Abstract
Laser welding of dissimilar stainless steels is of interest when mechanical, corrosion, or esthetical requirements impose the use of a high-performance stainless steels, while production-cost requirements prevent using expensive materials in all the parts of a given device. The compromise may lead to the use of the most expensive material in critical areas and the cheapest one in the remaining. Their union can be materialized by laser-pulsed welding. It has intrinsic difficulties derived from the different physical and chemical properties of the steels, and from the need of preserving the protective passive layer. The present work achieves a welded joint with minimum thermal impact by means of laser pulses, capable of preserving the corrosion resistance of the involved stainless steels. The influence of the parameters to define static and dynamic pulses on the material and on the welding regime, keyhole, or heat conduction, is studied. It is used to calculate the overlapping factor of the pulses on the basis of the real dimensions of the melted area. A continuous joint has been built with dynamic pulses. The corrosion resistance of it has been checked showing a similar behavior to the non-heated material. The microstructure of the optimized joint is associated with a reduced HAZ while its mechanical behavior is suitable for its real application.
Highlights
Laser welding is taking a significant progressively position within the world of industrial processes and manufacturing [1]
While the former is applied when high corrosion resistance is needed, the material has to suffer from significant plastic deformation in the forging process, and it is exposed to extreme temperatures; ferritic stainless steels offer generally worse mechanical, thermal, and corrosion properties in exchange for a lower cost [5]
Considering some slight influence derived from the heating of the material during the development of the seam, the penetration of the laser pulse into the austenitic side can be estimated in a range from 30% to 40% of its total thickness
Summary
Laser welding is taking a significant progressively position within the world of industrial processes and manufacturing [1]. While laser welding is a consolidated technology in the automotive industry [3], the cheapening of laser equipment is making this procedure attractive for other fields, as is the case for the home-appliance industry. In this field, the optimized combination of economical materials with others that have better properties in terms of corrosion, resistance, or quality of surface finish, meets an interesting tool in laser-welding technology to achieve successful and profitable industrial implementation. While the former is applied when high corrosion resistance is needed, the material has to suffer from significant plastic deformation in the forging process, and it is exposed to extreme temperatures; ferritic stainless steels offer generally worse mechanical, thermal, and corrosion properties in exchange for a lower cost [5]
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