VARIABLE POLARITY PLASMA ARC WELDING OF ALUMINUM ALLOYS

PDF

Authors
  1. Pistor, R.J.
  2. Labbe, G.R.
  3. Tuttle, W.H.
Corporate Authors
Liburdi Engineering Ltd, Dundas ONT (CAN);Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
When compared with gas tungsten arc welding (GTAW), plasma arc welding (PAW) has significant advantages. These advantages include: complete joint penetration, less joint preparation, improved weld quality and soundness, decreased distortion and reduction in the number of weld passes. The welding of aluminum alloys is aggravated by the formation of an oxide layer which has generally a high free energy of formation. Previous attempts to weld aluminum with Direct Current Electrode Positive (DCEP) or Direct Current Electrode Negative (DCEN) were unsuccessful due to severe cutting through the joint, weld metal porosity, electrode degradation, and incomplete fusion. to overcome aluminum's strong tendency to form an oxide an alternating current (AC) power supply is used. The success of the AC power supply is limited due to electrode deterioration, lack of weld pool control, the need for superimposed high frequency and decreased amperage capability of the welding torch. The final solution in plasma arc welding of aluminum alloys is achieved by using a "VARIABLE POLARITY" (DC) power supply. This approach produces cyclic changes of DCEN and DCEP polarities with independent control of current amplitude and duration. This "state-of-the-art" technology allows for proven superior results in all parameters. TRUNCATED
Report Number
DREA-SR-97-002-PAP-18 — CONTAINED IN 98-00986
Date of publication
01 Oct 1997
Number of Pages
10
DSTKIM No
98-01004
CANDIS No
507221
Format(s):
Hardcopy;Document Image stored on Optical Disk

Permanent link

Document 1 of 1

Date modified: