Chapter 7
Keyhole and Weld Pool Dynamics
in Dual-Beam Laser Welding
Abstract This chapter introduces the time-dependent keyhole and weld pool
dynamics in dual beam laser welding. Mathematical model of self-consistent keyhole
and weld pool dynamics in dual beam welding is presented. The coupled keyhole and
weld pool dynamics in dual beam welding are discussed by numerical simulations.
The stabilization mechanisms of a dual beam mode laser arrangement in welding
process are given.
7.1 Introduction
The laser welding features small beam spot diameter, high thermal efficiency and
small thermal input of the welding line, thus the deformation and residual stress of
laser welding are very small. Meanwhile, the thermal influence zone of welding is
narrow and the metal grain coarsening tendency of the weld joint is small, endowing
laser welding typical application advantages. Due to the small beam spot diameter,
high precision is demanded for weldment with single beam laser welding. At present,
for some sheet metal forming thin-wall structural components, it is difficult to ensure
the forming precision as there is a large gap of weldment and certain misalignment,
thus it is often difficult to achieve the assembly precision required by ordinary single
beam laser welding technology. This posed certain challenges for the application of
laser welding technology on the thin-wall structural component. In order to break
through the limitation of single beam laser welding, the dual beam laser welding technology is applied to the welding of thin-wall components. It has become an important
technical approach to realize the optimization and high adaptability welding of the
thin-wall structural component.
Dual beam laser welding separates the same laser into two separate laser beams by
an optical method, or uses a combination of two different types of laser for welding.
By changing the energy ratio, beam spacing and arrangement mode of two laser
beams, the adaptability of laser welding to assembly accuracy can be improved, the
welding temperature field and flow field can be adjusted flexibly, and the evolution
behavior of keyhole and flow form of weld pool can be changed, improving the
stability of the welding process. Therefore, dual beam laser welding is featured with
© China Aviation Publishing & Media Co., Ltd. 2021
S. Gong et al., Weld Pool Dynamics in Deep Penetration Laser Welding,
https://doi.org/10.1007/978-981-16-0788-2_7
183
Keyhole and Weld Pool Dynamics
in Dual-Beam Laser Welding
Abstract This chapter introduces the time-dependent keyhole and weld pool
dynamics in dual beam laser welding. Mathematical model of self-consistent keyhole
and weld pool dynamics in dual beam welding is presented. The coupled keyhole and
weld pool dynamics in dual beam welding are discussed by numerical simulations.
The stabilization mechanisms of a dual beam mode laser arrangement in welding
process are given.
7.1 Introduction
The laser welding features small beam spot diameter, high thermal efficiency and
small thermal input of the welding line, thus the deformation and residual stress of
laser welding are very small. Meanwhile, the thermal influence zone of welding is
narrow and the metal grain coarsening tendency of the weld joint is small, endowing
laser welding typical application advantages. Due to the small beam spot diameter,
high precision is demanded for weldment with single beam laser welding. At present,
for some sheet metal forming thin-wall structural components, it is difficult to ensure
the forming precision as there is a large gap of weldment and certain misalignment,
thus it is often difficult to achieve the assembly precision required by ordinary single
beam laser welding technology. This posed certain challenges for the application of
laser welding technology on the thin-wall structural component. In order to break
through the limitation of single beam laser welding, the dual beam laser welding technology is applied to the welding of thin-wall components. It has become an important
technical approach to realize the optimization and high adaptability welding of the
thin-wall structural component.
Dual beam laser welding separates the same laser into two separate laser beams by
an optical method, or uses a combination of two different types of laser for welding.
By changing the energy ratio, beam spacing and arrangement mode of two laser
beams, the adaptability of laser welding to assembly accuracy can be improved, the
welding temperature field and flow field can be adjusted flexibly, and the evolution
behavior of keyhole and flow form of weld pool can be changed, improving the
stability of the welding process. Therefore, dual beam laser welding is featured with
© China Aviation Publishing & Media Co., Ltd. 2021
S. Gong et al., Weld Pool Dynamics in Deep Penetration Laser Welding,
https://doi.org/10.1007/978-981-16-0788-2_7
183