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Multi-Objective Optimization of High Power Diode Laser Surface Hardening Process of AISI 410 by means of RSM and Desirability Approach
摘要： In this research, laser surface hardening of AISI 410 was carried out by a high power diode laser based on Response Surface Method (RSM). Laser power, scanning speed, and focal plane position were evaluated as input process changeable while geometry dimensions of hardened zone (i.e., Depth and width of hardness), maximum hardness, Microhardness deviation (MHD) from base material in depth, and ferrite phase percentage in the microstructure were evaluated as process output Results. The effect of input parameters on the response variations were studied by statistical investigation. Results indicated that by increasing the laser power and decreasing other parameters, higher surface hardness with significant penetration, and least ferrite percentage would be reached by means of the desirability function approach. By using experimental tests, validation of optimized results was performed. In this research in the optimum conditions, the maximum hardness, maximum depth of hardness and minimum ferrite percentage were achieved 670 Vickers, 2.2 mm and 0.45%, respectively.
关键词： Laser Surface Hardening,High Power Diode Laser,Design of Experiments,Laser Materials Processing,Optimization
更新于2025-09-19 17:13:59
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Inverse estimation of heat input in laser surface hardening with a dual-phase-lag model
摘要： This study deals with the application of the conjugate gradient method for estimating the unknown time-dependent heat input in laser surface hardening based on the dual-phase-lag model. Subsequently, inverse variations of temperature at the heated surface can be obtained. Simulated experimental data, needed for the inverse analysis, are generated by adding random errors to the calculated exact temperatures for the boundary and interior of the medium. Two examples are considered to illustrate the accuracy of the proposed method. The influence of the measurement error and the measurement location upon precision of the estimated results is also investigated. Results show that an excellent estimation on the time-dependent laser heat input can be obtained with any arbitrary initial guess for the test cases considered in this study.
关键词： dual-phase-lag,heat input,laser surface hardening,inverse problem
更新于2025-09-19 17:13:59
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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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Development of mathematical models and optimization of the process parameters of laser surface hardened EN25 steel using elitist non-dominated sorting genetic algorithm
摘要： The ultimate goal of all production entities is to select the process parameters that would be of maximum strength, minimum wear and friction. The friction and wear are serious problems in most of the industries which are influenced by the working set of parameters, oxidation characteristics and mechanism involved in formation of wear. The experimental input parameters such as sliding distance, applied load, and temperature are utilized in finding out the optimized solution for achieving the desired output responses such as coefficient of friction, wear rate, and volume loss. The optimization is performed with the help of a novel method, Elitist Non-dominated Sorting Genetic Algorithm (NSGA-II) based on an evolutionary algorithm. The regression equations obtained using Response Surface Methodology (RSM) are used in determining the optimum process parameters. Further, the results achieved through desirability approach in RSM are compared with that of the optimized solution obtained through NSGA-II. The results conclude that proposed evolutionary technique is much effective and faster than the desirability approach.
关键词： Laser surface hardening,wear rate,coefficient of friction,optimization,NSGA-II
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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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