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Laser Surface Treatment of Sintered Stainless Steels for Wear Resistance Enhancement
摘要： In the present study, sintered austenitic stainless steel type 316L was laser surface alloyed with Inconel 625 powder by the fibre optic laser. The Inconel 625 spheroidal powder of grain size 60-150 μm was introduced by the coaxial feeding head directly to the liquid metal, during laser surface alloying. The process parameters were selected to melt and fully dissolve alloying powder into the alloyed surface. As a result of laser alloying, the porosity of sintered stainless steel was eliminated, a uniform distribution of nickel and molybdenum in the entire alloyed zone was obtained. The alloyed surface shows fully austenitic microstructure of 17%Cr, 18%Ni, 3%Mo. The superficial hardness, microhardness and surface wear resistance were significantly improved in respect to an untreated substrate material. The presented technique of laser surface alloying can be easily applied for sintered austenitic stainless steel components where selected component surfaces require an improved surface performance.
关键词： Inconel 625,laser surface alloying (LSA),sintered stainless steels 316L,hardness,wear resistance
更新于2025-09-12 10:27:22
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Characterization of Laser-Welded Ti Alloy and Stainless Steel Joint Using Cu Interlayer
摘要： In this study, Cu was used as an interlayer to restrain the formation of brittle Ti-Fe intermetallics when joining Ti alloy to SS. Microstructures of the joint were analyzed using optical microscopy, scanning electron microscopy and x-ray diffraction. Besides, the tensile strength of the joint was also measured. The melting amount of base materials was controlled by changing thickness of Cu interlayer to control the melting proportion in weld. The melting amount of base materials in weld decreased with the thickness of Cu interlayer. The content of Cu solid solution in weld increased with the thickness of Cu interlayer. Ti-Cu compound layer was formed on the Ti alloy side. The width of the Ti-Cu compound layer increased with the increase in heat input. The tensile strength of joint was largely impacted by Ti-Cu compound layer. The tensile strength of joint ?rst increased and then decreased with the increase in width of the Ti-Cu compound layer.
关键词： mechanical property,microstructure,TC4 Ti alloy,laser welding,SUS301L stainless steel
更新于2025-09-12 10:27:22
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Process Design of Laser Powder Bed Fusion of Stainless Steel Using a Gaussian Process-Based Machine Learning Model
摘要： In this work, a Gaussian process (GP)-based machine learning model is developed to predict the remelted depth of single tracks, as a function of combined laser power and laser scan speed in a laser powder bed fusion process. The GP model is trained by both simulation and experimental data from the literature. The mean absolute prediction error magni?ed by the GP model is only 0.6 lm for a powder bed with layer thickness of 30 lm, suggesting the adequacy of the GP model. Then, the process design maps of two metals, 316L and 17-4 PH stainless steels, are developed using the trained model. The normalized enthalpy criterion of identifying keyhole mode is evaluated for both stainless steels. For 316L, the result suggests that the DH (cid:2) 30 criterion hs should be related to the powder layer thickness. For 17-4 PH, the criterion should be revised to DH hs (cid:2) 25.
关键词： stainless steel,process design,Gaussian process,machine learning,laser powder bed fusion
更新于2025-09-12 10:27:22
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Fiber laser induced self-organizing structures of 316L stainless steel surface
摘要： When the micro-nano groove structure is processed on the surface of 316L stainless steel by a fiber laser, a self-organizing structure with regular distribution appears. After optimizing the processing parameters, the self-organizing structure with excellent quality can be formed in the groove. In order to further research the properties of the self-organizing structure, the large-area self-organizing structures with different spacings are processed. It is found by the characterization that when the spacing is 50 um, the contact angle of the large-area self-organizing structure is increased by 43.1% with respect to the smooth surface, and its wetting property changes from hydrophilicity to hydrophobicity. The component and the phase composition of the self-organizing structure were found to be consistent with the composition of the original material, and it is preliminarily concluded that the self-organizing structure is formed by the splashing flow of molten liquid in the oxidizing molten pool.
关键词： self-organizing structure,fiber laser,contact angle,component,316L stainless steel
更新于2025-09-12 10:27:22
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Laser-assisted micro-milling of austenitic stainless steel X5CrNi18-10
摘要： This paper presents a novel Laser-Assisted Micro-Milling (LAMM) process of austenitic stainless steel X5CrNi18-10. The LAMM process is compared with the conventional micro-milling process. Ultra-short pulsed laser radiation is utilized for the structuring of the workpiece surface prior to the micro-milling process. Different laser structures are produced on the workpiece surface at a constant laser scanning speed with various laser powers and laser line spans. The high performance of the developed process is shown by experimental investigations. The effect of laser structuring on the micro-milling forces and temperature indicated the superior performance of the new LAMM process. Cutting forces and temperature could be reduced by up to 70% and 50%, respectively. The results of conventional micro-milling showed that increasing the cutting speed, at a constant undeformed chip thickness, reduced the micro-milling forces. Increasing the cutting speed from 50 to 250 m/min halved both the trust and normal forces, while it slightly improved the surface roughness. On the other hand, increasing the feed per tooth degraded the surface roughness and increased the cutting forces. Furthermore, in conventional milling the workpiece was subjected to high plastic deformation during the cutting process, while side flow, smeared material, metal debris, and cavities were observed on the workpiece surface.
关键词： Laser-assisted micro-milling,Austenitic stainless steel,Ultra-short pulsed laser,Laser structuring,Micro-milling
更新于2025-09-12 10:27:22
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High-nitrogen steel laser-arc hybrid welding in vibration condition
摘要： Welding porosity and nitrogen content are considered significant factors affecting the mechanical properties of fusion-welding joints of high-nitrogen steel. In this study, a method of applying mechanical vibration in the welding process to reduce weld porosity and increase weld nitrogen content was investigated. The effects of mechanical vibration on porosity, tensile, and impact properties were analysed. The results indicated that the bubble floating speed in the vibrating weld pool is faster than that in the general welding mode. With the increase of mechanical vibration frequency, the porosity of the weld decreased at first and then rose. The tensile strength and impact energy increased first and then decreased, and the fracture surface indicated a ductile fracture.
关键词： nitrogen content,vibration,porosity,austenitic stainless steel,high-nitrogen steel,Laser-arc hybrid welding,microstructure,mechanical properties
更新于2025-09-12 10:27:22
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[Laser Institute of America ICALEO? 2016: 35th International Congress on Applications of Lasers & Electro-Optics - San Diego, California, USA (October 16–20, 2016)] International Congress on Applications of Lasers & Electro-Optics - Controlling the wettability of stainless steel by surface texturing using a high power femtosecond fiber laser
摘要： In this work, stainless steel samples have been textured by a simple and fast one-step laser process. The particularity of this process is the use of an ultrashort pulsed laser technology, combining a high power pulses at high repetition rate. An improved productivity can thus be considered. Successive ablations by IR laser pulses allow to generate dual-scale surface structures. Hierarchical structures, composed of micro-hills on which are superimposed periodic nano-ripples, have been produced at the repetition rate of 50 kHz, by a repeated irradiation of a crossed pattern of parallel lines. In order to increase the process throughput, repetition rates of 100, 250 and 500 kHz have been tested. After an adaptation of the process parameters, topographies with the same dimensions of structures have been created. The presence of these structures modifies the wetting properties of the material. Immediately after laser irradiation the surface becomes hydrophilic; however this wetting state evolves to become superhydrophobic with contact angles higher than 160° and water droplets unable to adhere to the surface. The temporal evolution of the wettability results from the combination of the surface roughness and the chemical composition of this surface. The modeling of the wetting behavior of water droplet, deposited on grooves structures, shows the enhancement of the initial wettability of the surface.
关键词： wettability,superhydrophobic,femtosecond laser,stainless steel,surface texturing
更新于2025-09-12 10:27:22
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Parametric Study of Underwater Laser Welding on 304 Austenite Stainless Steel
摘要： The underwater laser welding assisted by a single-layer gas torch was carried out on the austenite stainless steel based on the underwater laser welding experimental platform. Butt welding experiments under shallow water were performed to investigate the effects of laser power, welding speed and defocusing distance on the underwater laser welding quality and optimized the process parameters. It was found that the ideal underwater laser weld can be obtained with the laser power of 2.0 kW, the welding speed of 2.0 m/min and the defocusing distance of 1 mm, demonstrating the self-developed single-layer gas-assisted drainage device could create working environment similar to onshore laser welding, by analyzing the metallographic structure and mechanical properties of underwater laser weld and in-air laser weld.
关键词： austenite stainless steel.,Underwater welding,laser welding
更新于2025-09-11 14:15:04
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Laser cladding process of Cobalt and Nickel based hard-micron-layers on 316L-stainless-steel-substrate
摘要： In the present study, two different types of coatings such as Cobalt (Co-Cr-W-C) and Nickel (Ni-Cr-B-Si-C) based layers have produced using a high power of Ytterbium-doped yttrium aluminum garnet (Yb:YAG) disk laser on 316L stainless steel substrate. Then the coatings were analyzed to expose their phase characterization, microstructure, and hardness using X-ray diffraction analysis, electron microscopes and microhardness tester. Further, tribo-test has performed through a ball-on-plate machine to analyze the wear properties of coatings. Besides, worn-surfaces of cladding and surface roughness have examined. The results showed that both Cobalt and Nickel based cladding have exhibited a dendrite homogeneous structure with some changes in shape and grain size due to higher cooling rates. XRD results indicate that the mixing of a γ-Co peak with other metastable phases such as Cr7C3 and Cr23C6 were noticed on Cobalt coating and γ-Ni rich matrix was the most dominant peak in Nickel-based coating. Microhardness of the cladding layers has remarkably increased than the substrate. The wear performance of Nickel cladding has increased than Cobalt cladding and substrate sample, which reveals that Nickel-based laser cladding plays a role in wear resistance. The analyzed wear track indicates that adhesion and abrasion were the two major wear mechanisms.
关键词： cladding,316L,alloys,wear,microstructure,nickel,steel,performance,roughness,stainless,cobalt,surface
更新于2025-09-11 14:15:04
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Experimental and Numerical Investigation of Surface Texturing 316L Stainless Steel by Laser Shock Processing
摘要： Surface texturing is considered as a promising method to reduce friction coefficient and improve wear resistance of frictional pairs. In this study, laser peen texturing (LPT) based on laser shock process is proposed to fabricate dimple array on 316L stainless steel. LTP experiments are carried out to investigate the geometrical characteristics of the micro-dimple. It is shown that LPT is capable of fabricating micro-dimples with good repeatability. Numerical simulation based on finite element method is conducted to further study the process of LPT. It is found that the dimple depth obtained from numerical simulation shows a good agreement with that measured from experiments. Moreover, by means of stress analysis, it is shown that residual compressive stress exists in the specimen, which is supposed to be helpful to improve the triboligical performance of frictional pairs.
关键词： friction reduction,wear resistance,316L stainless steel,surface texturing,laser shock processing
更新于2025-09-11 14:15:04