1. Whether the annealing temperature reaches the specified temperature
The pipe fittings are generally heat treated with solid solution, and the temperature standard is 1040≤1120℃ (Japanese code). Through the investigation of the survey hole of the annealing furnace, incandescent lamps should be used for the flange pipe fittings in the annealing zone, but there should be no softening and sagging phenomenon.
2. Furnace body sealing
The bright annealing furnace should be closed and isolated from the outside air; if you choose hydrogen as the maintenance gas, you only need to open an exhaust port. Soap water can be used at the junction of the annealing furnace to determine whether it falls off. The place where the annealing furnace enters the tube and outside the tube, this kind of local sealing ring is particularly easy to wear, and is often checked and replaced.
3. Maintain gas pressure
In order to prevent micro-leakage, the maintenance gas in the furnace should maintain a certain positive pressure. For hydrogen maintenance gas, 20 Kbar is generally required.
4. Annealing atmosphere
Generally, pure hydrogen is used as the annealing atmosphere, and the air purity is better than 99.99%. If the other part of the atmosphere is inertial gas, the purity can be slightly lower, but it cannot contain too much oxygen and water vapor.
5. Furnace steam
On the one hand, check whether the furnace data is drilled, and the furnace data needs to be dried. On the other hand, whether there are too many water stains in the flange pipe fittings, especially when the flange pipe fittings have holes, do not leak water, otherwise the gas in the furnace will be completely destroyed.