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Influence of Beam Power and Traverse Speed in Fibre Laser welding of Dual phase steel (590) on Depth of weld zone penetration, Microstructure and Hardness
摘要： The influence of heat input on microstructure, microhardness, and mechanical properties of welded structures of DP 590 (Commercially known as DP 600 grade) grade steel of 1.6 mm thickness sheet has been investigated. The investigation was carried out by using Nd: YAG fibre laser source at a beam power of 1.5 kW and 3.0 kW at a traverse speed of 2 m/min, 4 m/min, and 6 m/min in bead on plate weld configuration. Except at lower beam power and lower traverse speed, at all other combinations of beam power and traverse speed a complete weld penetration has been observed. The weld zone microstructures have been transformed into predominantly martensitic phase due to rapid solidification. The width of the Heat Affected Zone and Weld Zone decreased as the heat input decreased. Hardness values of weld zone has increased to 350 -380 HV from 180-200 HV due to formation of martensite.
关键词： Dual Phase Steel,microhardness,Laser welding,martensite,heat affected zone
更新于2025-09-12 10:27:22
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Effect of substrate material on the molten pool characteristics in selective laser melting of thin wall parts
摘要： Substrate plays an important role in selective laser melting (SLM). In general, the same material substrate is utilized as the powder for SLM. However, there are considerable kinds of aluminum alloy and their physical properties are different. In this work, the effect of three aluminum substrates AlSi10Mg, 6061, and 7050 on the molten pool characteristics was investigated for SLMed AlSi10Mg thin wall parts by experimental and numerical analysis. The thermal behaviors, molten pool characteristics, microstructure, silicon distribution, and microhardness were studied as the deposited layers increase. Results show that these features of the three substrates are different at the first several layers of the thin wall parts then become the same after definite layers. Our results clarify the influence of the substrate materials on the SLM of aluminum thin wall parts, which has important theoretical significance and engineering application.
关键词： Element distribution,Thermal behaviors,Microhardness,Molten pool dimensions,Microstructure,Substrate material
更新于2025-09-12 10:27:22
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An experimental investigation of the effects of diode laser surface hardening of AISI 410 stainless steel and comparison with furnace hardening heat treatment
摘要： This study investigated the ability of the continuous wave diode laser surface hardening of AISI 410 martensitic stainless steel with a maximum power of 1600 W. Variable process parameters scanning speed (4–7 mm/s), laser power (1200–1600 W) and stand-off distance (65–75 mm) were considered in this study. Microhardness, the geometry of hardened layer (depth and width), microhardness deviation from the base metal microhardness (MHD), microstructure analysis of the laser-hardened zone through optical microscopy and field emission scanning electron microscopy and percentage of the ferrite phase in AISI 410 microstructure by using Clemex software were considered as process output responses. Results confirmed that by increasing the laser power and reducing the scanning speed, the surface hardness and the depth of hardness increase. It is also revealed the width of the hardened area increases by enhancing stand-off distance and reducing the laser power. Maximum hardness of 630 HV0.3 with 2.2 mm depth is obtained. Also, the furnace hardening heat treatment is compared with the laser hardening process. Microstructure, microhardness, and impact tests of the two processes are compared. Results showed that the hardness of the diode laser is 1.4 times the hardness of the furnace hardening heat treatment.
关键词： Microhardness deviation,Microhardness,AISI 410 martensitic stainless steel,Laser surface hardening,Diode laser
更新于2025-09-11 14:15:04
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Direct Metal Laser Sintering of Maraging Steel: Effect of Building Orientation on Surface Roughness and Microhardness
摘要： Direct Metal Laser Sintering (DMLS) is a powder bed fusion based Additive Manufacturing (AM) process in which a part is fabricated using layer by layer deposition. In this work, 18% Ni Maraging steel 300 was fabricated using DMLS to examine the variations in surface finish and microhardness using three building orientations i.e. 0?, 45? and 90?. Surface roughness was found to decrease after 20 mm for 45? and 90?. Correspondingly, microhardness was found to decrease in the building direction. Understanding the effect of building orientation on the surface finish and hardness will allow the producer to fabricate superior quality AM parts with desired properties.
关键词： Direct Metal Laser Sintering,Microhardness,Additive Manufacturing,Surface finish,Maraging Steel
更新于2025-09-11 14:15:04
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Laser-thermal Hardening of the Tools Set for Cold-forming Fasteners
摘要： At present the problem of increasing the wear resistance of an impact stamp tool used in the fasteners production by methods of cold forming is very acute problem. The article analyzes the possibility of laser heat hardening to improve the wear resistance of the used tool set.
关键词： production tools,laser heat hardening,fasteners,tool steels,microstructure,microhardness
更新于2025-09-11 14:15:04
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Effect of Centrifugal Shot Peening on the Surface Properties of Laser-Cut C45 Steel Parts
摘要： This article presents the results of experimental studies of the impact of centrifugal shot peening parameters on the roughness, microstructure, and microhardness of the surface layer of laser-cut C45 steel parts. Residual stress distributions and the presence of iron oxides on the surface of these elements were also examined. Centrifugal shot peening tests were performed on an FV-580a vertical machining center while using a specially designed peening head. The parameters that were varied during centrifugal shot peening included tangential speed of the tool vg and feed rate vf. The use of centrifugal shot peening for finish machining of laser-cut C45 steel parts allowed for obtaining a four-fold reduction in the surface roughness parameters Ra and Rz. As a result of shot peening, the geometrical structure of the surface of the steel parts was modified and it acquired new beneficial features, such as large values of the rounding radii of the micropeaks and high material ratios (Rmrmax = 92%). At the same time, the surface layer was hardened (microhardness increased by 16%) and a compressive residual stress layer was produced on the surface of the workpieces. Additionally, as the shot impacted the processed surface, combustion products were “blasted” or “sheared” off it. Shot peening using the proposed technique can be successfully performed while using CNC machines.
关键词： laser cutting,residual stress,microhardness,centrifugal shot peening,microstructure,surface roughness
更新于2025-09-11 14:15:04
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Growth, Optical, Thermal, Mechanical, Laser Damage Threshold and Electrical Polarizability of Cadmium Chloride Doped l-Alanine (LACC) Single Crystal for Optoelectronic Applications
摘要： L-Alanine doped with cadmium chloride crystal was grown by slow evaporation technique in an optimum condition using de-ionized water as solvent. Single crystal x-ray diffraction analysis was carried out to con?rm the unit cell parameters and cell volume. The presence of amine vibrations and carboxylic acid vibrations af?rm the presence of L-alanine in grown material by Fourier transform infrared (FT-IR) analysis. The ultraviolet visible near-infrared region (UV–Vis-NIR) spectrum revealed that the grown crystal has a lower cut-off wavelength at 246 nm and has high transmission in the entire visible region. Further, energy gap and the refractive index of the crystal were also calculated. Thermo-gravimetric (TG) and differential thermal analysis (DTA) were carried out, and it is estimated that the material is thermally stable up to 233°C and the melting point of the crystal was found to be 298°C. The mechanical strength of the material is estimated for various loads using Vicker’s microhardness and it reveals that material belongs to a soft material category. The electrical polarizability was calculated using known values such as valence electron, molecular weight, energy gap and density of the material. Z-scan technique for nonlinear studies was carried out on a LACC crystal to determine the third order nonlinear absorption (b), nonlinear refractive index (n2) and third order nonlinear susceptibility (v(3)) using continuous wave Nd: YAG laser of 532 nm. Grown crystal shows that the material is very much suitable for second harmonic generation for frequency conversion applications.
关键词： electrical polarizability,LDT,Z-scan technique,X-ray diffraction,FT-IR,microhardness,TG-DTA
更新于2025-09-11 14:15:04
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Nd: YAG Pulsed Laser Dissimilar Welding of UNS S32750 Duplex with 316L Austenitic Stainless Steel
摘要： Duplex stainless steels (DSSs), a particular category of stainless steels, are employed in all kinds of industrial applications where excellent corrosion resistance and high strength are necessary. These good properties are provided by their biphasic microstructure, consisting of ferrite and austenite in almost equal volume fractions of phases. In the present work, Nd: YAG pulsed laser dissimilar welding of UNS S32750 super duplex stainless steel (SDSS) with 316L austenitic stainless steel (ASS), with di?erent heat inputs, was investigated. The results showed that the fusion zone microstructure observed consisted of a ferrite matrix with grain boundary austenite (GBA), Widmanst?tten austenite (WA) and intragranular austenite (IA), with the same proportion of ferrite and austenite phases. Changes in the heat input (between 45, 90 and 120 J/mm) did not signi?cantly a?ect the ferrite/austenite phase balance and the microhardness in the fusion zone.
关键词： Nd: YAG,microstructure,austenitic steel,microhardness,laser welding,dissimilar material,duplex steel
更新于2025-09-11 14:15:04
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Investigations on synthesis, growth and physicochemical properties of semi-organic nonlinear optical crystal: l-arginine sodium nitrate
摘要： Single crystals of l-arginine sodium nitrate semiorganic nonlinear optical crystal were grown by slow evaporation process at room temperature. The single crystal X-ray diffraction study confirms that the unit cell parameters of the grown l-arginine sodium nitrate crystal. Fourier transform infrared spectrum analysis was used to identify the functional groups of the grown crystal. The thermal stability of the l-arginine sodium nitrate was determined using thermogravimetric analysis and differential thermal analysis. The linear optical property of LARSN crystal has been studied using Ultraviolet–visible spectroscopy studies in the wavelength range 200–800 nm. The relative second harmonic efficiency of the l-arginine sodium nitrate compound is found to be 0.49 times that of Potassium Di-hydrogen phosphate. The mechanical property of the grown crystals was determined by Vicker’s micro hardness test and it proved the hard nature of the grown crystal. Dielectric study reveals that both dielectric constant and dielectric loss decreases with increase in frequency.
关键词： thermal analysis,l-arginine sodium nitrate,slow evaporation process,FTIR,nonlinear optical crystal,microhardness,dielectric properties,X-ray diffraction,SHG efficiency,UV–Vis spectroscopy
更新于2025-09-10 09:29:36
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Comparison of theoretical and experimental microhardness of tetrahedral binary Zn1-xErxO semiconductor polycrystalline nanoparticles
摘要： polycrystalline nanoparticles with various compositions were prepared using sol–gel techniques, for which zinc acetate dihydrate and erbium 2–4 pentanedionate are used as precursors. Nanoparticles were pressed under a pressure of tons for min into disk-shaped compacts with 2 mm thicknesses and 10 mm diameters. The pressed samples were annealed at 400 °C for min. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Vickers microhardness analyses of the produced Er-doped bulk nanomaterials were performed. Specifically, in this study we focused on the analysis of their mechanical properties. Undoped and Er-doped bulk samples were investigated according to Meyer's law; the proportional sample resistance (PSR), elastic/plastic deformation (EPD), and indentation-induced cracking (IIC) models; and the Hays–Kendal (HK) approach. As a result, the IIC model was more suitable to determine the micromechanical properties and the reverse indentation size effect (RISE) behavior of Er-doped semiconductors.
关键词： Vickers microhardness,Sol–gel,IIC model,RISE,ZnO,Er doping
更新于2025-09-10 09:29:36