Industrial application of hybrid laser-arc welding (Review)

Abstract

Welding technology improvement is the prerequisite for progress of industrial production. Development of new structures often requires application of high-efficient welding processes, which ensure minimizing the residual deformations. Unfortunately, capabilities of the traditional arc technologies do not always meet such requirements. Laser welding technologies are not always acceptable, either, in view of the high equipment cost and requirements to preparation of items to be welded. Over the recent years hybrid laser-arc welding technologies, combining the advantages of arc and laser processes, have become ever wider accepted. Therefore, this work is a review of modern tendencies in development of hybrid laser-MIG welding of metals and alloys. It is shown that alongside continuation of research, such tendencies include industrial application (for instance, in different sectors of transportation, chemical, power and food industry) oriented towards partial replacement of laser and arc welding technologies. Examples of such applications are given. Development of new technologies of hybrid welding, focused on joining structures differing by their composition and geometry, as well as designing new production equipment for realization of these technologies is noted. Under the conditions of a new stage in laser equipment development, which began in the last decade, and which is associated with a broad industrial introduction of fibre and disc lasers, the issue of selection of laser or hybrid welding has become the subject of scientific-technical and economic analysis. 37 Ref., 5 Figures. K e y w o r d s : hybrid laser-MIG welding, welding heads, process parameters, mode selection, development history, industrial application Welding technology improvement is a prerequisite for progress of industrial production. Creation of new structures often requires application of high-efficient welding processes, which ensure minimizing the residual deformations. Unfortunately , the possibilities of traditional arc technologies do not always meet such requirements. Laser welding technologies are not always acceptable , either, in view of the high cost of equipment and requirements to preparation of items to be welded. Over the recent years, hybrid laser arc welding technologies, combining the advantages of arc and laser processes, have been ever wider accepted. This study is devoted to tendencies in their development. As was shown by Steen et al. in their works [1, 2], combining laser radiation with electric arc allows development of new welding technologies , offering considerable technological advantages , compared to laser welding (Figure 1) [3]. These advantages include, primarily, deep penetration , low level of residual stresses and lower requirements to fit-up of the edges to be welded. Heating of metal being welded by the electric arc increases the coefficient of laser radiation absorption , that leads to lowering of laser energy losses and allows welding speed to be increased. The same effect is manifested in increase of cross-Figure 1. Schematic of hybrid laser-MIG welding [3]: 1-laser radiation; 2-laser plasma; 3-vapour-gas channel; 4-consumable electrode arc; 5-shielding gas; 6-weld pool