure and its quick operation.2.In thick cavity, turbulent flow sometimes occured and in such a case many large internal defects generated because solidification shell finished later than that of laminar flow. (onechamber type)3.In thin cavity, external defect occured because the filling times was longer than that of pressure elevation in cavity due to diffusion of argon. (one chamber type)4.As a result in the case of one chamber type, investments with high permeability cause many internal defects in thick plate castings and external defects on thin plate castings and mesh castings. Those defects closely related to the flow in the cavity. Low permeable investment caused few casting defects in spite of cavity type.