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Laser Brazing of Dissimilar Joint of Austenitic Stainless Steel and Pure Copper
摘要： In many industries, there are applications that require the joining of stainless steel and copper components; therefore, the welding of dissimilar stainless steel/copper joints is a common process. For this investigation, the optimal brazing conditions and suitable filler metals for laser brazing of stainless steel/copper lap joints were studied. Tensile shear force increases with increases in the laser spot diameter or in the laser irradiation angle, which is associated with increased bonding width; however, as bonding width approaches 2 mm, tensile shear force reaches a saturated value due to fracturing at the HAZ of the Cu base plate. In order to obtain joints with high tensile shear strength, laser brazing was optimized by using Cu-Si-based filler metal under the following conditions: laser power: 4 kW; spot diameter: 3mm; laser irradiation angle: 80 degrees; irradiation position shift: 0.6 mm; brazing speed: 0.30 m/min; and filler metal feed speed: 0.30 min. Concerning filler metals, it was found that the Ni-Cu type showed relatively large tensile shear force even at high welding speeds in comparison with those of the Cu-Si, Cu, Cu-Ni, Ni-Cu and Ni types, respectively.
关键词： Laser brazing,Copper,Filler metal,Dissimilar material,Stainless steel,Brazing condition
更新于2025-09-16 10:30:52
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Structurally colored stainless steel processed by using femtosecond laser pulses
摘要： Structurally colored stainless steel (SS) surfaces were produced by using femtosecond laser at normal incidence at ambient conditions. The influence of laser polarization on the surface properties was investigated. The surface morphologies, roughness and color of the laser-treated surface were characterized by using environmental scanning electron microscope (ESEM), roughmeter and atomic force microscope (AFM). Results indicated that the circular polarization leads to more random structures than the horizontally linear polarization. Specimen with the highest surface roughness shows the brightest color. Different colors are cyclically exhibited by changing view angles due to different orders of diffraction. This investigation developed the technique of using femtosecond laser in situ preparation of periodic structures on 304 SS, and indicating that laser polarization is an important parameter to control surface structures to achieve different colors.
关键词： polarization,micro/nanostructure,coloration,Femtosecond laser,stainless steel
更新于2025-09-16 10:30:52
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Multi Response Optimization of Nd:YAG Laser Micro Drilling Characteristics of 304 Stainless Steel using Desirability Function Approach
摘要： Laser micro drilling is a non-traditional machining process for producing micro hole of various sizes and different angle in many modern industrial application, such as aerospace gas turbine, automobile industry, electronics field etc. Laser drilling is extremely high speed with high aspect ratio. However, the quality and accuracy of the holes can be excellent, if the optimal process parameter has set. It is difficult to achieve exact size of hole as per suggested by the equipment manufacturer without any consideration. So this paper addressed to investigate influence of process parameter on drilling characteristics of 304 stainless steel of 1.5 mm thickness material using Nd:YAG laser drilling through desirability function optimization technique. The effect of process parameter taken during machining operation is average power, nozzle stand-off, nitrogen gas pressure to obtain requisite hole quality. The output responses are entry circularity, exit circularity and taper angle were considered performance criteria for the experimentation. Analysis of variance (ANOVA) has been performed to find out the significant process parameter during the micro drilling process. It is found that nitrogen gas pressure is highly influencing factor on the overall response characteristics, which is about 54.62% and nozzle standoff is 2nd highest influencing parameter, which is about 27.69%.
关键词： 304 Stainless Steel,Laser Drilling Machine,Optimization,Desirability,ANOVA
更新于2025-09-16 10:30:52
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Characterisation of 17-4PH metallic powder recycling to optimise the performance of the selective laser melting process
摘要： The advantages of Additive Manufacturing (AM) processes are well known. Particularly, those AM techniques which are used to manufacture metallic parts are of great interest to industry due to the good mechanical behaviour of metallic alloys. Despite this, the quality of the manufactured parts is still an important issue due to the wide range of parameters that can affect them. In some powder bed fusion techniques, such as Selective Laser Melting (SLM), not all the initially distributed metallic powder is used in the process. There is an unmolten portion that can be recycled to ensure both the economic and environmental viability of the process. Even though this powder is unmolten, it is thermally affected due to the high temperatures attained during the process. This fact affects the powder properties and, consequently, the properties of the manufactured parts. Therefore, an analysis of the recycling effects of SLM metallic powders is an important issue in order to establish good recycling procedures and to optimise the process performance.
关键词： Additive manufacturing,17-4PH stainless steel,Powder bed fusion,Selective laser melting,Laser beam melting
更新于2025-09-16 10:30:52
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Nd:YAG laser welding of dissimilar metals of titanium alloy to stainless steel without filler metal based on a hybrid connection mechanism
摘要： In this paper, Nd:YAG laser welding of TC4 Titanium (Ti) alloy and SUS301 L stainless steel (SS) dissimilar metal material was carried out without filler metal by laser biasing. The microstructure and fracture mode of the joint were analyzed by scanning electron microscope (SEM), energy dispersive instrument (EDS), and X-ray diffractometer (XRD). The mechanical properties of the joint were evaluated by a tensile test. The results showed that when the peak temperature was 1116?, the liquid phase existed only in the narrower region of the Ti-SS interface, and the eutectic reaction zone formed a reaction layer, which was mainly composed of (cid:2)-Ti solid solution. Ti-Fe intermetallic compound (TiFe, TiFe2) was formed at the Ti alloy-SS interface by heat conduction of the unmelted Ti alloy. The TEM analysis confirmed the presence of the (cid:2)-Ti and TiFe2 phases. The nucleation and growth of the reaction layer depended on the diffusion rate and atomic concentration of Ti and Fe atoms. The growth of the reaction layer could be effectively promoted by increasing the welding heat input, increasing the peak temperature of the Ti-SS interface and prolonging the reaction time. The tensile strength of the joint could be reached 336 MPa and an elongation was 0.13 %. The eutectic reaction method could control the thickness and size of the Ti-Fe intermetallic compound at the interface of the Ti alloy-SS and improve the mechanical properties of the joint.
关键词： Reaction layer,Microstructure,Mechanical property,SUS301L stainless steel,TC4 Ti alloy,Eutectic reaction
更新于2025-09-16 10:30:52
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[Laser Institute of America ICALEO? 2015: 34th International Congress on Laser Materials Processing, Laser Microprocessing and Nanomanufacturing - Atlanta, Georgia, USA (October 18–22, 2015)] International Congress on Applications of Lasers & Electro-Optics - Hot wire laser cladding for repairing martensite precipitation hardening stainless steel
摘要： Martensite precipitation hardening stainless steel (M-PHSS) is widely used as load-bearing parts because of its excellent overall properties. It is economical and flexible to repair the failure parts instead of changing new ones. However, it is difficult to keep the properties of repaired layer as good as the substrate. Multi-pass layers were cladded on the surface of FV520B by hot wire laser cladding. Response surface methodology (RSM) was used to optimize processing parameters and predict formation quality of multi-pass cladding. Microstructure of the as-cladded layer was non-uniform and divided into quenched and tempered region. For the as-cladded layer, tensile strength was almost equivalent to that of the substrate, while ductility and impact toughness deteriorated much. With using laser scanning, microstructure of the clad layers was tempered to fine martensite uniformly. The ductility and toughness of clad layer were improved to be equivalent to those of the substrate, while the tensile strength was a little lower than that of the substrate. By adding TiC nanoparticles as well as laser scanning, the precipitation strengthening effect was improved and the structure was refined in the clad layer. As a result, the strength, ductility and toughness were all improved further. Finally, high quality clad layers were obtained with equivalent or even superior mechanical properties to the substrate, offering a valuable technique to repair M-PHSS.
关键词： Mechanical properties,Microstructure,Hot wire laser cladding,Martensite precipitation hardening stainless steel,Repair
更新于2025-09-16 10:30:52
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Optimization of CO 2 Laser Cutting of Stainless Steel Sheet for Curved Profile
摘要： Laser cutting is one of the most widely used thermal energy based non-contact type advance machining process. In recent years, considerable experimental investigations have been carried out aiming at improving laser cutting process performance. In this work CO2 laser cutting parameters on stainless steel 304 width 2.5 mm thickness were studied. The cut quality achieved minimum kerf width to cut stainless steel sheet depends on appropriate selection process parameters was investigated. The parameters consider to include laser output power, cutting speed, gas pressure. The effect of cutting parameter on the cut quality was further investigated by monitoring top kerf width, and bottom kerf width using box –behnken designing the response surface methodology. And finally optimized best CO2 laser cutting parameters are selected by using genetic algorithm approach.
关键词： Kerf width,Stainless steel 304,CO2 Laser cutting,GA,RSM
更新于2025-09-16 10:30:52
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Effects of Laser Beam Parameters on Bendability and Microstructure of Stainless Steel in Three-Dimensional Laser Forming
摘要： In this study, the e?ects of beam diameter and hatch spacing between the scanning paths on the bendability and microstructural behavior of an AISI 316 stainless-steel sheet in three-dimensional laser forming were investigated. The strain on the heating lines and that between the scanning tracks were numerically investigated to elucidate the e?ects of process parameters. The strain on heating lines and that between scanning tracks were numerically investigated. The increase in hatch spacing caused a larger amount of counter bending to be retained in the una?ected areas between the tracks through a process dominated by a temperature gradient mechanism (TGM), and also caused a lower deformation. The formation of small equiaxed dendrite grains instead of coarse and inhomogeneous austenite grains occurred during the process at a larger beam diameter and smaller hatch spacing, which increased the bendability of the material, owing to the decrease in anisotropy in the microstructure. Moreover, the increase in the grain size of the reheated overlap region of the deformed sample led to a higher bendability. Under these conditions, the microhardness was also increased owing to the grain boundary strengthening e?ect.
关键词： laser forming,track overlap,stainless steel,laser bending,bendability,hatch spacing
更新于2025-09-16 10:30:52
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Influences of Horizontal and Vertical Build Orientations and Post-Fabrication Processes on the Fatigue Behavior of Stainless Steel 316L Produced by Selective Laser Melting
摘要： In this paper, the influences of build orientation and post-fabrication processes, including stress-relief, machining, and shot-peening, on the fatigue behavior of stainless steel (SS) 316L manufactured using selective laser melting (SLM) are studied. It was found that horizontally-built (XY) and machined (M) test pieces, which had not been previously studied in the literature, in both stress-relieved (SR) or non-stress-relieved (NSR) conditions show superior fatigue behavior compared to vertically-built (ZX) and conventionally-manufactured SS 316L. The XY, M, and SR (XY-M-SR) test pieces displayed fatigue behavior similar to the XY-M-NSR test pieces, implying that SR does not have a considerable effect on the fatigue behavior of XY and M test pieces. ZX-M-SR test pieces, due to their considerably lower ductility, exhibited significantly larger scatter and a lower fatigue strength compared to ZX-M-NSR samples. Shot-peening (SP) displayed a positive effect on improving the fatigue behavior of the ZX-NSR test pieces due to a compressive stress of 58 MPa induced on the surface of the test pieces. Fractography of the tensile and fatigue test pieces revealed a deeper understanding of the relationships between the process parameters, microstructure, and mechanical properties for SS 316L produced by laser systems. For example, fish-eye fracture pattern or spherical stair features were not previously observed or explained for cyclically-loaded SLM-printed parts in the literature. This study provides comprehensive insight into the anisotropy of the static and fatigue properties of SLM-printed parts, as well as the pre- and post-fabrication parameters that can be employed to improve the fatigue behavior of steel alloys manufactured using laser systems.
关键词： fracture,fatigue,selective laser melting,defect,stainless steel 316L
更新于2025-09-16 10:30:52
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Study on Effect of Post Processing on Direct Metal LASER Sintered 420 Stainless steel Infiltrated with Bronze
摘要： Additive manufacturing (AM) of metals is increasing its potential applications in the areas of aerospace, automobile, defense and medical with the processing capability from light to heavy metals, but still low density of the finished products which causes discrimination to functional properties and thus reducing AM process real time efficiency. Current research focus on improving the functional properties of 420 stainless steel specimens which are fabricated by Direct Metal LASER Sintering (DMLS) process and infiltrated with bronze for improving the density. Also post processing i.e. annealing, deep cryogenic treatment and tempering was performed. By studying the mechanical properties like tensile strength, hardness, wear of material of specimens in as fabricated and post processed condition it was observed that post processing treatment will favours in enhancing the functional properties. Also results are compared with SEM and optical microscopy images in order to determine microstructural changes.
关键词： deep cryogenic treatment,Infiltration with bronze,Additive manufacturing,420 stainless steel,annealing,tempering
更新于2025-09-16 10:30:52