Arc Blow Is Caused By

Arc blow is the, usually unwanted, deflection of the arc during arc welding.

There are two types of arc blow commonly known in the electrical welding industry: magnetic and thermal.

Magnetic arc blow [edit]

Magnetic arc blow or "arc wander" is the deflection of welding filler material within an electric arc deposit past a buildup of magnetic force surrounding the weld puddle. Magnetic arc accident can occur because of:

Workpiece connection
Joint design
Poor fit-up
Improper settings
Atmospheric conditions

Arc blow tends to occur if the material being welded has residual magnetism at a sure level, particularly when the weld root is being made, and the welding current is directly current (DC positive or negative).

Magnetic arc blow is popularly attributed to a change in the direction of current as it flows into and through the workpiece. Magnetic arc blow is known to begin at field densities as depression equally 10 gauss and becomes astringent at densities of, equal to or greater than, 40 gauss; information technology is directional and can be classified equally frontward or backward moving forth the joint, but can occasionally occur to the sides depending on the orientation of the poles to the workpiece.

Magnetic arc blow is more common in DC welding than in Air-conditioning welding.

Thermal arc blow [edit]

Thermal arc blow is widely attributed to variations in resistance within the base metal created by the weld pool as it is moved across the workpiece. Thermal arc blow can occur considering of:

Improper surface grooming
Improper travel speed

Thermal arc blow is not as severe as magnetic arc blow, but can still exit undesirable defects in the weld deposit.

References [edit]

"Arc blow: Trouble solver". Diverse Technologies.
"Prevent Arc Blow When Welding". Lincoln Electrical.
Moniz, B.J.; Miller, R.T. (2010). Welding Skills. American Technical Publishers. ISBN978-0-8269-2992-one.