Main components of welding materials:
1, solder wire,organic solvent: ketones, alcohols, esters in one or several mixtures, commonly used ethanol, propyl alcohol, butanol; Acetone, toluene isobutylketone; Ethyl acetate, butyl acetate, etc. As a liquid component.
2, surfactants: halogen containing surfactants strong activity, high welding ability, but because of the halogen ion is difficult to clean, high ion residue, halogen elements (mainly chloride) have strong corrosion.
3, organic acid activator: composed of organic acid dibasic acid or one or several aromatic acids, such as succinic acid, glutaric acid, iconic acid, o-hydroxybenzoic acid, malic acid, succinic acid, etc. Its main function is to remove the oxide on the lead pin and the oxide on the surface of the molten solder, is one of the key components of the flux.
4, anti-corrosion agent: reduce resin, activator and other solid components in high temperature decomposition after the residual substance.
5, co-solvent: prevent activator and other solid components from the solution dissolving trend, avoid the uneven distribution of the activator bad film forming agent: lead foot solder process, coated flux precipitation, crystallization, formation of a layer of uniform film, the residue after high temperature decomposition due to the existence of film agent, can be quickly cured, hardened, reduce the viscosity.
Functions of common flux:
1, the destruction of metal oxide film to clean the solder surface, conducive to solder infiltration and solder joint alloy generation.
2, can be covered in the solder surface, prevent solder or metal oxidation.
3, enhance the activity of solder and welded metal surface, reduce the surface tension of solder.
4. Solder and flux are fused, which can increase the fluidity of solder and further improve the infiltration ability.
5, can accelerate the heat transfer from the soldering iron head to the solder and the surface of the solder.
6, suitable flux can also make the solder joint beautiful.
Characteristics of flux:
1, wetting (lateral flow) : also known as infiltration, refers to the molten solder on the metal surface to form a uniform, smooth, continuous and firmly attached solder layer.
2. Diffusion (longitudinal flow) : accompanied by the wetting phenomenon of the diffusion of molten solder on the welding surface, the solder also appears to the phenomenon of the internal diffusion of solid metal.
Solder wire is a welding product made of tin gold, which is mostly used to assist the welding between flux and product, so that the contact between solvent and product is more comprehensive and improve the welding effect. Therefore, several problems need to be paid attention to in the welding process.
First, the flux flows through the middle part of the tin wire to the surface of the product at high temperature to form a welding chain. Note that if there is a solvent spatter or light smoke phenomenon, the welding temperature should be adjusted in time or auxiliary flux should be added to reduce the speed to ensure the welding effect. Or about to appear fuse phenomenon, to add active agents in time to ensure the product infiltration ability. The final residue after welding to use scientific solvent to eliminate, can not be casually treated.