1. Factor of welding current
Since the heat generated by resistance is proportional to the square of the current passed, welding current is an important factor in generating heat. The importance of welding current is not only the size of the welding current, the current density is also very important.
Nucleus:It is the part of the metal that solidifies after the joint is molten during lap resistance welding.
2. Factor of pressurization
Pressurization during the welding process of the seam welder is an important factor in the generation of heat. Pressurization is the mechanical force applied to the welded part. Through pressurization, contact resistance is reduced to make the resistance value uniform, prevent local heating during welding, and make the welding effect uniform.
3. Factor of resistance welding time
The resistance welding time is also an important factor in the generation of heat. The heat generated by energizing is first transferred through conduction. Even if the total heat is certain, the temperature at the weld is different due to the different energizing time, and the welding results are different.
4. Factor of current waveform
The combination of heating and pressurization in time is very important for the seam welder, so the temperature distribution at each moment of the welding process must be appropriate. Depending on the material and size of the weldment, make it flow a certain current for a certain time. For heating of the contact area, a slow pressurization can cause local heating and deteriorate the seam welder's welding effect. In addition, if the current is stopped sharply, the weld area will suddenly cool down, leading to cracks and material embrittlement. Therefore, a small current should be passed before and after the passage of the main current, or pulses should be added to the upper and lower currents.
5. Factor of material surface condition
Contact resistance and the heating of the contact part are directly related factors. When pressurization is certain, the contact resistance determines the state of the surface of the weld, i.e., after the material is determined, the contact resistance depends on the small bump and oxide film on the metal surface. The small bump facilitates obtaining the desired heating range of the contact resistance, but the increased resistance leads to local heating due to the presence of the oxide film and should therefore be removed.