Electric welding oxygen welding

The basic working principle of electric welding is to reduce the voltage and increase the current through the commonly used 220V voltage or 380V industrial electricity. Electric energy generates huge arc heat to melt covered electrode and steel, while covered electrode melting makes the fusion between steel higher. The coating on the outer layer of the electrode and the CO2 gas sprayed by CO2 welding can prevent the metal from oxidation after melting (knock on the powder to see if it can be welded). Of course, this explanation is popular.

Oxygen welding category

Active gas shielded welding (MAG) of 1, Ar+CO2+O2

2.CO2+O2 (carbon dioxide) welding.

describe

The impact toughness of weld is different with different transition coefficients of alloying elements. In MAG welding, the active gas is only 20%, the transition coefficient of alloying elements in the welding wire is high, and the impact toughness of the weld is high. The active gas of CO2 welding is 100%, and the alloying elements manganese and silicon in the welding wire are jointly deoxidized, so the transition coefficient of alloying elements is slightly lower, and the impact toughness of the weld is not as high as that of MAG welding.

Oxygen is a surface active element, which can reduce the surface tension of liquid metal, make the droplet thinner and make the transition better. It can also reduce the influence of hydrogen. Because of its strong oxidation, it does not need to add too much oxygen to prevent the burning of elements and reduce the splashing oxygen. At 1~3%. Up to 4%.

We added some oxygen to the argon arc welding of aluminum. About 4%. After X-ray inspection, there are almost no air holes. But I don't know why it is easy to burn through, and the color is black.