Vacuum annealing furnaces are mainly used for stainless steel components such as plumbing parts, expansion pieces, and medical devices. These stainless steel products undergo bright annealing, solution treatment, demagnetization, and quenching under protective gas. The process ensures a bright surface, prevents oxidation and decarburization, and offers high efficiency, low energy consumption, and easy operation.
However, blockages sometimes occur. The main causes are:
1. Low-Temperature Corrosion in the Air Preheater
- Heat-exposed surfaces become wet and rough.
- Dust accumulates more easily, worsening blockage.
2. Incomplete Drying after Cleaning
- Cleaning the economizer or air preheater with water leaves residual moisture.
- Starting the furnace before complete drying causes further dust accumulation and blockage.
3. Foreign Materials Entering the Air Preheater
- Insulation materials from the quenching furnace or other debris fall into the air preheater.
- This obstructs gas flow and increases dust deposition, leading to blockage.
4. Water Leakage in the Economizer
- If water leakage occurs and is not addressed promptly, a water film forms on the preheater surface.
- Fly ash mixes with the water film, forming a mud-like substance that blocks the tubes.
5. Small Tube Spacing in Horizontal Air Preheaters
- In the low-temperature section, narrow spacing between tubes allows dust to “bridge” across tubes.
- This creates blockages in the furnace.
Tip: Regular maintenance, monitoring of preheaters, and careful operation can significantly reduce blockages and extend the service life of the vacuum annealing furnace.