Effect of pressure difference on the quality of titanium casting

Area of Science:

• Materials Science
• Metallurgy
• Casting Technology

Background:

• Previous research indicated pressure differences impact titanium casting soundness.
• The relationship between pressure differentials and casting quality requires further investigation.

Purpose of the Study:

• To test the hypothesis that varying argon pressure differences affect titanium casting porosity and mechanical properties.
• To determine the optimal argon pressure for producing high-quality titanium castings.

Main Methods:

• Titanium casting experiments were conducted using a two-compartment machine with varied argon pressure differences (50-450 torr).
• Porosity was quantified using X-ray radiography and image analysis.
• Mechanical properties (tensile strength, elongation, hardness) were measured using universal testing machines and Vickers hardness testing.
• Fracture surfaces were analyzed using Scanning Electron Microscopy (SEM).

Main Results:

• Increased argon pressure differences (300 and 450 torr) led to higher internal porosity and reduced tensile strength and elongation.
• Optimal results were achieved at 150 torr, exhibiting the lowest porosity (approx. 0.8%), highest tensile strength (approx. 540 MPa), elongation (approx. 10%), and bulk hardness (HV50g 209).
• Metal turbulence during casting is proposed as the cause for increased porosity at higher pressures.

Conclusions:

• Argon pressure difference significantly influences the porosity and mechanical integrity of titanium castings.
• An optimal argon pressure difference of approximately 150 torr is recommended for this specific casting geometry to achieve superior mechanical properties and low porosity.
• Careful control of pressure differentials is essential for producing sound titanium castings.