Graphite crucible used six or seven times on how bad?
And the solution in the barrier, is it right?. The main check temperature should not be too fast, rapid cooling.
May be the temperature contrast is too large, cold, plus hot pot Meng, after use, and suddenly cooled, in the case of expansion and contraction, easily damaged.
It should be that the graphite reacts with the oxygen in the air when it is heated, and is corroded once every time
