Overlap laser welding of 5052-H36 aluminum alloy: experimental investigation of process parameters and mechanical designs

Mohamad Idriss,Ahmed Maslouhi,Alain Desrochers,Fatemeh Mirakhorli

doi:10.1007/s00170-022-08783-3

Abstract

In this study, the laser welding process is used to join 1.6-mm-thick AA5052-H36 sheets in an overlap joint configuration. Both pulse and oscillation laser beam welding were investigated for the first laser pass. Oscillation beam laser welding in continuous-wave mode show more stable and sound weld with no porosity defects compare to pulse wave (PW) mode. The adopted welding power, speed, frequency, and defocus are 8 kW, 6.5 m/min, 150 Hz, and + 8 mm, respectively. The obtained stitch welds are defects free (blowholes, micro-cracks, or porosities). A circular oscillation ramp-up/ramp-down PW mode is adopted for a second laser surface re-melting (LSR) pass. The corresponding welding power, speed, frequency, and defocus are 5 kW, 2.5 m/min, 500 Hz, and + 15 mm, respectively. Shear tests are then performed to evaluate the mechanical properties of single lap joints (SLJ) for different stitch weld shapes, 2 gap tolerances (0 and 0.5 mm), as well as with/without LSR pass. The best tests’ reproducibility and highest dissipated energies (~ + 42% when compared to the perpendicular direction) are obtained when the stitch weld direction corresponds to the loading direction. The second LSR pass provides more aesthetic joints with higher shear resistance (~ + 1% to + 3%) due to a decrease in the weld surface underfill and undercut imperfections of the stitch weld. The part-to-part gap leads to higher shear resistance (~ + 20%) owing to 2 main reasons: larger welding surfaces at the joint interface and higher hardness of the fusion zone. These findings are of great value for including laser welding technology in the automotive and surface transportation industries.Graphic abstract

Highlights

Over the past few decades, increasing demand for lightweight structures has led to an increase in the application of aluminum alloys (AA) in automotive industries [1]
The progressing application of laser welding technique for joining AA is mostly due to its unique characteristics such as high-power density that lead to a narrow fusion zone (FZ) and heat-affected zone (HAZ) [7], high penetration depth and production rate, low-stress concentration, and high weld accessibility for complex geometry [8]
We investigate the feasibility of the laser welding process for joining 1.6-mm AA5052-H36 sheets in an overlap configuration

Summary

Introduction

Over the past few decades, increasing demand for lightweight structures has led to an increase in the application of aluminum alloys (AA) in automotive industries [1]. In [5] and [6], an extensive study for joining Al alloys using laser welding was presented. The progressing application of laser welding technique for joining AA is mostly due to its unique characteristics such as high-power density that lead to a narrow fusion zone (FZ) and heat-affected zone (HAZ) [7], high penetration depth and production rate, low-stress concentration, and high weld accessibility for complex geometry [8]. Similar results were obtained by using an Nd:YAG laser welding source for joining magnesium alloy [9]. By choosing the right laser power, speed,

Results

Discussion

Conclusion