Arc blow
Encyclopedia
Arc blow is the, usually unwanted, deflection of the arc during arc welding
.
There are two types of arc blow commonly known in the electric welding industry: magnetic and thermal.
. Magnetic arc blow can occur because of:
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 low as 10 gauss
and becomes severe at densities of, equal to or greater than, 40 gauss; it is directional and can be classified as forward or backward moving along 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 AC welding.
as it is moved across the workpiece. Thermal arc blow can occur because of:
Thermal arc blow is not as severe as magnetic arc blow, but can still leave undesirable defects in the weld deposit.
Arc welding
Arc welding is a type of welding that uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. They can use either direct or alternating current, and consumable or non-consumable electrodes...
.
There are two types of arc blow commonly known in the electric welding industry: magnetic and thermal.
Magnetic arc blow
Magnetic arc blow or "arc wander" is the deflection of welding filler material within an electric arc deposit by a build up of magnetic force surrounding the weld poolWeld pool
thumb|Weld pool diagramWeld pool commonly refers to the dime-sized workable portion of a weld where the base metal has reached its melting point and is ready to be infused with filler material. The weld pool is central to the success of the welding process...
. Magnetic arc blow can occur because of:
- Workpiece connection
- Joint design
- Poor fit-up
- Improper settings
- Atmospheric conditions
Magnetic arc blow is popularly attributed to a change in the direction of current
Electric current
Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
as it flows into and through the workpiece. Magnetic arc blow is known to begin at field densities as low as 10 gauss
Gauss (unit)
The gauss, abbreviated as G, is the cgs unit of measurement of a magnetic field B , named after the German mathematician and physicist Carl Friedrich Gauss. One gauss is defined as one maxwell per square centimeter; it equals 1 tesla...
and becomes severe at densities of, equal to or greater than, 40 gauss; it is directional and can be classified as forward or backward moving along 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 AC welding.
Thermal arc blow
Thermal arc blow is widely attributed to variations in resistance within the base metal created by the weld poolWeld pool
thumb|Weld pool diagramWeld pool commonly refers to the dime-sized workable portion of a weld where the base metal has reached its melting point and is ready to be infused with filler material. The weld pool is central to the success of the welding process...
as it is moved across the workpiece. Thermal arc blow can occur because of:
- Improper surface preparation
- Improper travel speed
Thermal arc blow is not as severe as magnetic arc blow, but can still leave undesirable defects in the weld deposit.