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Brazing technology and introduction
Brazing is a method of using a metal material with lower melting point than the base metal as a brazing material, heating the weldment and the brazing filler metal to a temperature higher than the melting point of the brazing filler metal, but lower than the melting point of the base metal, wetting the base metal with the brazing filler metal, filling the joint gap, Mutual diffusion to achieve connecting the weldment.
Classification of brazing methods
The quality of the brazed joint depends on the chosen brazing method, brazing material (brazing flux, solder, etc.) and process parameters. According to different characteristics and standards, brazing methods have the following classification.
①According to the melting point of the solder used can be divided into soldering and brazing, solder melting point below 450 ℃ is called the soldering, higher than 450 ℃ is called brazing.
②According to the level of brazing temperature can be divided into high-temperature brazing, intermediate temperature brazing and low temperature brazing temperature, the temperature is divided relative to the melting point of the base metal. For example, to steel, the heating temperature higher than 800 ℃ is called high-temperature brazing , between 550 ~ 800 ℃ is called the intermediate temperature brazing, heating temperature lower than 550 ℃ is called low-temperature brazing; but for the aluminum alloy , the heating temperature higher than 450 ℃ is called high temperature brazing, between 300 ~ 450 ℃ is called intermediate temperature brazing, the heating temperature lower than 300 ℃ is called low temperature brazing.
③According to the type of heat source and heating method can be divided into flame brazing, furnace brazing, induction brazing, resistance brazing, dip brazing, gas phase brazing, INSiron brazing and ultrasonic brazing.
④According to the way of removing the base metal oxide film can be divided into flux brazing, flux-free brazing,self-fluxing brazing, gas protection brazing and vacuum brazing.
⑤According to the characteristics of the joints formation can be divided into capillary brazing and non-capillary brazing. The liquid solder relies on the capillary action to fill the brazing seam. This is called capillary brazing; the capillary action is called non-capillary brazing, which can not play a major role in the formation of the brazed joint. Contact reaction brazing and diffusion brazing is the most typical non-capillary brazing process.
⑥According to the different connected base metal or solder can be divided into aluminum brazing, stainless steel brazing, titanium alloy brazing, high temperature alloys brazing , ceramic brazing, composite materials brazing, and silver brazing, copper brazing, etc.