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Brazing knowledge summary(7)

Jan 28, 2019

Solder selection editor

(1) The solder should have a suitable melting temperature range, at least tens of degrees lower than the melting temperature of the base material.

(2) At the brazing temperature, it should have good wettability to ensure that the gap between the brazing seams is fully filled.

(3) The solder and the base material should have a diffusion effect to form a strong bond.

(4) The brazing material should have a stable and uniform composition to minimize the loss of alloying elements during the brazing process.

(5) The brazed joint obtained shall meet the technical requirements of the product and meet the requirements of mechanical properties, physical and chemical properties and performance.

(6) The economics of the brazing filler metal is better. Minimize or contain rare metals and precious metals. It should also ensure that the productivity of brazing is high.

(7) The brazing material should have a processing deformation ability to facilitate various shapes.

Second, the classification of solder

1. According to the melting temperature range of the solder

(1) A solder having a melting point of lower than 450 ° C is called a solder such as a gallium base, a ruthenium base, an indium base, a tin base, a lead base, a zinc base or the like.

(2) Solder having a melting point higher than 450 ° C is called brazing filler metal (commonly known as refractory brazing filler metal) such as aluminum-based, magnesium-based, copper-based, silver-based, manganese-based, gold-based, nickel-based, palladium-based, and Chinky. .

2. According to the main alloying elements of the solder

The brazing filler metal can be divided into tin base, lead base, aluminum base and the like according to its main alloying elements.

3. According to the shape of the bran

The brazing material can be classified into a wire, a rod, a sheet, a foil, a powder or a special shape brazing material (for example, a ring-shaped solder or a paste-like solder).

Note editing

basic method

1. Use a trowel, scraper or wire brush to remove oil from the weld.

2. Clean the soldering iron and brush the copper oxide with a wire brush.

3. Apply solder to the soldering area.

4. Dip the solder with a heated soldering iron, stop it for a while at the soldering site, and let the soldering piece heat up, then slowly move it so that the solder flows evenly into the weld to form a smooth and smooth bead.

5. When the weld is long, the weldment can be fixed, pressed and coated with flux, first by spot welding, and then all welds.

Safety Precautions

1. The soldering iron should be stabilized to prevent it from falling out, so as not to cause fire or burns.

2. When using a soldering iron, first pay attention to whether the power supply voltage and the soldering iron voltage are consistent. When it is inconsistent, it is not allowed to use. After power-on, you cannot leave it casually. Disconnect the power after use.

3. When testing the soldering iron temperature, use solder test, do not touch with your hands to prevent burns.

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