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Numerical simulation of temperature distribution and experimentation in laser beam welding of SS317L alloy
摘要： In the present study stainless steel 317L grade was chosen for joining using 400w Nd-YAG laser beam welding process. Tensile strength and temperature distribution are considered as output responses while Welding current, Frequency, Pulse width are taken as process parameters. A butt configuration of 5 mm thick plate of austenitic steel alloy and K-type digital thermocouple was used to observe the temperature experimentally. The welded plates are cut using Electro-discharge machining to prepare Tensile test specimens according to ASTME21 standard. The specimens are tested to get stress-strain graphs and ultimate tensile strengths for all the 9 cases (as per L9 Orthogonal array). Additionally, a 2D transient thermal-structural numerical simulation model was developed to simulate the complete laser welding process. The effect of each parameter has been studied experimentally and numerically. Analysis of variance (ANOVA) has been used for finding out the contribution of each input factor on the output response with the help of MINITAB software. The optimised values of process parameters are utilised to get the thermal profiles and heat-affected zone using finite element simulations. The finite element calculation of process was carried out by a parametric design language APDL available in the ANSYS finite element code. The temperature values obtained using finite element simulation and experiments are matching reasonably good with an error of 12% hence the developed simulated model can be used to study related parameters.
关键词： Tensile strength,Laser beam welding,Optimization,Simulation,FEM,Nd-YAG laser
更新于2025-09-19 17:13:59
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Microstructural characterization and tensile behavior of Nd:YAG laser beam welded thin high strength low alloy steel sheets
摘要： Laser beam welding (LBW) has many advantages to join high strength low alloy (HSLA) steels compared with conventional fusion welding processes. The present work is focused on joining HSLA plates of 2 mm thickness efficiently through the application of Nd:YAG laser source. Only one process variable i.e. the welding speed was operated between 70 mm/s to 120 mm/s while the rest of the variables were maintained constant. The microstructure evolution of the fusion zone was recorded through optical, scanning and transmission electron microscopy. The fusion zone was observed to be wider but no major defects were present. Fusion zone experienced a change in morphology of ferrite and pearlite depending upon the rate of cooling and exposure time. Fusion zone showcased various ferrites such as acicular ferrite, widmanstatten ferrite, and grain boundary ferrite. Advancement in the welding speed helped in the formation of acicular ferrite. EBSD results presented a descending tendency of prior austenite grain size against increasing welding speed. TEM micrographs affirmed the ferrite transformation and showed the presence of dense dislocations. The changes in hardness and tensile behavior under the experimental conditions were further reported.
关键词： High strength low alloy steel,Microstructure,Tensile strength,Laser beam welding
更新于2025-09-19 17:13:59
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Effect of Nd:YAG pulsed laser welding process on the liquation and strain-age cracking in GTD-111 superalloy
摘要： The weldability of GTD-111 nickel-based superalloy by Nd:YAG pulse laser with an average power of 250 W was studied using several pre- and post-weld heat treatment cycle, and the characteristics of liquation, solidification and strain-age cracks were also investigated. The results revealed that liquation cracks in the GTD-111 Nickel-Based Cast Superalloy were associated with the constitutional liquation of γ′ particle, MC carbides, inter-dendritic γ-γ? eutectic and melting of Cr-rich boride. Also, cracking during welding occurred at the places that the concentration of Al and Ti is high. Crack-free laser welds were observed in the MT1 conditions (1200 ℃ for 2 h) owing to dissolution of deleterious phases before welding. γ′ phase had little effect on the incidence of cracking in the MT1 condition. An analysis of the microstructures indicated that the cracking was caused primarily by liquation in the as-welded condition and was exacerbated by post-weld heat treatment cracking during the subsequent heat treatment. aging heat treatment of samples which were undergone aging heat treatment before welding, resulted in the formation of strain-age cracking due to γ? and γ-γ? eutectic phases precipitation. The results of micro-hardness indicated that the hardness of fusion zone (FZ) was higher than that of HAZ and base metal zone (BMZ). The liquation cracking in the heat affected zone (HAZ) was observed to be affected by the hardness of base-alloy.
关键词： Laser beam welding,GTD-111 superalloy,Liquation cracking,Strain age cracking
更新于2025-09-19 17:13:59
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Simulation and Experimental Based Analysis of the Laser Beam Welding of DP Steels
摘要： In this paper, heat affected zone characteristics of DP1000 steels was investigated during diode laser beam welding (LBW). A butt-welded joint of specimen in dimension of 300 x 150 mm each (according to EN15614-11:2002) with 1 mm thickness is used for the experimental purpose. The welding thermal cycle and the cooling circumstances in the HAZ was determined by real experiment and the physical simulation. A Gleeble 3500 thermo-physical simulator was used to physically simulate the coarse grain heat affected zone (CGHAZ) on the base material specimens by the utilization of the thermal cycles for t8/5 =2.5 s. The results of the physical simulation were validated by real welding experiments. The properties of the simulated and the real HAZ was examined by optical microscopic, scanning electron microscope and hardness tests.
关键词： Gleeble 3500 physical simulator,t8/5 cooling time,Laser beam welding (LBW),dual phase (DP) steel,Heat affected zone (HAZ) characterization
更新于2025-09-19 17:13:59
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Welding characteristics of butt-welded Inconel625 plate using CO2 laser beam
摘要： Inconel weldments are widely used in automobile and structural industries. In this study, the joints of Inconel625 are made with CO2 Laser beam welding process. The experimentation is carried out with two sets of process parameters varying the laser power and estimating the response of the welded component. Radiography analysis and distortion in the weldments are carried out. Distortion is measured using the Vernier height gauge. The lower the better-quality characteristics are chosen for distortion. The welds are free from flaws and the lower heat input results in the lower distortion.
关键词： Radiography,Distortion,Laser beam welding,Inconel625,Bead geometry
更新于2025-09-19 17:13:59
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The Studies of Plasma Torch Processes by Laser Beam Welding
摘要： The manufacturing of significant products with help of laser beam welding technologies requires higher stability characteristics of such technologies; this explains the necessity to run on-line testing procedures of through pro-melting process. This type of testing can be carried out by the registration of plasma streams that occur under a work piece by through pro-melting [i.e. metal undergoes an intensive laser beam thermal processing].
关键词： collectors of charged particles,plasma,informational-measuring system,plasma torch,analog-to-digital converter,ionization of metal vapor,welding of small thickness products,laser beam welding,through pro-melting
更新于2025-09-16 10:30:52
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Fatigue behaviour of a laser beam welded CoCrFeNiMn-type high entropy alloy
摘要： Laser beam welding was used to produce butt joints from the CoCrFeNiMn-type high entropy alloy. The alloy in the initial condition had an fcc single-phase coarse-grained structure. Laser welding resulted in the M7C3-type carbides precipitation in the fcc matrix. The carbide particles precipitation resulted in a considerable increase in microhardness from 150 HV 0.5 for the as-sintered condition to 205 HV 0.5 in the fusion zone. Laser beam welding had a negligible effect on both static mechanical properties and fatigue behaviour of the alloy. The endurance limit of either type of specimens (i.e. with and without welding seam) was 200 MPa. Fracture of all specimens with the laser beam welded seams occurred in the base material area during both tensile and fatigue testing. Weak effect of welding on static/fatigue behaviour of the alloy can be attributed to the higher hardness of the fusion zone, resulting in strain localization in the base material area. An increase in load resulted in activation of secondary slip systems and formation of deformation twins in fatigue specimens.
关键词： Fatigue,Tensile strength,Microstructure,Laser beam welding,High entropy alloy
更新于2025-09-16 10:30:52
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Fatigue Strength of Laser Beam Welded Steel-Aluminium Joints Considering Variable Amplitude Loading and Corrosive Environment
摘要： Hybrid material combinations of steel and aluminium are currently being joined by explosive welding in ship design, in order to reduce fuel consumption and increase transport weight. As an alternative to the elaborate and expensive explosive welding, a replacement for steel-aluminium adapters by means of laser beam welding in a lap joint configuration is being aimed at. Therefore, a laser beam welding process has been developed and optimised with regard to the different melting points and coefficients of thermal expansion of the materials as well as the formation of intermetallic phases due to the limited solubility of the elements. The characteristic of the weld seam, which is the result of a melt pool through the steel into the aluminium material, has a major impact on the quasi-static and cyclic strength of the joint. Especially the weld width and penetration depth have been identified as main influencing parameters. In the end, the developed laser beam welding process under spectroscopic control of the penetration depth is validated by fatigue investigations of lap joints and compact designed adapters. In addition to the fatigue strength under constant amplitude loading (CAL), the fatigue performance under variable amplitude loading (VAL) is particularly promising, even though the scatter increases from CAL to VAL and a linear damage accumulation is not applicable. A change in the fracture behaviour is explained by the intensity of the loading. Finally, the corrosion fatigue behaviour is shown by constant amplitude loading in a corrosive environment with a sodium chloride solution of 5 %, which causes a strength reduction from high cycle to long life fatigue.
关键词： steel-aluminium joint,ship building,corrosion fatigue,explosion welding,laser beam welding,lap joint,corrosive environment,ship design,constant amplitude loading,variable amplitude loading,compact adapter,fatigue assessment
更新于2025-09-12 10:27:22
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Process forces during remote laser beam welding and resistance spot welding – a comparative study
摘要： Welding of sheet metal in the automotive industry involves inflexible and expensive joining fixtures to properly position and fasten the parts that are to be joined. Feature-based fixturing is an approach to reduce fixtures in the assembly process. The approach relies on part-inherent fastening features that realize the functions of positioning and fastening. The proper design of these fastening features requires knowledge of forces that result from the joining process and thus need to be compensated. This paper describes the investigation of process forces during remote laser beam welding and during resistance spot welding. This is achieved by using a thermo-mechanical simulation model and experimental studies. The comparison shows significant differences in process forces that result from the two different processes. Finally, the results allow for the design of fastening features to reduce joining fixtures in the automotive body shop.
关键词： laser beam welding,fastening feature,process force,resistance spot welding,fixture
更新于2025-09-12 10:27:22
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Avoidance of end crater imperfections at high-power laser beam welding of closed circumferential welds
摘要： The present work deals with the development of a strategy for the prevention of end crater defects in high-power laser welding of thick-walled circumferential welds. A series of experiments were performed to understand the influence of the welding parameters on the formation of end crater defects such as pores, cracks, root excess weld metal and shrinkage cavities in the overlap area. An abrupt switch-off of the laser power while closing the circumferential weld leads to a formation of a hole which passes through the whole welded material thickness. A laser power ramp-down causes solidification cracks which are initiated on the transition from full-penetration mode to partial penetration. Defocusing the laser beam led to promising results in terms of avoiding end crater defects. Cracks and pores in the overlap area could be effectively avoided by using defocusing techniques. A strategy for avoiding of end crater imperfections was tested on flat specimens of steel grade S355 J2 with a wall thickness of between 8 and 10 mm and then transferred on the 10 mm thick pipe sections made of high-strength pipeline steel API5L-X100Q.
关键词： Thick-walled pipes,End crater,Circumferential weld,High-power laser beam,Laser beam welding
更新于2025-09-12 10:27:22