English

The hazards and preventive measures of welding arc blow

I. What is welding arc blow?

Welding arc blow refers to the phenomenon that the arc deviates from the original axis direction of the electrode or electrode during the welding process, which will directly destroy the stability of the arc, affect the weld shape and welding quality, and even cause the welding to fail to proceed normally in severe cases.

II. Why does the welding arc blow? What are the dangers?

There are three factors that cause welding arc blow:

(1) Arc blow caused by excessive eccentricity of the electrode coating:

During arc welding, the melting speed of the electrode coating is slower than the melting speed of the welding core. During the welding process, the electrode coating forms a sleeve, which is beneficial to protecting the arc. When the thickness of the electrode coating is uneven, the melting speed of the thick coating is slower than that of the thin coating, and the length direction of the coating casing will be deflected during the welding process, which will inevitably cause the arc to deflect in the direction of the thin coating.

(2) Arc blow caused by uneven magnetic field intensity in the arc area:

Due to the asymmetric magnetic field force on both sides of the arc axis, the arc is biased in the direction of weak magnetic field intensity. When there is a good conductor (such as rib plate) on one side of the arc zone, the arc will be biased to the conductor side. If the cable connecting the workpiece is connected to the left side of the arc axis, the arc will blow to the right.

(3) The air flow interference around the arc causes the arc to blow:

The arc blows along the direction of the air flow, that is, from the strong air flow to the weak air flow.

The result of arc blowing destroys the stability of the arc, resulting in poor protection of the arc area and serious spatter, which can cause welding defects such as pores and incomplete penetration.

III. What are the measures to prevent arc blow?

Measures to prevent arc blow include:

(1)
Select a welding rod with non-eccentric coating and dry it according to regulations.
(2)
Use short arc operation to enhance the “stiffness” of the arc to offset the impact of arc blow.
(3)
Adjust the welding angle of the welding rod so that the inclination angle of the welding rod is in the opposite direction of the arc blow, and improve the arc blow phenomenon by changing the welding inclination angle.
(4)
When welding the first layer of a butt weld with a gap, a backing plate or filler wire can be added to the back of the gap to prevent arc blow caused by thermal convection. The reverse segmentation method or adding arc starting plates and arc extinguishing plates at both ends of the weld can also be used to improve arc blow caused by thermal convection.
(5)
Use AC power as much as possible in welded steel structures (such as reinforced beam and column structures).
(6)
Make the magnetic field force around the arc evenly distributed as much as possible by changing the position of the cable (ground wire) connecting the weldment.
Post time: Jul-02-2026

Send your message to us: