Three Tips for Soldering Iron Soldering
Soldering is a science. The principle of electric soldering iron welding is to heat and melt the solid solder wire with a heated soldering iron, and then use the flux to flow into the metal to be welded, and form a firm and reliable solder joint after cooling. .
When the solder is a tin-lead alloy and the soldering surface is copper, the solder first wets the soldering surface, and with the occurrence of wetting, the solder slowly diffuses to the copper metal, forming an adhesion layer on the contact surface between the solder and the copper metal, so that The two are firmly combined. Therefore, solder is completed through three physical and chemical processes of wetting, diffusion and metallurgy.
1. Wetting: The wetting process means that the melted solder flows along the fine bumps and crystallized gaps on the metal surface of the base metal by capillary force, thereby forming an adhesion layer on the surface of the base metal to be welded, so that the solder and the base metal The atoms of the material metal are close to each other, reaching the distance at which the gravitational force of the atoms works.
Environmental conditions that cause wetting: The surface of the base metal to be welded must be clean and free from oxides or contaminants.
Image metaphor: Drop water on the lotus leaves to form water droplets, that is, the water cannot moisten the lotus. Drop water on the cotton, and the water will penetrate into the cotton, that is, the water can moisten the cotton.
2. Diffusion: With the progress of wetting, mutual diffusion between solder and base metal atoms begins to occur. Usually the atoms are in a state of thermal vibration in the lattice lattice, once the temperature rises. The atomic activity intensifies, so that the atoms in the molten solder and the base metal cross the contact surface and enter the lattice lattice of each other. The moving speed and quantity of the atoms are determined by the heating temperature and time.
3. Metallurgical combination: Due to mutual diffusion between the solder and the base metal, an intermediate layer --- metal compound is formed between the two metals. To obtain a good solder joint, a metal compound must be formed between the base material to be welded and the solder. So that the base metal achieves a firm metallurgical bond.
