TWO MINUTES TO UNDERSTAND PLASMA ARC WELDING
TECHNOLOGICAL FEATURES OF PLASMA ARC WELDING
1) PLASMA ARC welding has high penetration, high welding speed, high temperature, and concentrated energy density.
2) Good resistance to arc length fluctuation and good appearance after welding.
3) The stability of the plasma arc is good, can weld ultra-thin welding part.
4) It can reduce the burning loss of tungsten electrode and prevent the welding seam from clipping tungsten.
ARC WELDING PROCESS
(1) Joint type
Typically, PLASMA ARC welding joints are type I butt joints, single-sided V and double-sided v Groove Butt joints, and single-sided U Groove Butt joints.
(2) Selection of welding parameters
1) NOZZLE APERTURE
In the welding process, when the thickness of the welding piece increases, the welding current should also increase, but can not exceed the maximum allowable current of the nozzle.
2) Welding Current
According to the material and thickness of the weldment, the welding current should be determined firstly, but if the current
is too low, it may make the weldment unable to be penetrated and the welding speed is slow; if the current is too high, it
may cause the weldment to wear out, and even may cause double arc phenomenon.
3) Type and flow of IONIC GAS
Currently, the most widely used is argon, which is suitable for all metals. Some other gases may also be added as appropriate to improve the efficiency and quality of the joint. With the increase of ion gas flow rate, the IMPULSE AND PENETRATION FORCE
OF PLASMA ARC increase.
4) Speed of Welding
The welding speed directly affects the heat input of the weld, so the welding speed depends on the welding current and ion gas flow rate.
5) NOZZLE HEIGHT
Curie is the nozzle height from the nozzle end face to the WELD surface. General nozzle height should be maintained 3 ~ 8 mm is more appropriate.
6) ARC STARTING AND ARC STOPPING
Plate thickness is less than 3mm, can start arc on the workpiece. More than 3mm need to add arc ignition plate and arc-
closing plate.