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Application of high power pulsed nanosecond fibre lasers in processing ultra-thin aluminium foils
摘要： This study is directed at developing a micro-scale laser scoring process and understanding the laser-material interaction in ultra-thin aluminium foils (160 ??m thickness). The research is carried out by the latest generation of nanosecond pulsed ?bre lasers manufactured by SPI Lasers. Presented comparative analysis of 70 W and 120 W laser types gives important insights for laser functionality and can provide recommendations for scalability of the process and quality assurance. High average power lasers were used to meet the requirement of high processing speed in aluminium foils. Scoring in aluminium foils was analysed using the fundamental laser-material interaction parameters that fully determine the way the material responds to the laser energy independent of the laser system. This approach permits transferring the results from the micro-scale laser process between various laser systems. Energy density and laser power density calculated for considered beam spot area at various frequencies were found to be the parameters that determine the scoring ablation depth in the range of 40 ??m–60 ??m. Microscopic examination of the ablation depth and score quality was carried out by an LED illumination 3D microscope. The SEM micrographs indicated minor growth of material debris from the ejected material.
关键词： Aluminium alloy,Scoring,Pulsed wave,Processing,Nanosecond ?bre laser,Ablation
更新于2025-09-23 15:21:01
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A novel method of laser surface hardening treatment inducing different thermal processing condition for Thin-sectioned 100Cr6 steel
摘要： Hardness, microstructure and residual stresses induced on the engineered steel surface have a significant effect on the manufacturing process and the life time of the components. In the present work, these are analysed on laser-treated layer obtained on 100Cr6 bearing steel surface involving different thermal processing conditions. Prior to laser surface hardening treatment, the steel was spheroidized and hardened and tempered with resulting microstructure comprising of globular carbides in the matrix of martensite and retained austenite. A 20-mm wide diode laser beam was employed with a fixed peak laser power in both continuous wave and pulsed wave modes. Additionally, the treatment was carried out with an arrangement to induce fluid contact beneath the workpiece to enhance the heat transfer coefficient. Results indicated maximum improvement in hardness (1050–1100 HV) and compressive residual stress (?630 ± 20 MPa) with retention of core properties on treated surface processed with pulsed-wave mode under fluid contact owing to formation of refined microstructure constituting refined globular carbides (alloy nano-carbides) and retained austenite in martensite matrix. The extent of increase in compressive residual stress and treated layer microhardness was found to depend on the extent of martensite refinement and alloy nano-carbides dispersed in the matrix. Sliding wear tests conducted in both unlubricated and lubricated conditions indicated gradual improvement in wear resistance of the treated surface with increase in cooling rate governed by the thermal processing condition employed with conventionally hardened and tempered one being lowest and laser processed with pulsed wave mode under fluid contact being highest. Apparently, the laser treated surface processed with pulsed-wave mode under fluid contact exhibited reduction in friction coefficient with retention of core properties as compared to untreated counterpart.
关键词： Pulsed-wave,Spheroidized carbides,Laser surface hardening,100Cr6 bearing steel,Residual stress,Continuous-wave
更新于2025-09-16 10:30:52
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Diode Laser Surface Treatment of Bearing Steel for Improved Sliding Wear Performance
摘要： The high carbon Cr-bearing SAE 52100 steel grade in hardened and tempered condition is widely applications due to various technological advantages like high hardness, strength and good formability coupled with low cost. However, many-a-times, excessive wear along with applications. Engineering the surface of prior-hardened bearing steel by laser surface hardening to further enhance surface hardness without affecting the bulk can be gainfully utilized for tailoring used for the production of bearings in the automotive industry, the machinery industry, the production of wind turbine and the construction industry. 52100 steel is extensively used for these noise/vibration causes premature failure and/or necessitate early replacement of bearings. Furthermore, contact fatigue and bulk toughness are observed to be inadequate in heavy duty/load indicated enhanced microstructural refinement with partially dissolved carbide globules in PW mode as compared to that processed under Continuous-wave (CW) mode. 25-30% higher peak hardness could be achieved in PW mode with retention in core hardness as compared to that of CW counterpart. Sliding wear testing results showed five-fold and three-fold improvements in un- In the present work, the effect of pulsed-wave (PW) mode of hardening on surface hardening of 52100 bearing steel with prior through-hardened condition is investigated and case depth, hardness, microstructure analysis and tribological properties are discussed in detail. Results lubricated and lubricated conditions in laser processed layer as compared to that of untreated one. On the whole, the PW mode of processing showed vast improvement in hardness and sliding wear tribological properties to improve life. resistance.
关键词： Spheroidized carbides,Martensite,Laser surface hardening,Bearing Steel,Pulsed-wave,Continuous-wave
更新于2025-09-11 14:15:04