- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Characterization of laser beam offset welding of titanium to steel with 38Zn-61Cu alloy filler
摘要： Laser welding of TC4 Titanium (Ti) alloy to 304 austenitic stainless steel (SS) has been applied using 38Zn-61Cu alloy as filler metal. A new welding process for SS-Ti alloy joint was introduced on the basis of the controlling the formation of Ti-Fe intermetallics in the joint. One pass welding involving creation of a joint with one fusion weld and one diffusion weld separated by remaining unmelted Ti alloy. When laser beam on the Ti alloy side was 1.5 mm, Ti alloy would not be completely melted in joint. Through heat conduction of unmelted Ti alloy, the atomic diffusion occurred at the SS-Ti alloy interface. A diffusion weld was formed at the SS-Ti alloy interface with the main microstructure of β-CuZn + Fe3Zn7, β-CuZn and Ti2Zn3 + Ti3Cu4. The joint fractured at the diffusion weld with the maximum tensile strength of 128 MPa.
关键词： Diffusion welding,Microstructure,TC4 Ti alloy,Filler metal,304 austenitic stainless steel,Laser welding
更新于2025-09-19 17:13:59
-
Prediction of Preheating Temperatures for S690QL High Strength Steel Using FEM-Simulation for High Power Laser Welding
摘要： This study investigates a method for predicting the effect of preheating temperatures on the resulting hardness for high power laser welding of high strength steel. An FEM model is introduced containing a hardness calculation based on an existing model. Moreover, the hardness values of experimental results have been measured in order to show the performance of the model. The hardness calculation requires the chemical composition and the t8/5-time at the point of measurement. It is claimed that a calibration of the melt pool width and depth at room temperature only is enough to get reasonable results from the FEM-model for higher preheating temperatures. From the experimental result of a single experiment the width of a weld seam and the depth was deducted. In this study experiments have been done at various preheating temperatures in order to show the correlation between the model and the experimental results at various temperatures. The hardness equation provides suitable results in the verification with the measurements. The prediction of preheating temperature can be done with the resulting t8/5-time of the FEM-model. This method can decrease the amount of time and costs within a production according to testing and analyzing a matrix of process parameters. Moreover it is concluded that this methodology might be used for single item production.
关键词： Deep penetration laser welding,FEM-welding simulation,High strength steel,Preheating,Predicting hardness
更新于2025-09-19 17:13:59
-
POST WELD HEAT TREATMENT OF NiTinol SHAPE MEMORY ALLOY USING LASER POWER SOURCE
摘要： In this work, attempt is made to carry out post weld heat treatment (PWHT) on NiTinol samples using laser power source. Initially, 1 mm thick NiTinol sheets were welded in butt joint position using Ytterbium: Yttrium aluminum garnet (Yb: YAG) laser power source. Laser welding was carried out in continuous mode, and the quality of the weld was assessed with respect to phase transformation temperatures, microhardness, tensile strength, and corrosion resistance. To improve the quality of the welded samples, PWHT was done by passing a laser beam over the welded samples. It was found that PWHT had a significant effect on the phase transformation temperatures, microhardness, tensile strength and corrosion behavior of the welded NiTinol joints.
关键词： laser heat treatment,NiTinol,laser welding,mechanical properties,corrosion behavior
更新于2025-09-19 17:13:59
-
Microstructure of intercritical heat affected zone and toughness of microalloyed steel laser welds
摘要： Microstructure of laser welds of the X70 low-carbon pipe steel was studied. High cooling rates after laser welding and non-uniform distribution of carbon in the ferrite-pearlite base metal caused formation of regions with increased microhardness (up to 650 НV) in inter-critical heat affected zone (ICHAZ). These regions consisted of finely dispersed degenerate upper bainite and martensite-austenite constituents of a slender shape and small fraction of a massive shape along the boundaries of bainite laths, as well as twinned martensite. High concentration of martensite-austenite constituents (10–16%) and residual stresses in ICHAZ, as well as a dendritic martensitic structure with carbide interlayers along the boundaries of martensite laths in fusion zone were the main reasons of sharp decrease in charpy impact energy of the welded samples. High microhardness of the laser welds was decreased down to 320 HV and their brittleness was improved by annealing. Also, in ICHAZ, degenerate upper bainite and the regions of martensite-austenite constituents decayed forming tempered sorbite and Fe2C and Fe3C carbides, respectively. Charpy impact energy of the welds doubled after annealing compared to the welds without annealing, and ductile-brittle transition temperature decreased down to –60 °С.
关键词： Toughness,Heat affected zone,Structure,Laser welding,Low-carbon steel
更新于2025-09-19 17:13:59
-
Numerical and experimental study on the molten pool dynamics and fusion zone formation in multi-pass narrow gap laser welding
摘要： The development and evolution of molten pools provide valuable insight into the complexity of multi-pass narrow gap laser welding (NGLW) process. However, in-situ monitoring of the molten pool characteristics proves to be challenging in NGLW due to the existence of the narrow and deep groove. In this study, a three-dimensional transient model coupled with a self-adaptive Gaussian heat source was employed to help understand the molten pool behaviour and fusion zone formation during multi-pass NGLW process. Three weld bead profiles including convex, flat and concave were investigated by varying the process parameters. With more passes being processed, the shape of the molten pool transformed from teardrop to an elliptical one with increased tailing edge angles; contact angle of the cross-section decreased, demonstrating welds with more concave profiles. In order to obtain the fusion zone of the welds, enthalpy-porosity method was used to overlay liquid fraction of the cross-section over the complete melting and solidification process. Compared with the previous passes, the last filling pass presented a different molten pool morphology, contributing to variant top surface geometries. Final fusion zone of multi-pass NGLW was achieved by combining the fusion zone of each separate pass. The simulated results were compared with experiments.
关键词： CFD,Narrow gap laser welding (NGLW),Multi-pass,Fusion zone,Molten pool
更新于2025-09-19 17:13:59
-
Influence of Post-Weld Processing Techniques on Laser Beam-Welded Ala??3Mga??0.25Sc Alloy Sheets
摘要： Fusion welding in aluminium alloys had always remained an issue for aero- and auto industries. An Al–3Mg–0.25Sc alloy is classi?ed as weldable aluminium alloys. In this study, two welding techniques, keyhole and conduction welding, have been used for joining Al–3Mg–0.25Sc sheets of thickness 1.6 mm. Experiments were carried out using different beam diameter (0.16–2 mm dia), beam power (2–4.5 kW) and laser head speed (ranging from 0.5 to 6 m/min). The results for all autogenous keyhole welding clearly demonstrated a drop in ductility (\ 0.8%) compared to base metal for all beam power and welding speed combinations although the yield strength was reasonably good (175–180 MPa, i.e. [ 50% of base metal). Residual stress-induced distortions affected the ?nal shape of the product, and for that, a suitable stress relief annealing was also required. Hereby, we chose two heat treatment schedules: (1) solution treatment and annealing and (2) retrogression and re-ageing. Retrogression and re-ageing is a precipitation-controlled phenomenon and comprises of an intermediate annealing step between tempering and solutionizing temperature to dissolve the nano-clusters present in the matrix (retrogression) and re-precipitating and growing them by ageing (re-ageing). These two steps were repeated cyclically, and as a result, the strength (190 MPa) and ductility (* 9%) of the material were improved substantially. The improvement of ductility and strength was explained in detail in the light of microstructural studies.
关键词： Strength,Post weld treatment,Weldment,Al-3Mg-0.25Sc alloy,Ductility,Laser welding
更新于2025-09-19 17:13:59
-
Design of laser welding applied to T joints between steel and aluminium
摘要： Laser conduction welding was used to directly join DH36 steel to AA5083 aluminium alloy in a T joint configuration, each plate with 6 mm of thickness. The effect of the process energy (via power density and interaction time) on the joint integrity and quality in terms of cracking, porosity and intermetallic compound layer formation was investigated. Successful T joints were produced by melting of the aluminium plate, which was inserted into a 4 mm deep groove machined on the steel plate, with the heat generated by the laser irradiation on the steel surface. The IMC layer thickness was less than 5 μm. Although cracking was observed along the IMC layer with higher levels of energies, the joints were still strong due to the mechanical inter-locking effect resulting from the novel design of the component, whereby the IMCs were subjected to compressive state of stress while loading.
关键词： Aluminium,Dissimilar metal joining,Steel,Joint design,Laser welding,T joint,Intermetallic compounds
更新于2025-09-19 17:13:59
-
Overlap joining of aluminium and copper using laser micro welding with spatial power modulation
摘要： The rising demand for high power battery systems for the electric mobility requires the connection of a large number of cells. Due to the functionality of the cell chemistry, a combination of copper and aluminium is necessary. The differing material properties like thermal conductivity as well as the formation of intermetallic phases are challenging for welding processes. This study contains the results for overlap joints of copper and aluminium using a laser beam welding process with spatial power modulation. With a parameter variation, the cross-sectional shape of the weld seams and therefore, the ratio of depth to width can be adjusted. With additional longitudinal cross sections and an energy-dispersive X-ray spectroscopy analysis, the different mixing behaviour of the dissimilar material depending on the top layer is investigated.
关键词： Laser welding,Spatial power modulation,Micro joining,Battery,Aluminium,Copper
更新于2025-09-19 17:13:59
-
[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Analysis of The Main Hydrodynamic Mechanisms in Laser Induced Keyhole Welding
摘要： Adequate modeling of additive laser technologies and laser welding requires a comparative analysis of the main hydrodynamic mechanisms and modes. The melt hydrodynamics during laser processing can be generated by the vapor recoil pressure and the thermocapillary effect. Analysis of the measured values of melt flow velocity at the front wall of keyhole and other measured parameters accompanying the welding allows to reveal the role of each mechanism. It is shown that the hydrodynamics in this case are determined by the thermocapillary shear flow in the thin surface layer at the negligible evaporation.
关键词： keyhole hydrodynamics,Additive technology,laser welding
更新于2025-09-19 17:13:59
-
Optimization of welding parameters in laser welding of Ti6Al4V using VIKOR optimization method
摘要： Ti6Al4V alloys are widely preferred in the biomedical industries owing to its higher corrosion resistance in human body environment. Welding plays a critical role in the manufacture of complicated biomedical components. Hence, the necessity to identify suitable joining process for joining Ti6Al4V is very important. In this work, an attempt is made to study the CO2 laser welding of titanium sheets (Ti6Al4V) having dimensions of 100 (cid:1) 60 (cid:1) 3 mm. Laser welding was done based on L9 Taguchi array with welding speed (v), laser power(P), and shielding gas ?ow rate(f) as input parameters. The weld quality was analysed by measuring the depth of penetration (DOP), bead width (BW), and hardness values. Full penetration was observed only in two welding trials. The optimized parameters were identi?ed by using the VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) multi-objective optimization technique. Analytic Hierarchy Process (AHP) is used for determining the weights of the relative importance of the output factors. VIKOR method identi?ed that the 7th experimental run (power = 1.3 kW, speed = 0.3 m/min, shielding gas ?ow rate = 20 L/min) as the optimized parameter for getting the weld with full depth of penetration, lesser bead width, higher microhardness values in the fusion zone (FZ) and heat affected zone (HAZ). The metallurgical characterization of the optimized weld is also dicussed with the aid of microstructures taken from Scanning Electron Microscope (SEM).
关键词： CO2 laser welding,Hardness values,Bead geometry,VIKOR multi-objective optimization technique,Ti6Al4V
更新于2025-09-19 17:13:59