Fault: The cold ingot is horizontally crowded in the graphite crucible, and when heated and melted, the ingot expansion will crush the graphite crucible, and when the feeding method is wrong, the top edge and side wall of the graphite crucible are simply damaged.
The correct method: the large ingot should be put vertically into the crucible, to make sure that there is a satisfactory open space between the ingot and the crucible, and use the clamp to be careful to put the ingot and heavier materials into the graphite crucible.
Notes:
Put the crucible into the furnace, it is best to wait for itself to be red, first put a little small broken metal material at the bottom of the crucible, and then put the metal ingot (it is necessary to bake on the edge of the furnace before the metal ingot goes off the pot), so as not to put the cold ingot directly into the pot, causing the crucible to explode when it is cold. Moreover, it is necessary to ensure that these materials have a satisfactory expansion space when heated in the crucible, otherwise the graphite crucible will simply be squeezed and cracked.
It is necessary to put the baked metal ingots into the pot slowly and vertically. If it is placed horizontally, the metal ingot is simply squeezed through the hot expansion. It is necessary to be very careful when feeding into the crucible, and it is best to put the ingots and heavier materials into the graphite crucible with clamps. Do not use the pouring method to feed, the edges and corners of the ingot may crack the crucible.
In the process of use, when the metal water in the pot is too little, do not add too much material at one time, so that the metal water in the pot is cold and condensed, and then when the temperature rises again, the metal is thermally expanded and breaks the crucible.