This type of high-temperature breathable performance tester is suitable for evaluating the breathable performance of mold shells used in investment casting. It complies with the high permeability method specified in JB/T4153-1999 and the fourth part of the performance test method for mold shells in investment casting as per HB5352.4-2004, namely the determination of breathable performance.

2.Working Principle

1. Melting furnace: The maximum operating temperature is 1000°C.

2. Quartz glass tube: Inner diameter 6mm, outer diameter 8mm, length 400mm.

3. Micrometer caliper: Measuring range is 0mm to 150mm, with an accuracy of 0.02mm.

4. Sample: The shape and size of the sample are shown in Figure 2.

Sample preparation

⑴ Take a celluloid ping-pong ball and a glass tube. Heat one end of the tube to around 250°C. Insert it into the center of the ping-pong ball while it is still hot. Then, use wax (such as beeswax) to firmly bond and seal the ping-pong ball to the glass tube.

⑵ The sample modules should be coated with six layers according to the general shell coating process or in accordance with the specific production process requirements.

⑶ After the sample has dried for 24 hours, it is subjected to calcination. Place it in the furnace at a temperature lower than 100°C, then slowly raise the temperature to 250°C to 300°C, maintain the temperature for a period of time to allow the ball to vaporize, then gradually increase the temperature to 900°C (for silica sol and quartz shell, it is 750°C), maintain the temperature for 2 hours, and then cool down to below 300°C before taking it out of the furnace.

⑷. Sample quantity

The number of valid samples is three.

3.Technical Parameter