Before buying one, make sure your welding current is supported by your welding rods. In most circumstances, a larger welding current, such as 225 amps for 7018, is preferable to 125 amps for 6010. The supported current type (AC or DC) is also something to consider before purchasing a welding rod.

1) Select the appropriate welding current value according to factors such as the type of welding rod. Select the welding current according to the plate thickness and welding rod diameter. The current is proportional to the plate thickness and welding wire diameter. I=(35~55)d, where d is the welding rod diameter. For example, if the welding rod diameter is 4mm, the welding current value is selected between 140-220A.
2) Select the welding current according to the welding position: 140A (overhead weld), 140-160A (vertical butt joint, horizontal butt joint), 180A or more (flat butt joint)
If it is full-position welding (including flat, horizontal, vertical, and overhead positions), the selected welding current value should be the full-power current value, generally the vertical welding current value. When welding horizontal fixed pipes, the full-position welding current is used, and the vertical butt welding current value is generally taken.
3) Select the current value according to the welding layer: generally, a smaller current value is used for the base layer, a larger current value is used for the filling layer, and the current value of the cover layer is relatively reduced. For example, when welding flat joints, multi-layer and multi-pass welding is generally used for beveling. The base layer uses a current of 150A, while the filling layer can use a current value of 180-200A. The cover layer uses a current value reduced by 10-15A to ensure beautiful molding and no welding defects such as undercutting.
4) Select welding current based on production experience: Look at spatter. The welding current generally increases the arc force and the spatter is large; when the welding current is small, the arc force is small, and the slag and molten iron are not easy to distinguish. Look at the weld formation: large welding current is easy to undercut and the residual height is small; small welding current makes the weld narrow and high. Look at the melting condition of the welding rod: large welding current makes the welding rod melt quickly and turn red, and small welding current makes it easy to stick to the arc.

1) Select the appropriate welding current value according to factors such as the type of welding rod. Select the welding current according to the plate thickness and welding rod diameter. The current is proportional to the plate thickness and welding wire diameter. I=(35~55)d, where d is the welding rod diameter. For example, if the welding rod diameter is 4mm, the welding current value is selected between 140-220A.

2) Select the welding current according to the welding position: 140A (overhead weld), 140-160A (vertical butt joint, horizontal butt joint), 180A or more (flat butt joint)
If it is full-position welding (including flat, horizontal, vertical, and overhead positions), the selected welding current value should be the full-power current value, generally the vertical welding current value. When welding horizontal fixed pipes, the full-position welding current is used, and the vertical butt welding current value is generally taken.

3) Select the current value according to the welding layer: generally, a smaller current value is used for the base layer, a larger current value is used for the filling layer, and the current value of the cover layer is relatively reduced. For example, when welding flat joints, multi-layer and multi-pass welding is generally used for beveling. The base layer uses a current of 150A, while the filling layer can use a current value of 180-200A. The cover layer uses a current value reduced by 10-15A to ensure beautiful molding and no welding defects such as undercutting.

4) Select welding current based on production experience: Look at spatter. The welding current generally increases the arc force and the spatter is large; when the welding current is small, the arc force is small, and it is difficult to distinguish between slag and molten iron. Look at the weld formation: large welding current is easy to undercut and the residual height is small; small welding current makes the weld narrow and high. Look at the melting condition of the welding rod: large welding current makes the welding rod melt quickly and turn red, and small welding current makes it easy to stick to the arc.