The welding of low-carbon steel in welding repair involves a wide range of coatings. It has low carbon content and low alloying elements, and has good welding performance. It is easy to master by manual arc welding for various joint forms and welding positions, and it is fast and welded. The process and technology are relatively simple and therefore widely used.

1. Welding equipment: AC arc welding machine (BX1-330) can be used, and rotary DC arc welding machine (AX-320) can also be used.

2. The selection of welding rod: according to the material of the welding repair parts, such as (20, Q235), E4303 (J422) welding rod can be used for matching welding. At the same time, according to the thickness and spatial position of the welding repair, the following welding rods of different diameters can be selected (2.5, 3.2, 4.0).

3. The choice of welding current: the choice of manual arc welding welding current is the most important one of the welding process parameters. Therefore, the welding current during the operation of the welder determines the quality of the weld. When the current is too large, the penetration is large, the splash is large, the welding rod is overheated, the coating is easy to fall off, and the forming is poor, and it is easy to bite; when the current is too small, the arc is difficult to arc and the fusion is not good. Therefore, the correct selection of welding current is a key part of ensuring welding quality, which is determined according to the thickness of the workpiece, the spatial position, and the diameter of the welding rod. Generally, the empirical formula for the welding current is in the range of the electrode diameter × 40 to 50. For example, the welding current of the 4 welding rod is preferably 160 to 200 A.

Of course, there are also arc voltage, welding speed, preheating and post-weld heat treatment, but these have little effect on the commonly used steel for welding repair (low carbon steel).