Introduction to the difference between the power of electric soldering irons
In the process of electrical repair, an electric soldering iron is an essential tool, but many maintenance personnel who have just come into contact with soldering irons do not know what standards to use to select the power of the soldering iron during the welding process. Often, one soldering iron dominates the world. The most direct consequence is that the soldering effect is not ideal due to not paying attention to the power size of the soldering iron.
The electric soldering iron used has excessive power, which can easily burn out components (usually when the junction temperature of the transistor exceeds 200 ℃) and cause printed wires to detach from the substrate; The power of the soldering iron used is too low, the solder cannot be fully melted, the flux cannot evaporate, the solder joints are not smooth and firm, and it is easy to produce virtual soldering. Generally, it is used for soldering integrated circuits, printed circuit boards, CMOS circuits, decorative transistors, IC recorders, televisions, and conducting ordinary circuit experiments. It is generally recommended to use 20W. For repairing vacuum tube machines such as gallbladder machines and old instruments, 35W is recommended. For external heating type machines, 45W is recommended. For soldering the wiring of large transformers and grounding main lines on metal substrates, internal heating type 50W and external heating type 75W are used. If welding metal materials, an external heating soldering iron with a power of over 100W should be selected. If conditions permit, amateur radio enthusiasts can equip themselves with a 2OW internal heating type, a 35W internal or external heating type, and a 150W external heating type soldering iron, which can basically meet various welding needs.
The solder we use is generally divided into two types: lead solder and lead-free solder, but the most commonly used is lead solder, which has a composition of 63% tin, 37% lead, and a melting point of 183 ℃. Lead free solder has a composition of 99% tin and a flux of about 1%, with a melting point of 227 ℃. The advantages of lead soldering are low melting point, easy soldering, and low price, but it is not environmentally friendly. Lead is harmful to the human body, so after soldering is completed, it is necessary to wash hands carefully. During the soldering process, it is best to wear a mask or in a bright place to ensure a certain distance between the head and the workpiece. With the increasing awareness of environmental protection among people, lead-free soldering is now used for machine welding in factories. Due to the high melting point of lead-free solder, it is not difficult to understand why it is sometimes difficult to melt solder when repairing imported electrical appliances.
