Copper wire fracture reason: copper wire in the solder interface fracture, cross section is round (no deformation marks), the section is uneven, who knows the cause of the fracture?!
The temperature is low and the time is short. Tin may be difficult. The boss said: "that will raise the temperature a little bit more," the worker said: "with a good quality solder ah, add a little cerium ah, with a good effect of a bit of flux ah!"....... Game final result, also ask landlord to tell ah, ha ha, want to know about society.
Tin dipping temperature, i.e. the temperature you don't tin is too high, not too long time dipping tin bronze layer will be formed, otherwise relatively thick, more like bronze wire, more easily broken. Low temperature, not only to save energy, the boss happy, is environmentally friendly, lead steam evaporated tin less workers being exploited at the same time, can be slightly less toxic, favorable to the satisfaction of all, harmonious.
The reason is that when the copper wire is combined with the solder, the alloy layer is formed on the bonding surface of the two metals - the bronze layer. I think we all know that the bronze, both hard and brittle, impregnated with a copper tin because of high strength, not easy to break; without a tin dipping, because copper flexible, is not easy to break; then, just in a combination of broken, because the bronze layer has been formed here the lack of strength and lack of supporting thick tin layer.
