Welding Materials For High Current Terminals And Electrical Connectors

Solder for connector is also called solder. Its melting point is lower than that of the metal to be welded. When melting, it can form alloy on the surface of the metal to be welded and connect the metal to be welded. In the general high current terminal assembly, the main use of tin lead solder, commonly known as solder, it is a kind of lead tin alloy. Lead (PB) and tin (SN) melt to form alloy, which has a series of advantages that lead and tin do not have:

1) the melting point is low, and the melting point of lead tin alloy with different composition is lower than that of lead and tin, which is conducive to welding.

2) The mechanical strength of Pb Sn alloy is better than that of Pb and Sn.

3) The surface tension is small, the viscosity is decreased, and the liquid fluidity is increased, which is conducive to the formation of reliable joint during welding.

4) The oxidation resistance of lead remains in the alloy, which reduces the amount of oxidation during melting. 2. Eutectic solder eutectic solder is a Pb Sn alloy with composition of Pb 38.10-10 and Sn 61.9%, which is one of the best properties of Sn Pb solder.

It has the following advantages:

1) the melting point is low, which can reduce the heating temperature when welding electrical connector, and prevent the damage of plug-in components.

2) The melting point and freezing point temperature are the same, both of which are 183C | C, which can make the solder joint rapidly solidify, and will not cause the solder joint crystallization porosity and strength reduction due to the long time interval of semi melting state. This is of great significance for automatic welding because vibration is inevitable in the transmission of automatic welding.

3) Good fluidity and low surface tension are beneficial to improve the quality of solder joint.

4) High mechanical strength, good conductivity. In practical application, it is impossible and unnecessary to control the proportion of lead and tin in theory. Generally speaking, the solder with Pb 400 - / O and Sn 60% is called eutectic solder. Its solidification point and melting point are not single 183 ℃, but in a certain range. This is economical in engineering.

The physical properties and impurities of solder affect lead tin alloy with different proportion, and the physical properties are different. The results show that the tensile strength and shear strength of high current terminal with about 60% tin are better. Different tin content of electrical connector leads to different properties and uses of soldering tin, which should be selected according to the needs. General electronic welding, special connector is manual soldering iron tin, multi-purpose eutectic solder.