Ultrasonic-assisted laser welding on AISI 321 stainless steel

A Novel Method of Supporting the Laser Welding Process with Mechanical Acoustic Vibrations

“…The presented results show that the acoustic vibrations input can affect both the geometry of the weld and its face's microstructure. The scale of these changes is not comparable with effects reached in other methods that directly introduce vibrations [1,2,5,10,18,25], but they give the opportunity to reach constant conditions in the welding place using contactless supplying vibration, as in [16,25].…”

“…It is also known that the effective transfer of vibration energy is not easy and depends on the rigidity of the attachment of the vibration system to the welded object. In this case, however, it would be difficult to expect a homogeneous distribution of energy, as shown by the laser vibrometer used for measurements [1]. As could be expected, the energy value (amplitude) strongly depended on the vibration phase in the object [2,18] and the obtained results were conditioned by the occurrence of an arrow or vibration node.…”

“…A careful observer of the literature on the subject will notice that the majority of research in which the authors used mechanical vibrations focuses on the effects obtained, which undoubtedly leads in many cases to the fragmentation of grains [11], changing their shape into more equiaxial forms [12,13], improving mechanical properties such as strength, impact strength or hardness [14][15][16]. Few of these studies attached significant importance to technical problems associated with the effective introduction of vibrations and their form [2,17], and even more so with other parameters such as frequency, amplitude or phase [1,2,12,18].…”

“…Some researchers, such as [1], investigated ultrasonic-assisted laser welding on stainless steel, which was carried out to find out the effect of ultrasonic energy input on the microstructure and the strength of the weld metal. It is well known that the energy of ultrasonic vibrations depends mainly on the amplitude.…”

“…As could be expected, the energy value (amplitude) strongly depended on the vibration phase in the object [2,18] and the obtained results were conditioned by the occurrence of an arrow or vibration node. Therefore, the use of such methods of introducing vibrations whose energy varies with the distance of the source of vibrations from the liquid metal pool does not guarantee repeatable conditions of the technological process [1,2,5,10,12,18].…”