1. Check the equipment
① Before welding the welding nut, connect the water, gas and circuit of the welding machine, and turn on the power supply of the control box. The operator checks whether the water, gas and electric pipelines are abnormal. The equipment personnel check the network control parameters (network voltage: 360-420V, air pressure: not less than 0.4MPa, whether the cooling water circulation is smooth, the flow is sufficient, and the welding machine has no air leakage, water leakage, or electricity leakage.)
②Check the projection welding machine, and it is required that the electrodes are coaxial and rise and fall smoothly, the pressure adjustment is quick, the program control is normal, and the transformer series knife is in good contact.
2. Welding process test piece
Before each shift of production, make a process test piece, check the quality of the projection welding of the test piece and record it according to the requirements (attached form), and select the nut/bolt of the same specification and brand, and the test piece of the same thickness and material for the test.
3. Inspection method of projection welding nut test piece
Visual inspection: No thread damage, cracks are required, slight splashing and a small amount of metal extrusion are allowed, but it does not affect the screwing of the bolts. Bolt trial installation method: select the bolt that matches the projection welding nut. It is required that no tools can be borrowed. If the bolt can be smoothly screwed into the nut hole by hand, it is qualified; otherwise, the bolt cannot be screwed in or it is difficult to screw in, it is not. qualified.
