NOCOLOK brazing process
Release time:
2022-12-11
【Summary Description】 Brazing definition: a welding method in which a metal material with a melting point lower than that of the base metal is used as a brazing material, and the base metal is wetted with a liquid brazing material, so that the interface gap between the workpiece and the base metal is filled and diffused. When brazing, only the brazing filler metal melts, while the base metal remains solid, which requires the melting point of the brazing filler metal to be lower than the base metal, and its composition is also different. The molten solder is drawn into and held in the interstices of the base metal by wetting and capillary action, and the interdiffusion between the liquid solder and the solid base metal forms a metallurgical bond. Introduction of aluminum brazing; The brazing of aluminum began in the early 1930 s. Today, many different brazing techniques have been employed. In the brazing equipment, atmosphere furnace brazing, vacuum brazing and immersion brazing accounted for a large part. The characteristics of aluminum brazing: In order to make the brazing successful, the surface of the brazed joint must be clean, and the surface must not be oxidized at the brazing temperature. Aluminum is easily oxidized in the air and during the welding process, and the aluminum oxide (Al2O3) produced has a high melting point, is very stable, and is not easy to remove. (If the temperature exceeds 250°C, high-temperature oxides will form on the surface of aluminum, which are difficult to remove by Norlock solder.) The oxide film hinders the melting and fusion of the solder, and the oxide film accounts for a large proportion, which is difficult to surface, and is prone to defects such as slag inclusion, incomplete fusion, and incomplete penetration. The oxide film on the aluminum surface and the adsorption of a large amount of water are easy to cause pores in the weld. When welding, the oxide film on the surface should be removed. (The flux reacts with the oxide and displaces the oxide, thereby preventing the weldment from contacting the furnace air, causing the solder to melt and be drawn into the weld by capillary action.) Just as oil surface watering will form water droplets due to the effect of surface tension, the brazing filler metal on the oxide film cannot be uniformly combined with the base material (base material), so a poor brazing surface will be formed.
Brazing definition: a welding method in which a metal material with a melting point lower than that of the base metal is used as a brazing material, and the base metal is wetted with a liquid brazing material, so that the interface gap between the workpiece and the base metal is filled and diffused.
When brazing, only the brazing filler metal melts, while the base metal remains solid, which requires the melting point of the brazing filler metal to be lower than the base metal, and its composition is also different. The molten solder is drawn into and held in the interstices of the base metal by wetting and capillary action, and the interdiffusion between the liquid solder and the solid base metal forms a metallurgical bond.
Introduction of aluminum brazing;
The brazing of aluminum began in the early 1930 s. Today, many different brazing techniques have been employed. In the brazing equipment, atmosphere furnace brazing, vacuum brazing and immersion brazing accounted for a large part.
The characteristics of aluminum brazing: In order to make the brazing successful, the surface of the brazed joint must be clean, and the surface must not be oxidized at the brazing temperature. Aluminum is easily oxidized in the air and during the welding process, and the aluminum oxide (Al2O3) produced has a high melting point, is very stable, and is not easy to remove. (If the temperature exceeds 250°C, high-temperature oxides will form on the surface of aluminum, which are difficult to remove by Norlock solder.) The oxide film hinders the melting and fusion of the solder, and the oxide film accounts for a large proportion, which is difficult to surface, and is prone to defects such as slag inclusion, incomplete fusion, and incomplete penetration. The oxide film on the aluminum surface and the adsorption of a large amount of water are easy to cause pores in the weld. When welding, the oxide film on the surface should be removed. (The flux reacts with the oxide and displaces the oxide, thereby preventing the weldment from contacting the furnace air, causing the solder to melt and be drawn into the weld by capillary action.)
Just as oil surface watering will form water droplets due to the effect of surface tension, the brazing filler metal on the oxide film cannot be uniformly combined with the base material (base material), so a poor brazing surface will be formed.
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