Daily maintenance of box type atmosphere annealing furnace

As the core equipment for metal heat treatment, the daily maintenance of the box type atmosphere annealing furnace directly affects the equipment life, process stability, and production safety. The following is a systematic summary of maintenance points and precautions from five dimensions: cleaning and maintenance, mechanical inspection, electrical maintenance, pneumatic maintenance, and safety protection:

1. Cleaning and maintenance
Furnace cleaning
Frequency: After processing each batch or once a week (depending on usage frequency).
method:
Use a vacuum cleaner or soft bristled brush to remove residue, oxides, and dust from the furnace.
Avoid using sharp tools to scrape the inner wall of the furnace to prevent damage to refractory materials.
Case: A certain enterprise’s failure to clean the furnace oxide scale in a timely manner resulted in scratches on the surface of the workpiece, leading to a 15% increase in scrap rate.
Seal cleaning
Key parts: furnace door sealing strip, observation window sealing ring.
Method: Wipe the surface of the seal with a damp cloth to remove oil stains and impurities, and check for cracks or aging.
Attention: If the sealing strip is damaged, it needs to be replaced immediately, otherwise it may cause atmosphere leakage and affect the quality of the process.
external cleaning
Frequency: Daily or per shift.
Method: Use a dry cloth to wipe the dust on the surface of the furnace body and avoid corrosive liquids from contacting the outer shell.

2. Mechanical component inspection
Furnace door transmission system
Inspection content:
Chain/gear lubrication condition, add high-temperature grease if necessary.
Whether the furnace door opens and closes smoothly, and whether there is any jamming or abnormal noise.
Case: A certain enterprise’s furnace door chain was not lubricated in a timely manner, resulting in wear and tear of the transmission gear and an increase of 5000 yuan in maintenance costs.
Fan and air duct
Inspection content:
Check if the fan blades are deformed or dusty, and clean or replace them if necessary.
Check if the air duct is blocked and ensure even airflow.
Impact: Fan failure can cause uneven temperature inside the furnace, affecting the consistency of workpiece performance.
Bracket and tooling
Inspection content: Check whether the bracket is deformed and whether the fixture is clean and free of residue.
Suggestion: Regularly replace the deformed bracket to avoid local overheating caused by unstable placement of the workpiece.

3. Electrical system maintenance
Heating element inspection
Frequency: Once a month.
method:
Visually inspect the heating wire for uneven redness, breakage, or oxidation.
Measure the resistance value with a multimeter to determine if it is aging.
Case: A certain enterprise failed to replace the oxidation heating wire in a timely manner, resulting in high local temperatures and scrapped workpieces.
Temperature control system calibration
Frequency: Once every quarter.
method:
Use a standard thermometer to calibrate the temperature inside the furnace, with an error of ≤± 5 ℃.
Check if the over temperature alarm device is sensitive.
Risk: Temperature control deviation can lead to substandard workpiece performance and even cause safety accidents.
Electrical connection inspection
Key parts: power cord, control cabinet terminal block, grounding wire.
Method: Tighten loose connections and check if the insulation layer is damaged.
Attention: Electrical faults may cause serious accidents such as short circuits and fires.

4. Maintenance of pneumatic system
Gas pipeline inspection
Frequency: Before daily use.
method:
Check if there is any air leakage at the pipeline connection (soap water detection).
Ensure that the valve switch is flexible and free from any jamming.
Case: An explosion accident occurred in a certain enterprise due to the failure to detect a hydrogen pipeline leak in a timely manner.
Gas filter cleaning
Frequency: Every 3 months or according to gas purity requirements.
Method: Disassemble the filter, remove impurities, and replace the filter element.
Impact: Filter blockage can lead to insufficient gas flow and affect the purity of the atmosphere.
Gas quality monitoring
Method: Regularly check the gas purity (such as hydrogen purity ≥ 99.99%) to ensure compliance with process requirements.
Suggestion: High purity gases require the use of specialized pressure reducing valves and flow meters.

5. Security protection and records
Safety device inspection
Key devices:
Emergency stop button: Test once a month to ensure proper functionality.
Gas leak alarm: Calibrate once every quarter, and the sensitivity should meet the standard.
Case: A company experienced a dangerous accident due to the failure of a gas leak alarm, which failed to detect a hydrogen leak in a timely manner.
Maintenance records
Content: Record maintenance time, inspection items, replacement of parts, abnormal situations, and handling measures.
Function: Facilitating the traceability of equipment status and developing preventive maintenance plans.
Operator training
Content: Equipment operation specifications, safety precautions, emergency response procedures.
Suggestion: Organize safety training every six months to strengthen personnel awareness.

6. Summary
The daily maintenance of the box type atmosphere annealing furnace should follow the principle of “prevention first, timely maintenance”, and ensure long-term stable operation of the equipment through systematic cleaning, inspection, lubrication, and calibration. The key points include:
Sealing maintenance: prevent atmosphere leakage and ensure process quality.
Electrical safety: Avoid safety hazards such as short circuits and electrical leakage.
Pure gas path: Ensure gas purity and stable flow rate.
Record traceability: Establish comprehensive maintenance records to support equipment lifecycle management.
Through scientific maintenance, the equipment failure rate can be reduced by more than 30%, the service life can be extended by 2-3 years, and the product qualification rate and production efficiency can be improved.