Reasons for cracking at the bottom of the molten graphite crucible

The cracking at the bottom of the molten graphite crucible may be caused by various reasons. Firstly, there may be coke or slag sticking to the bottom of the crucible. When the crucible is placed on a hard ground, these substances may cause the crucible bottom to protrude upwards and produce cracks. Secondly, slag expansion may also cause cracking at the bottom of the crucible. Working for a long time above 1460 ℃ may cause the surface of the crucible to turn green and begin to soften, leading to cracking. In addition, when a new crucible is first used, its bottom or lower edge may also detach due to issues during the manufacturing process, which is also a possible cause of bottom cracking.

To avoid cracking at the bottom of the crucible, it is necessary to carefully inspect the crucible before use to ensure that its appearance is intact, free of cracks and damage, and the interior is dry and free of debris. During use, materials should be added according to the capacity of the crucible to prevent metal from expanding and cracking the crucible due to thermal expansion. At the same time, when removing the molten metal after melting, a spoon should be used to scoop it out, and the use of calipers should be minimized as much as possible to avoid applying excessive impact force to the crucible.

If there is a crack at the bottom of the crucible, it should be replaced as soon as possible to avoid the crack continuing to expand and affecting the experimental results. In emergency situations, graphite repair agents can be used to repair minor cracks, but after repair, attention should be paid to whether the structure of the crucible is deformed to prevent the recurrence of cracks.

In addition, the storage environment of the crucible is also an important factor affecting its service life. Graphite crucibles should be stored in a dry, ventilated, and dark place, avoiding direct sunlight and humid environments. When storing, place the graphite crucible on a wooden frame or soft pad to reduce external impact.

In summary, in order to extend the service life of the molten graphite crucible and avoid bottom cracking, a careful inspection should be carried out before use, paying attention to the usage method and storage environment, and replacing or repairing it in a timely manner when cracks are found.