How to use and maintain tungsten crucible correctly to prolong its service life?

In the process of using, rapid cooling and heating of tungsten crucible should be strictly avoided. Because the coefficient of thermal expansion of tungsten crucible is small, but frequent sharp temperature changes will still produce large thermal stress and lead to crucible rupture. For example, after the end of melting metal, the crucible which has just been taken out from the high temperature furnace should not be put into cold water to cool down immediately, but it should be allowed to cool down naturally to a certain temperature in the furnace or in dry air, and then carry out the subsequent operation.

When heating the tungsten carbide crucible, the heating speed and the maximum temperature should be reasonably controlled according to the specification of the crucible and the substance to be carried. Generally speaking, the heating speed should not be too fast, and it is recommended that the heating speed should be controlled within a certain range (e.g. 20 - 30℃/min). At the same time, it is important to ensure that the operating temperature does not exceed the rated temperature of the tungsten crucible (it is generally safer to use the crucible below 2600°C). If its tolerance limit is exceeded, the crucible may soften, deform or even melt.

After cooling, clean the tungsten carbide crucible. If there are residues in the crucible, a suitable cleaning method needs to be selected depending on the nature of the residues. For some metal residues, chemical reagents can be used to dissolve and clean them (e.g. dissolving metal oxides with dilute acid), but it is important to note that the chemical reagents should not cause corrosion to the crucible itself. After cleaning, the crucible should be rinsed with water and then dried with clean cloth or paper towel, or put in the drying oven to dry.