Advantages and Disadvantages of Brazing
– Allows tighter control over tolerances
– Produces a clean joint without the need for secondary finishing
– Can join dissimilar metals and non-metals
– Produces less thermal distortion than welding
– Cost-effective for complex and multi-part assemblies
– Lack of joint strength compared to welded joints
– Potential damage under high service temperatures
– Requires high degree of base-metal cleanliness
– Joint color may differ from base metal, creating an aesthetic disadvantage
– Soft filler metals used may result in lower joint strength compared to base metal
Base Metal Preparation for Brazing
– Joint clearances of 0.03 to 0.08mm (0.0012 to 0.0031in) recommended
– Joint clearances of around 0.6mm (0.024in) are not uncommon in some operations
– Chemical cleaning and abrasive/mechanical cleaning are two main methods for preparing parts
– Proper surface roughness is important for optimal wetting
– Cleanliness of brazing surfaces is crucial to prevent poor wetting and flow
Temperature and Time Considerations in Brazing
– Brazing temperature should be above the melting point of the filler metal
– Temperature selection influenced by minimizing heat effects on the assembly
– Temperature selection influenced by minimizing filler metal/base metal interaction
– Temperature selection influenced by maximizing the life of fixtures or jigs used
– Time considerations primarily affect the extent of alloying and wetting action
Production Processes and Cost Considerations
– Production processes aim to minimize brazing time and associated costs
– Higher temperatures may be selected to accommodate design factors or control metallurgical effects
– Proper surface preparation and cleaning contribute to efficient and cost-effective brazing
– Automation is easily achievable in brazing due to less sensitivity to process parameter variation
– Coating or cladding can be applied to brazed joints for protective purposes
Other Details
– None Source: https://en.wikipedia.org/wiki/Brazing
Brazing is a metal-joining process in which two or more metal items are joined by melting and flowing a filler metal into the joint, with the filler metal having a lower melting point than the adjoining metal.
Brazing differs from welding in that it does not involve melting the work pieces. Brazing differs from soldering through the use of a higher temperature and much more closely fitted parts than when soldering. During the brazing process, the filler metal flows into the gap between close-fitting parts by capillary action. The filler metal is brought slightly above its melting (liquidus) temperature while protected by a suitable atmosphere, usually a flux. It then flows over the base metal (in a process known as wetting) and is then cooled to join the work pieces together. A major advantage of brazing is the ability to join the same or different metals with considerable strength.
