The process of tin welding
Mainly includes the following aspects.
1) the welding surface is heated to the required temperature.
(2) The solder is heated and melted.
(3) solder soaking the welding surface. The solder, which is melted after heating, is fully spread out along the convex and concave surface of the welded workpiece, that is, wetting.
At this point, it must be ensured that the workpiece and solder surface are sufficiently clean to better perform the wetting process.
In addition, the contact angle between the molten solder and the welded workpiece (also known as the wetting angle) should be 20 ~ 30 degree, ensuring good contact between the two.
(4) Diffusion of molten solder on welding surface. During the welding process, the phenomenon of infiltration and diffusion occurs at the same time. Due to the thermal movement of metal atoms in lattice, when the temperature increases, some metal atoms will be transferred from the original lattice to other lattice, that is, the phenomenon of diffusion occurs. This kind of book spread result that occurs on the metal interface makes the interface of the two contact combine into one and realize the "welding" between the metals.
5) junction and solidification of interfacial layer. After welding, the temperature of the solder joint decreases and the alloy layer is formed at the interface between the solder and the welded workpiece. Alloy layer is one of the most important structural layers in tin welding. There is no or too few virtual welding in alloy layer.
This article is from ALLICDATA ELECTRONICS LIMITED.