Analysis of crack in graphite crucible

Problem description	Cause analysis
1.longitudinal crack
1) After the graphite crucible is used for a long time, longitudinal cracks appear in the crucible wall, and the wall of the crack is thin.	1) The graphite crucible is about to reach the end of its service life, and the crucible wall will become thinner and cannot withstand excessive force.
2)The first time (or nearly new) has a crack on the bottom edge and runs through the bottom of the crucible.	2) Place the cooled crucible in a hot heat, or when the crucible cools, heat the bottom of the crucible too quickly. The damage is generally accompanied by glaze peeling.
3) Longitudinal cracks extending from the top edge of the graphite crucible	3) Caused by too fast heating of the graphite crucible, especially when the bottom and bottom edges of the crucible are heated much faster than the top. The intrusion operation at the top edge of the crucible is also likely to cause this damage. Unsuitable pliers or knocks on the top edge can also cause scratches and visible damage to the top edge of the pry.
4) Longitudinal cracks on the sides of the graphite crucible (the crack does not extend to the top or bottom of the crucible)	4) Normally caused by internal pressure. For example, the cooled wedge-shaped cast material is placed laterally in the crucible, and the wedge-shaped cast material will cause the damage when it is thermally expanded.
2 transverse crack
1)Close to the bottom of the graphite crucible (which may cause the bottom of the crucible to fall off)	1)It may be caused by a hard object impact, such as casting into a crucible or hitting the bottom with a hard object such as an iron bar.
2)About half the position of the graphite crucible	2) The reason may be that the crucible is placed on the slag or on the unsuitable crucible base. When the crucible is removed, if the pinch clamp is clamped to a position that is too high and the force is too great, it will result in Cracks in the surface of the jaw below the tongs
3) when using a crucible with a graphite crucible tip, there is a transverse crack at the bottom of the crucible tip	3) the crucible is not properly installed. When the new crucible is installed, if the refractory soil is tightly squeezed under the crucible tip, during use, When the crucible is cooled and contracted, the stress point will be concentrated at the tip of the crucible and cracks will occur.
3 star cracks
1) At the bottom of the crucible	1) Caused by thermal expansion
2) The side of the crucible	2)Usually caused by the expansion of the wedge after heating
4 holes/break
1)A large hole appeared in the wall of the crucible that had not yet thinned	1)Mostly caused by a heavy blow, such as: throwing an ingot into a pot
2)holes	2)It is usually due to a crack that requires a pause and a crack.

作者： d.zhao@xrdgraphite.com

Related Posts