Lead-free environmentally friendly tin bars will also produce solder slag during the welding process, which is a normal oxidation phenomenon. The lead-free environmentally friendly tin bar is made of pure tin and trace copper. Antioxidants are added to it. Compared with traditional tin bars, it has high wettability, good fluidity, and is easier to tin. At the same time, the solder joints are bright and full, and there will be no false soldering. It has become the main choice for wave soldering today. So what causes solder slag?
1. The content of tin:
The tin metal in the tin bar is the main component. If the content and purity of tin are not enough, it means that impurities and other elements will increase, which also increases the chance of tin dross overflowing.
2. Furnace temperature control:
Regardless of whether the lead-free environmental protection tin bar has a fixed melting point and operating temperature, if the temperature of the welding furnace is not properly controlled, the oxidation process will be accelerated, and more tin slag will overflow. When the furnace temperature is high or low, black tin ash oxide will continuously appear on the liquid surface of the tin furnace.
Three, tin metal characteristics:
No matter the lead-free environmental protection tin bar is made of tin alloy, tin will chemically react to produce tin dross oxide during the continuous contact with air. In the welding operation, the tin bar changes from solid state to liquid state through high temperature, which will greatly increase the oxidation rate of tin, and the tin dross will increase.
4. Antioxidant elements:
In the production of lead-free environmentally friendly tin bars, anti-oxidant element metals must be added, the purpose of which is to inhibit the air oxidation rate at blast furnace temperature and reduce tin slag. If the amount of antioxidant elements added is not enough, the tin slag will overflow more.