Graphite crucible manual

Special notes for graphite crucibles:
1. Be careful not to give mechanical impact, do not drop or hit from high places.
2. Do not get wet with water. Store in a dry place.
3. Do not allow graphite cruciblescontact with water after it is melted and dried.
4. Do not aim the flame directly at the crucible (spray to the bottom of the crucible) during use. If there is a noticeable black mark at the bottom of the crucible when it is sprayed.
5. After furnace shutdown, the remaining aluminum and copper materials should be taken out as far as possible, and no residual liquid should be left in the chamber.
6. The use of acid (slag remover, etc.) should be used in an appropriate amount, and excessive use will erode the crucible and cause cracking.
7. Not impact the crucible and not use mechanical force when feed raw materials into it.
Save and carry:
1. The graphite crucible is afraid of water, absolutely must avoid the dampness and the water to drench.
2. Pay attention to surface bruises. Do not place the cruciblesl directly on the floor and place it on the pallet.
3. Do not roll horizontally on the floor. When you push it on the floor, you need to pad the soft cardboard or rag on the floor to avoid bruising the bottom.
4. Pay special attention when handling, do not drop or hit.
Installation:
1. The base of the base must be the same or larger than the crucible’s base diameter of the base, and height of crucible table should be higher than that of nozzle to prevent tthe fire be sprayed into the crucible.
2. The refractory block should be made of round refractory bricks. It needs to be flat and not bent. Do not use half or uneven bricks. It is better to use imported graphite crucible table.
3. The graphite crucible table must be placed at the center of melting, with coke powder, straw ash, or fire-resistant cotton as the mat to avoid sticking the crucible to the crucible table. After the crucible is placed in the middle of the melt, make sure it is horizontal (preferably in horizontal measure).
4. The size of the crucible should be matched with the size of the furnace body. The distance between the crucible and the fusion wall should be appropriate, and it should be at least 40mm.
5. When the nozzle crucible is installed, the contact gap between the bottom of the crucible nozzle and the refractory brick should be reserved about the gap of 30-50MM, and nothing can be cushioned under the bottom. The nozzle and furnace wall should be leveled with refractory cotton.
The furnace wall should have fixed refractory brick (three points) and crucible shall be cushioned with corrugated board about 3mm thick as the hot expansion space after heating.
Preheating drying treatment:
1. Preheat the crucible on the oil stove within 4-5 hours before use, which is helpful for dehumidifying the surface.
2. Place charcoal or wood in the crucible for about 4 hours before using the new crucible, which helps to dehumidify the crucible.
3. The preheating time in the new crucible furnace is as follows:
oil furnace
0 ℃ -300 ℃ slow heating 1H
300 ℃ -800 ℃ slow heating 4H
electric furnace
0 ℃ -200 ℃ slow heating up 4H
200 ℃ -300 ℃ slow heating 4H
300 ℃ -400 ℃ slow heating 4H
400 °C – 600 °C fast heating to maintain 2H
From 400 ℃ to 600 ℃, the temperature increases rapidly and keeps 2H
4. After stopping the furnace, the preheating time of the furnace is as follows: Oil furnaces and electric furnaces: 0 ℃ -300 ℃ slow heating 1H300 ℃ -600 ℃ slow heating 4H600 ℃-rapid heating up to the required degree
a. Electric furnace: the best way to stop work is to keep the temperature around 600 ℃; if not, the soup should be scooped out as far as possible, not to stay in the crucible too much; if power failure, the material should be taken out quickly.
b. Oil furnace: After the furnace is stopped, the soup should be kept as clean as possible. The cover of the furnace and the vents of the furnace should be covered well, and the remaining temperature of the furnace should be kept away from moisture.
5. Feeding: When the first furnace is used, first add the scrap (small material) and then add the block material, and then use pliers to tighten and gently put it into the crucible. You can’t add too much at one time to avoid crushing the crucible.
A. Oil furnace: 300 °C can be added later;
B. electric furnace:
a. 200 °C – 300 °C began to add small materials, 400 °C after the slowly adding block material, such as the production of continuous feeding do not add to a fixed position, so as not to Causes oral oxidation.
b. Dedicated to heat preservation electric furnace. Before stopping the furnace, it must be preheated to 500°C to pour aluminum soup.
Precautions in use:
To be gently, not vigorously and placed in a crucible to avoid crashed through the crucible when feeding.
2. The 24-hour non-stop service life will be longer. When the furnace is shut down, the melting soup in the bowl must be cleared to prevent the molten soup from solidifying and then reheating. When the heat is applied, it will expand, affecting the life of the bowl or even breaking the bowl.
3. Melting Aids: The use of additives (FLLUX) for the melting of aluminum alloys and borax for copper alloys requires a small amount for avoid erosion of the crucible walls.
Auxiliaries need to be dissolved in a minimum of 8 minutes when the aluminum metal is dissolved into the soup. Lightly mix in the medium and stir it to avoid adhesion to the inner wall of the crucible.
*Aluminum alloy auxiliaries containing more than 10% NA are required for special materials.
4. After the daily work is completed, when it is still red, please remove the metal material attached to the wall and clean it to prevent the residue from affecting the heat transfer and increasing the dissolution time, resulting in thermal expansion and bursting.
5. It is recommended to use the crucible smelting aluminum alloy for about two months (melting copper alloy weekly) to check whether the surface is abnormal or not, and the furnace can be cleaned and the crucible turned in the same time. This operation is helpful for prolonging the service life of the crucible.