| Abstrakt: |
The paper presents brief retrospective of progress and state-of-the-art of hybrid laser-plasma welding. It is shown that the main objectives of HLPW include not only plasma-arc heating of item metal to increase its absorptivity, but also modification of welding thermal cycle to lower the rate of cooling after welding. This allows lowering the content of brittle structures prone to fracture in service. Moreover, presence of plasma-arc component of the process allows lowering the requirements to quality of fit-up of the butts to be welded, compared to laser welding. Prospects for introduction of HLPW into industry are related to its cost and technological advantages. Cost advantages consist in partial (up to 50 %) replacement of quite expensive laser power by much less expensive arc power, as well as reduction of process power input due to the possibility of filler wire replacement by the respective powder or complete elimination of filler material. Technological advantages consist in reduction of residual thermal deformations, lowering of requirements to preparation of edges to be welded (including the possibility of welding edges with a variable gap), obtaining the ability of cathode cleaning of aluminium alloys directly during welding, increase of penetration depth and process efficiency (several times compared to plasma welding and by approximately 40 % compared to laser welding). Introduction of laser-plasma welding can change the current ideas of technologists about the welding process and those of designers about welded structure design. Industrial application of laser-plasma technology is, primarily, associated with solving the problems of joining titanium and aluminium alloys, as well as stainless steels in the range of thicknesses of 0.3-15 mm. [ABSTRACT FROM AUTHOR] |
