Hardware Pivot Titanium Alloy Lost-wax Casting
Hardware shafts play a crucial role in connecting and rotating components in many pieces of equipment. Using titanium alloy provides advantages such as high strength, low density, and excellent corrosion resistance. Lost-wafer casting is a precision casting method, particularly suitable for manufacturing hardware shafts with complex shapes and high precision requirements.
Overview of Lost-Wafer Casting Process for Titanium Alloy Hardware Shafts
Hardware shafts play a crucial role in connecting and rotating components in many pieces of equipment. Using titanium alloy provides advantages such as high strength, low density, and excellent corrosion resistance. Lost-wafer casting is a precision casting method, particularly suitable for manufacturing hardware shafts with complex shapes and high precision requirements.
Titanium Alloy Material Characteristics
High Strength
Titanium alloys possess high strength, capable of withstanding significant external forces and torques, ensuring that hardware shafts are not easily deformed or damaged during use, meeting the strength requirements of various equipment.
Low Density
Compared to traditional metals such as steel, titanium alloys have a lower density, making hardware shafts made from titanium alloys lighter. In equipment with strict weight requirements, such as aerospace and electronic products, this effectively reduces overall weight, improving equipment performance and efficiency.
Corrosion Resistance
Titanium alloys form a dense oxide film on their surface, exhibiting excellent corrosion resistance, allowing them to be used in harsh environments, such as humid environments or those with chemical corrosive substances, extending the service life of the hardware shafts.
Lost-wax casting process principle
Losed-wax casting, also known as investment casting, involves first creating a wax model with the same shape as the metal shaft. Then, multiple layers of refractory material are coated onto the wax model to form a single shell. Next, the shell is heated, causing the wax model to melt and flow out, creating a cavity within the shell that matches the shape of the metal shaft. Finally, molten titanium alloy is poured into the cavity, and after cooling and solidification, the shell is removed to obtain the desired metal shaft.
Specific process of titanium alloy lost-wax casting for metal shafts
1. Mold design and manufacturing: Based on the design drawings of the metal shaft, a 3D model is created using CAD software. Then, a mold is manufactured based on the model to make the wax model. The precision and quality of the mold directly affect the quality of the wax model; therefore, it is necessary to ensure the dimensional accuracy and surface finish of the mold.
2. Wax material selection and treatment: A suitable wax material is selected, generally requiring good fluidity and low shrinkage. The wax material is heated and melted, and impurities and air bubbles are removed to ensure the quality of the wax model. 3. Wax Model Forming: Molten wax is poured into the mold, and under specific pressure and temperature conditions, the wax fills the mold cavity. After the wax cools and solidifies, the mold is opened, and the wax model is removed. The wax model is then trimmed and inspected, removing excess wax and flash to ensure that the dimensional accuracy and surface quality meet requirements.
1. Refractory Material Coating: The wax model is immersed in a coating composed of refractory materials (such as silica sol, zircon sand, etc.) and a binder, ensuring a uniform coating on the surface. The coated wax model is then placed in a sand box, and a layer of refractory sand is sprinkled on top, allowing the sand particles to adhere to the coating surface, forming the first layer of the shell.
2. Multi-Layer Coating: The above process of coating and sanding is repeated to form multiple layers of the shell on the wax model surface. Generally, 5-7 layers are required, with each layer having a different particle size of coating and sand to ensure sufficient strength and permeability of the shell. 3. Shell Drying and Hardening: After each layer of shell coating is applied, drying and hardening treatment is required to solidify the binder in the shell and improve its strength. The drying and hardening time and conditions depend on the type of coating and binder, and generally need to be carried out under specific temperature and humidity conditions.
1. Dewaxing: The prepared shell is placed in a dewaxing furnace and heated to a certain temperature to melt the wax and allow it to flow out of the shell. There are various dewaxing methods, such as steam dewaxing and hot water dewaxing; the appropriate method is selected based on the actual situation.
2. Firing: The dewaxed shell needs to be fired to remove residual wax and moisture, improving its strength and high-temperature resistance. The firing temperature and time depend on the material and thickness of the shell, and generally need to be carried out in a high-temperature furnace, with firing temperatures reaching 800-1000℃.
1. Titanium Alloy Melting: Select suitable titanium alloy raw materials and prepare the mixture according to the required chemical composition.
2. Mixing: The raw materials are placed in a vacuum induction melting furnace and heated and melted under vacuum to ensure thorough and uniform mixing of all elements. During the melting process, parameters such as melting temperature, time, and vacuum level must be strictly controlled to guarantee the quality of the titanium alloy.
3. Pouring: The molten titanium alloy is quickly poured into a preheated mold cavity, ensuring the cavity is completely filled. During pouring, attention must be paid to parameters such as pouring speed, pouring temperature, and pouring pressure to avoid casting defects such as porosity and inclusions.
1. Mold cleaning: After the molten titanium alloy cools and solidifies, the mold cavity is removed. Methods such as mechanical vibration and sandblasting can be used to break and remove the mold cavity, exposing the blank of the metal shaft.
2. Heat treatment: The metal shaft blank undergoes heat treatment to improve its microstructure and properties. Common heat treatment processes include annealing, quenching, and tempering. The appropriate heat treatment process is selected based on the type of titanium alloy and the application requirements.
3. Machining and Surface Treatment: The heat-treated metal shafts undergo machining processes such as turning, milling, and grinding to achieve the required dimensional accuracy and surface roughness. Then, surface treatments such as electroplating and spraying are applied to improve their corrosion resistance and aesthetics.
Quality Control of Titanium Alloy Lost-Wafer Casting for Metal Shafts
Raw Material Quality Control
Strict quality inspections are conducted on raw materials such as titanium alloy, wax, and refractory materials to ensure their chemical composition and physical properties meet requirements. Suppliers of raw materials are evaluated and managed, and reliable suppliers are selected.
Process Quality Control
A rigorous quality control system is established for each production stage, including wax model making, shell making, melting, and casting. Key process parameters are monitored and controlled in real time. Inspections and spot checks are strengthened throughout the production process to promptly identify and resolve quality issues.
Finished Product Inspection
A comprehensive inspection is conducted on the finished metal shafts, including checks on dimensional accuracy, surface quality, chemical composition, and mechanical properties. Advanced testing equipment and methods, such as coordinate measuring machines, spectrometers, and hardness testers, are employed to ensure that the quality of the metal hinges meets design requirements.
Application Prospects of Titanium Alloy Lost-Wafer Casting for Metal Hinges
Aerospace Industry
Aerospace equipment has extremely high requirements for the weight, strength, and corrosion resistance of its components. Metal hinges manufactured using titanium alloy lost-wafer casting can meet these requirements. For example, hinges in aircraft engines and landing gear can be reduced in weight and improved in performance and reliability using titanium alloy lost-wafer casting.
Electronic Equipment Industry
As electronic products develop towards miniaturization, lightweighting, and high performance, the requirements for the precision and quality of metal hinges are also increasing. Titanium alloy lost-wafer casting can manufacture complex-shaped, high-precision metal hinges, suitable for hinge components in electronic devices such as mobile phones, tablets, and laptops.
Medical Device Industry
Medical devices have high requirements for the biocompatibility, corrosion resistance, and precision of their components. Titanium alloys have good biocompatibility and corrosion resistance, and the lost-wafer casting process can manufacture metal hinges that meet the requirements of medical devices. For example, rotating components in surgical instruments and rehabilitation equipment.
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