Customized machining process of alumina ceramic valve

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Alumina ceramic valves are widely used in various industrial valves due to their excellent wear resistance, corrosion resistance and high hardness. Custom machining of alumina ceramic valves requires several precise steps:

I, preliminary preparation

1. Demand confirmation
   Before processing, it is necessary to communicate fully with the customer to clarify the specific requirements for the size, shape, surface roughness, and performance parameters of the alumina ceramic valve.
2. Selection of raw materials
   Select the appropriate alumina raw material according to the product requirements. Common alumina ceramics are divided into 99 porcelain, 95 porcelain, 92 porcelain, etc. according to the content of Al2O. For valve plates, high-purity (such as 99% or 95%) alumina powder is usually selected to ensure its wear resistance and corrosion resistance.
3. Equipment preparation
   Prepare numerical control machine tools, grinding machines, polishing machines, sintering furnaces and other processing equipment, and carry out debugging and inspection.

II, powder preparation
STEP 1 Mixing of raw materials
Mix alumina powder with other additives (such as binders, lubricants, etc.) in a certain proportion. For example, when dry pressing is used, 1% to 2% lubricant (such as stearic acid) needs to be added.

2. Ball milling treatment
   The mixed raw materials are added to the ball mill for ball milling, so that the particle size reaches less than 1 μm to ensure the uniformity and fineness of the powder. For complex shaped valve plates, separate ball milling of raw materials with different particle sizes may be required.
3. Spray granulation
   Spray granulation was used to treat the powder to make it appear spherical to improve the fluidity and molding properties of the powder.

III. Molding process

1. Dry pressing
   Dry press molding is a common method for making alumina ceramic valves, which is suitable for products with complex shapes and high dimensional accuracy requirements. Put the powder into a mold and apply pressure (usually 100-200 MPa) to press.
2. Injection Molding
   For high-volume production of complex shaped valves, injection molding is ideal. By mixing the powder with a binder and injecting it into the mold, the molding is released after molding.
3. Grouting
   For large size or complex shape of the valve, can use grouting molding. The powder mixed with water into a slurry, injection into the gypsum mold, after solidification demoulding.

IV. Sintering and cooling

1. Degreasing treatment
   For injection molded green bodies, degreasing treatment is required to remove the binder.
2. Sintering
   The formed body is placed in a sintering furnace for sintering. The sintering temperature is usually between 1200 ° C and 1600 ° C, depending on the purity of the alumina and product requirements. For example, the sintering temperature of 99% alumina ceramics can be as high as 1600 ° C.
3. Cooling
   After sintering is completed, it is necessary to slowly cool to room temperature to avoid cracking or deformation of the product due to rapid temperature changes.

V. Finishing

1. Grinding and polishing
   The surface of the sintered valve plate may have minor irregularities that require grinding and polishing to achieve the desired surface roughness. For example, MARUWA’s ceramic valve plates use high-precision surface grinding technology to ensure their sliding performance.
2. Dimensional inspection
   Use high-precision measuring equipment to check the size of the machined valve to ensure that it meets the design requirements.

VI. Quality inspection and packaging

1. Performance testing
   Test the hardness, wear resistance, compressive strength and other properties of the finished valve to ensure that it meets the requirements of use.
2. Packaging and delivery
   Valve discs that pass the inspection are packaged to ensure they are not damaged during transportation and then delivered to the customer.

VII. Precautions

1. Raw material purity
   The high purity of alumina powder is the key to ensuring the performance of the valve. The higher the purity, the better the wear resistance and corrosion resistance.
2. Forming pressure
   When dry pressing, it is necessary to precisely control the pressure and holding time to ensure the density and dimensional accuracy of the green body.
3. Sintering temperature
   Excessive sintering temperature may cause grain growth and affect material properties; too low temperature may lead to incomplete sintering.

Through the above customized processing process, high-quality, high-performance alumina ceramic valves can be produced to meet the needs of different industrial scenarios.