Lost-wax Casting Of Titanium Alloy For Washing Machines

First, a high-precision mold is made according to the design drawings of the required titanium alloy parts for the washing machine. Then, wax is heated and melted, poured into the mold, and removed after cooling. The dimensional accuracy and surface quality of the wax model directly affect the quality of the final titanium alloy parts. Therefore, process parameters must be strictly controlled during manufacturing to ensure that the dimensional deviation of the wax model is within a minimal range and that the surface is smooth and flawless.

The wax model is immersed in a coating composed of refractory material and binder, uniformly covering the surface with a layer of coating. Then, a layer of sand is sprinkled on top. This process is repeated several times to form a shell of a certain thickness. The strength and permeability of the shell are crucial to the casting quality. Insufficient strength may cause the mold shell to crack during casting, while poor permeability will affect gas escape and cause defects such as porosity.

The wax mold with the mold shell is placed in a steam dewaxing kettle or hot water to melt the wax and allow it to flow out of the mold shell, forming a cavity. The dewaxing process must ensure complete removal of wax; otherwise, residual wax will cause problems such as porosity and inclusions during casting.

The dewaxed mold shell is placed in a firing furnace for high-temperature firing to remove moisture, organic matter, and other impurities, while improving the strength and refractoriness of the mold shell. The firing temperature and time need to be precisely controlled according to the material and thickness of the mold shell to ensure optimal performance.

The titanium alloy raw material is placed in a vacuum induction furnace for melting. During the melting process, the temperature and time are strictly controlled to ensure uniform alloy composition. When the titanium alloy reaches the appropriate casting temperature, it is poured into the cavity of the mold shell under vacuum or a protective atmosphere. The pouring speed and volume also need precise control to avoid defects such as incomplete pouring and cold shuts.

After pouring, allow the titanium alloy to cool naturally in the mold. The cooling rate affects the microstructure and properties of the titanium alloy, so it needs to be appropriately controlled according to the requirements of the part. After cooling, remove the mold using mechanical or chemical methods, and clean and grind the part to remove burrs, oxide scale, and other impurities from the surface.

The cleaned titanium alloy parts undergo heat treatment to improve their microstructure and properties, increasing strength, hardness, and toughness. Surface treatments, such as electroplating and spraying, may also be necessary to improve the corrosion resistance and aesthetics of the parts. Finally, the parts undergo quality inspection, including checks on dimensional accuracy, surface quality, and internal defects, to ensure that the parts meet the requirements for use in washing machines.