Pre-welding of energy storage spot welder and assembly of weldment

Energy storage spot welding machines, also known as capacitive energy storage spot welding machines, energy storage machines, etc., utilize industrial-frequency alternating currents to charge the capacitors after being rectified by rectifiers, and the stored electrical energy is then converted into low-voltage voltages by the welding transformer discharge. The energy is concentrated in a stable pulse current, and the metal is welded by generating resistance heat through the contact point of the workpiece to be welded. Low carbon steel has good weldability. The process parameters of low carbon steel can be changed within a wide range, and good spot welding strength can be obtained with either strong or weak specifications. The following is an introduction to the preparation of spot welding of low energy carbon steel for energy storage spot welders and the assembly of weldments.

1. Preparation before welding

The surface of the weldment before welding should be carefully cleaned to reduce the effect of contact resistance on spot welding quality. When cold-strip steel spot welding, because the cold-rolled steel plate does not have oxide skin, generally do not need special degree, but if the parts during the drawing process have drawing oil or the surface is not clean and the surface quality requirements of the parts are relatively high, then It should be cleaned before welding. In addition, when the surface is rusted or dirty, it should also be cleaned. Otherwise, poor contact may cause quality problems such as burning or welding.

2. Weldment assembly

Welding quality is not only related to the welding method used and the specification parameters, but also has a lot to do with the machining accuracy and assembly accuracy of the parts. If the precision of the part is not high or unstable, the assembly clearance will be too large and burn-through will occur during welding. When spot welding thin sheet structural parts, the assembly gap should not exceed 0.5 to 1.0 mm. In the case of spot welding of heavy plate joints or welds with high rigidity, the assembly clearance is even smaller, preferably not exceeding 0.1 to 0.2 mm. If the part gap is too large, an effective method should be adopted. After the workpiece is contacted and then welded, it can prevent welding or bad welding.