Selection of parameters in nanosecond pulsed wave laser micro-welding

Stainless steel 316L is an austenitic alloy that is widely used in varying industries due to its outstanding corrosion resistance, high strength, and ductility properties. However, the wear and friction resistance properties are low. Laser surface texturing can improve the wear and friction resistance of the material via the functionalisation of the surface. The laser surface texturing efficiency and the texture quality are defined by the material’s surface properties and laser parameters. The surface roughness is an important material property having an effect on laser surface texturing. This paper reports on a study of the material’s surface roughness influence on the texturing of 316L stainless steel with 1064 nm nanosecond pulsed laser. Single pulse shots were employed to avoid the topographic influence of the previous laser shots. The surface shape and the topography of the textures were assessed using optical microscopy and profilometry. It was observed that the textures produced were dimples of U-type and sombrero-like type geometries depending on surface roughness and pulse energy. The overall quality of the texture shape was better for smoother surfaces. The energy fluence necessary to generate textures is lower on surfaces of lower roughness than surfaces with high roughness. The surface at 24 nm of average roughness is the best surface for creating deep textures. The ablation mechanisms associated with high pulse energy, including plasma shielding, are produced at lower pulse energies for the 100 nm roughness, compared with other roughness samples.

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“…The power measurements were taken for 60 s. Maximum pulse energy was estimated with the Eq. 3 [42,43].…”

Section: Laser Equipment and Parametersmentioning

confidence: 99%

Effect of Surface Roughness on the Surface Texturing of 316 l Stainless Steel by Nanosecond Pulsed Laser

Al-Mahdy

Kotadia

Sharp

et al. 2022

Lasers Manuf. Mater. Process.

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“…and modulated pulsed wave mode [29] In CW mode, the process can be specified using power density (q p ), interaction time (t i ) and specific point energy (E SP ), as given by Eqs. (1-3) [26].…”

Section: Fig 1 Differentiation Of Lasers In Terms Of Temporal Outputs In Continuous Wavementioning

confidence: 99%

Comparison of Continuous and Pulsed Wave Lasers in Keyhole Welding of Stainless-Steel to Aluminium

Coroado

Ganguly

Williams

et al. 2021

Preprint

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A continuous wave (CW) and a nanosecond pulsed wave (PW) lasers were used to join 1 mm thick sheets of SS304L (SS) austenitic stainless-steel to AA5251 (Al) aluminium alloy in an overlap joint configuration. The weld shape (penetration depth and width), intermetallic compounds concentration, weld quality (cracking and porosity) and mechanical strength were correlated with the process energy and compared between each laser temporal mode. Successful CW joints were produced with the SS sheet on top of the Al, but the opposite configuration revealed to be impossible for the range of parameters tested. The PW joints were successful with the Al sheet on top of SS, but all the joints cracked at the interface when the opposite configuration was used. The mechanical tests showed that even though it is possible to achieve higher tensile shear load in CW welds due to the larger bonding area, the load per unit of weld length revealed to be almost 5x higher for PW welds at similar applied energy.

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“…Galvanized steel sheets are used in various industrial sectors as zinc coatings provide the former with favourable corrosion resistance in adverse weather conditions. The welding of zinc-coated materials requires complying with special HSE regulations as the joining process may trigger the emission of harmful zinc oxide (zinc melting point being 419.5 °C) [ 26 , 27 , 28 , 29 , 30 , 31 ]. In addition, molten zinc can penetrate steel grain boundaries, ultimately reducing the plasticity of joints.…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Laser Beam Welding of Galvanized Car Body Steel with an Additional Organic Protective Layer

et al. 2023

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This study discusses the effect of laser beam welding parameters on the structure, mechanical properties and corrosion resistance of 1.2 mm thick galvanized sheets made of low-carbon steel DC04 provided with a ZE36/36 GardoprotectOC2BU organic coating. The test laser beam butt welded joints were made without the filler metal, using a variable welding rate, where linear welding energy was restricted within the range of 30 J/mm to 90 J/mm. The joints were subjected to non-destructive tests, destructive tests and corrosion resistance tests. The tests revealed the possibility of making joints meeting the criteria specified in the ISO 15614-11 standard. Regardless of the value of linear welding energy applied in the process, all the joints were characterised by high mechanical and plastic properties. It was noticed that an increase in linear welding energy from 30 J/mm to 90 J/mm was accompanied by the widening of the weld and that of the heat-affected zone (HAZ). In addition, an increase in linear welding energy was accompanied by a decrease in the maximum weld hardness to approximately 250 HV0.2. In the HAZ, hardness was restricted within the range of 190 HV0.2 to 230 HV0.2 and decreased along with increasing linear welding energy. In the static tensile test, regardless of the value of linear welding energy, the test specimen ruptured in the base material. In the bend test, regardless of the value of linear welding energy, a bend angle of 180° was obtained without partial tear or scratches; unit elongation was restricted within the range of 29% to 42%. The electrochemical tests and experiments performed in the salt spray chamber revealed the very high effectiveness of the corrosion protections against aggressive chloride ions.

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Selection of parameters in nanosecond pulsed wave laser micro-welding

Cited by 11 publications

References 31 publications

Effect of Surface Roughness on the Surface Texturing of 316 l Stainless Steel by Nanosecond Pulsed Laser

Effect of Surface Roughness on the Surface Texturing of 316 l Stainless Steel by Nanosecond Pulsed Laser

Comparison of Continuous and Pulsed Wave Lasers in Keyhole Welding of Stainless-Steel to Aluminium

Assessment of the Laser Beam Welding of Galvanized Car Body Steel with an Additional Organic Protective Layer

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