CAB Maintenance Tips

Improving Muffle Service Life

One of the most critical components of a CAB Furnace is the braze muffle. A muffle is constructed from high grade stainless steel for durability, but will eventually need to be replaced due to corrosion. The key to extending the life of the muffle is to conduct proper maintenance of the furnace system. Every company wants to reduce cost for replacements/spare parts while maintaining a high quality operation. This can be accomplished by minimizing the volume of flux being sprayed onto the aluminum heat exchangers and ensuring the furnace atmosphere is within the recommended range, both in dew point and O₂. This helps to reduce the volume of HF which is formed during the brazing process when water vapor is present. During brazing, the fluoride component of the flux volatilizes (KAlF4) and can react with moisture present in the furnace to produce HF. The following procedures will extend the life of a muffle and should be incorporated into your maintenance schedule:

• Limit the formation of HF inside the muffle chamber
• Clean the inside of the muffle at least once a year
• Utilize the required flow of nitrogen to maintain a high quality atmosphere
• Replace the entrance and exit curtains when signs of wear are noted

For more information on new and replacement muffles follow this link:  http://www.secowarwick.com/alumbraze/bulletins/furnacemuffle.htm

The latest design, materials and equipment specifications should be obtained from the company before any reliance is placed on the enclosed since changes may occur due to product improvement.