Tying the bottom of the furnace: the thickness of the bottom of the furnace is about 280mm, and it is filled with sand four times. The uneven density should be prevented when using the knotting material manually, and the furnace village after baking and sintering is not dense. Therefore, it is necessary to strictly control the feeding thickness, the general packing thickness is not greater than 100mm/ time, the furnace wall is 0 within 60mm, slowly rotating around the furnace and changing positions, uniform force, so as not to cause uneven density.

The crucible die can be placed by scraping the bottom of the furnace when the knot reaches the required height. In this regard, it should be noted that the crucible die is concentric with the induction ring, the upper and lower adjustment is vertical, the pattern is closely combined with the bottom of the furnace as far as possible, and the surrounding gap is adjusted to be equal with three wooden wedges, and the middle weight is pressed on to avoid the displacement of dry material when the furnace wall is knotting.

Tie the furnace wall: the thickness of the furnace lining is 110-120mm, add dry knotting material in batches, the cloth is uniform, the thickness of the filler is not more than 60mm, tie for 15 minutes (manual knotting), until it is flush with the upper edge of the induction ring. When the crucible die is not taken out after tying, it plays induction heating role during drying and sintering.

Baking and sintering:

In order to obtain the dense binding structure of the lining, the baking and sintering process is roughly divided into two stages:

Baking stage: the furnace body is heated to 100 ° C at the speed of 50 ° C /h, and the heat is kept for 2h, and the furnace body is heated to 300 ° C at the speed of 100 ° C /h, and the heat is kept for 2h, in order to completely eliminate the moisture in the furnace lining.

Sintering stage: heating to 900℃ at 200℃/h, holding for 2h, heating to 1200℃ at 100℃/h, holding for 2h,... Furnace copper water 1400-1650 degrees, heat for 1 hour, control the heating rate, to prevent cracks.

Note when heating up:

20℃-100℃, rise 50℃ per hour, 1.6 hours to 100℃, constant temperature for 1 hour.

100℃-300℃, 100℃ per hour, 2 hours to rise to 300℃.