Correct method of welding aluminum by gas shielded welding

Pre-welding preparation, gas and welder selection, welding technology and post-welding treatment.

1. Preparation before welding: completely eliminate the defects, prepare the groove according to the requirements of the workpiece, drill crack stop holes at both ends of the crack, and pad the back with asbestos cloth. The welding wire should be homogeneous or universal, and the flux should be suitable. Choose a suitable medium-sized welding gun.

2. Selection of gas and welding machine: When welding aluminum by gas shielded welding, use a double-pulse gas shielded welding machine. According to the material grade of the workpiece to be welded, select the appropriate welding wire. The gas flow rate should be controlled between15 and 20l/min to ensure the stability of the welding process.

3. Welding process: At the beginning of welding, the preheating temperature is controlled at 250-300℃. Neutral flame is used for preheating and becomes micro-magnetized flame after melting. During the welding process, the tilt angle of the welding nozzle should be kept at 25° ~ 30o. When the weldment melts at the heating place, the welding torch should be lifted and the deep flux welding wire should be sent. When the end of the welding wire melts, the droplets immediately fall into the molten pool. During welding, impurities such as oxide film on the surface of molten pool should be picked up with welding wire at any time.

4. Post-welding treatment: after welding, slow cooling measures should be taken, and annealing treatment at 300℃~ 350℃ can also be carried out to reduce welding stress. After all weldments are cooled, clean the welding slag and flux near the weld with hot water and wire brush. Wash the weldment in flowing hot water for 5 to 10 minutes, then rinse with cold water for 5 minutes, and dry or air dry the weldment.