What should I do if the vacuum furnace annealing is severely oxidized?

In the vacuum annealing furnace, the copper strip is oxidized, indicating that the vacuum furnace is leaking.

1. Check whether the working vacuum of the vacuum pump is normal. Use a vacuum gauge to check the vacuum at the inlet of the vacuum pump to see if it can reach the ultimate vacuum of the pump. If not, change the oil, or repair, and never change the pump.

2. Use a leak picker to pick up leaks in the vacuum furnace. If there is no leak detector (leak detector is very expensive), use acetone (industrial alcohol) to pick up the leak, the general leak detection rate is 0.2Pa/h, there should be no problem.