Titanium Investment Casting Process: Technical Research and Development Introduction

Due to its low density, high specific strength, high-temperature resistance, and corrosion resistance, titanium alloy is widely used in modern industry, especially in the aerospace field. The casting technology of titanium alloys, particularly the titanium investment casting process, is one of the key technologies for producing complex-shaped titanium alloy components. Investment casting technology, also known as precision investment casting or lost wax casting, is a method that uses soluble mold materials to create shell molds and pour metal liquid to form castings. This method can produce castings with low surface roughness and precise dimensions, with high material utilization and almost no limitation on alloy types.

In the technical research of the titanium investment casting process, the selection of mold materials, the preparation of patterns, the dewaxing process, and the selection of facing refractory materials and binders for shell molds are all key aspects. The mold material needs to have a suitable melting point, softening point, good fluidity, and good chemical stability and mechanical properties. Currently, commonly used mold materials mainly include wax-based and rosin-based mold materials. With the growing demand in the aerospace field for large, thin-wall, complex titanium alloy precision castings, research and development of advanced mold materials are continuously progressing.

Titanium Investment Casting Process: Pattern Preparation Technology

Pattern preparation technology includes traditional mold pressing wax and emerging laser rapid prototyping. Mold pressing wax is suitable for mass and large-scale production, but it requires the preparation of production molds, which increases production cycle and research costs. Laser rapid prototyping technology, on the other hand, does not require molds and can directly manufacture complex structural parts, but it is currently unsuitable for mass production.

Titanium Investment Casting Process: Dewaxing Process

The dewaxing process is one of the key steps in the titanium investment casting process. Common dewaxing processes include solvent dewaxing, hot water dewaxing, high-pressure steam dewaxing, electromagnetic wave dewaxing, and burning dewaxing. Each dewaxing process has its characteristics and applicable scenarios; choosing the appropriate dewaxing process is crucial for ensuring the quality of the castings.

Titanium Investment Casting Process: Facing Refractory Materials for Shells

The selection of facing refractory materials for shell molds is critical to improving the quality of titanium alloy castings. Common facing refractory materials include graphite, refractory metal materials, oxide ceramic materials, etc. Among them, oxide ceramic materials such as zirconia and yttria are widely used due to their excellent thermal stability and low thermal conductivity.

Titanium Investment Casting Process: Binders

As an important component of shell molds, binders need to have high thermodynamic stability, strong wetting and binding ability, and good coating forming ability. Common binders include silica sol and zirconium acetate. Silica sol, due to its low cost, wide availability, and excellent performance, is expected to become the mainstream choice of binders in the future.

In summary, the titanium investment casting process is developing towards low cost and high quality. Future research will focus more on the development of new materials, process optimization, and environmental sustainability. With continuous technological advancement, the titanium investment casting process will better meet the demand for high-performance materials in aerospace and other fields.