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Welding of Dissimilar Steel/Al Joints Using Dual-Beam Lasers with Side-by-Side Configuration
摘要： Welding of dissimilar steel/Al lapped joints of 1.5 mm in thickness was carried out by using dual-beam laser welding with side-by-side configuration. The effect of the major process parameters including the dual-beam power ratio of (Rs) and dual-beam distance (d1) on the steel/Al joint characteristics was investigated concerning the weld shape, interface microstructures, tensile resistance and fracture behavior. The results show that dual-beam laser welding with side-by-side configuration produces soundly welded steel/Al lapped joints free of welding defects. The processing parameters of Rs and d1 have a great influence on the weld appearance, the weld penetration in the Al alloy side (P2) and the welding defects. Variation in the depth of the P2 and the locations at the Al/weld interface cause heterogeneous microstructures in the morphology and the thickness of the intermetallic compound (IMC) layers. In addition, electron back scattered diffraction (EBSD) phase mapping reveals that the IMC layer microstructures formed at the Al/weld interface include the needle-like θ-Fe4Al13 phases and compact lath η-Fe2Al5 layers. Some very fine θ-Fe4Al13 and η-Fe2Al5 phases generated along the weld grain boundaries of the steel/Al joints are also confirmed. Finally, there is a matching relationship between the P2 and the tensile resistance of steel/Al joints, and the maximum tensile resistance of 109.2 N/mm is obtained by the steel/Al joints produced at the Rs of 1.50 during dual-beam laser welding with side-by-side configuration. Two fracture path modes have taken place depending on the P2, and relatively high resistance has been achieved for the steel/Al joints with an optimum P2.
关键词： dual-beam laser welding,tensile resistance,side-by-side configuration,EBSD phase mapping,steel/Al joint
更新于2025-11-28 14:24:20
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Effects of Substrate Preheating Temperatures on the Microstructure, Properties, and Residual Stress of 12CrNi2 Prepared by Laser Cladding Deposition Technique
摘要： The 12CrNi2 alloy steel powder studied in the present paper is mainly used to manufacture camshafts for nuclear power emergency diesel engines. Laser cladding deposition is of great signi?cance for the manufacture of nuclear power emergency diesel camshafts, which has the advantages of reducing material cost and shortening the manufacturing cycle. However, due to the extremely uneven heating of the components during the deposition process, a complex residual stress ?eld occurs, resulting in crack defects and residual deformation of the components. In the present paper, 12CrNi2 bulk specimens were prepared on the Q460E high-strength structural steel substrate at different preheating temperatures by laser cladding deposition technique, and a ?nite element residual stress analysis model was established to investigate the effects of different preheating temperatures on the microstructure, properties, and residual stress of the specimens. The results of the experiments and ?nite element simulations show that with the increase of preheating temperature, the content of martensite/bainite in the deposited layer decreases, and the ferrite content increases. The proper preheating temperature (150 ?C) has good mechanical properties. The residual stress on the surface of each specimen decreases with the increase of the preheating temperature. The longitudinal stress is greater at the rear-end deposition part, and the lateral residual stress is greater on both sides along the scanning direction.
关键词： substrate preheating,12CrNi2 alloy steel powder,residual stress,laser cladding deposition,microstructure and properties
更新于2025-11-28 14:24:20
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Laser cooling arc plasma effect in laser-arc hybrid welding of 316L stainless steel
摘要： Current laser-plasma interaction theory supports that the plasma energy e.g. electron temperature would increase by the effect of inverse bremsstrahlung (IB) absorption, when a laser beam passed through the plasma. However, in this paper, we found an interesting laser cooling arc plasma effect (LCAPE) during kilo-Watt fiber laser-TIG hybrid welding. Based on theoretical modelling and experiments, we observed that a temperature decrease of more than 5000 K at the tail of the argon plasma occurred under different process parameters during hybrid welding of 316L stainless steel. We proposed the LCAPE is caused by the laser-induced metal vapor. The mechanism mainly includes the convection cooling and enhanced radiation of the arc plasma by the metal vapor. Our findings could broaden the theory of laser-plasma interaction and provide a theoretical reference to the modulation and control of plasma in industries.
关键词： Cooling effect,Stainless steel,Laser-arc hybrid welding,Arc plasma,Fiber laser
更新于2025-11-28 14:24:20
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[Communications in Computer and Information Science] Data Mining Volume 996 (16th Australasian Conference, AusDM 2018, Bahrurst, NSW, Australia, November 28–30, 2018, Revised Selected Papers) || Effect of Nickel Foil Thickness on Microstructure and Microhardness of Steel/Aluminium Alloy Dissimilar Laser Welding Joints
摘要： Laser lap welding between DP980 steel and 6061 aluminum alloy was carried out using IPG YLS-6000 fiber laser, nickel foil with different thickness (0.10, 0.20 and 0.30 mm) was used as interlayer. The microstructure was observed by SEM, EDS was used to determine the distribution of elements and intermetallic compounds types, and the hardness was determined by HV1000IS. The results showed that the microstructure in weld seam (WS) and fusion line (FL) of welded joint without nickel foil was d ferrite and lath martensite (LM). For welded joints with nickel interlayer, the d ! c phase transition was promoted by nickel elements. Thus, with the thickness of the nickel foil increased, the content of nickel elements in weld pool increased, resulting in decrease of d ferrite content in WS and FL. Meanwhile, the microstructure in WS and FL was full LM when the thickness of the nickel foil was 0.30 mm. Meanwhile, the NixAly IMC was found in interface, which inhibited Fe–Al metallurgical reaction and reduced the thickness of Fe–Al IMC. Therefore, with nickel foil thickness increased, the content of nickel elements and the NixAly IMC increased. Moreover, the maximum thickness of the IMC layer was able to reduce to 10.66 when the thickness of the nickel foil was 0.10 mm. With the reduction of d ferrite content in WS and FL, the microhardness in WS increased with the thickness of the nickel foil increased. However, because the NixAly IMC was a soft phase, the microhardness in interface decreased, significantly.
关键词： Steel,Processing,Aluminum,Laser welding
更新于2025-11-28 14:24:20
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Characteristics of multi-pass narrow-gap laser welding of D406A ultra-high strength steel
摘要： A universal and applicable method to predict bonding quality in narrow-gap laser beam filler wire welding of D406A ultra-high strength steel was presented. Defect-free joint could be achieved under the predicted optimal welding condition, while the production efficiency of narrow-gap laser beam filler wire welding under optimized welding condition was about 3.75 times that of traditional tungsten arc welding currently used in practical industry. Compared with the tungsten arc welding joint, microstructure in the fusion zone of laser welded joint was more uniform, which brought out a less fluctuation in the microhardness of fusion zone along the thickness direction. The tensile strength of as-welded laser welding joint was slightly higher than that of as-welded tungsten arc welding joint while the elongation of the former increased by 15.9% over that of the latter. A binocular stereo three-dimensional scanning method was adopted to compare the residual distortion of D406A joints between laser welding and tungsten arc welding. Notably, the distortion of laser welded joint was about 21% of that of the tungsten arc welding joint. Narrow-gap laser filler wire welding is a feasible substitute for conventional tungsten arc welding in the fabrication of welded construction of D406A steel.
关键词： ultra-high strength steel,welding distortion,filler wire,narrow-gap laser beam welding,microstructure
更新于2025-11-28 14:24:20
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Analysis of properties laser welded RAK 40/70 steel sheets
摘要： Both, the ecological production and operation of vehicles demand using such materials for deformation zones’ structural parts, which show some specific properties and use innovative technologies to process them. Specific requirements for functionality (strength, stiffness, deformation work, fatigue properties) are closely linked to processability (formability). In the paper are presented results for multiphase TRIP steel RAK40/70 when welded by pulse solid-state fiber laser YLS-5000. Based on microstructure analysis in the fusion zone and heat affected zone the welding parameters were optimised. The influence of laser welding on the strength and deformation properties was verified by characteristics of strength, stiffness and deformation work, as they were calculated from mechanical properties measured by tensile test and three-point bending test. The knowledge gathered in the field of laser welding influence on the strength and deformation properties of multiphase TRIP steel RAK40/70 should help designers when design the lightweight structural parts of the car body.
关键词： mechanical properties,TRIP steel,RAK 40/70,microstructure,laser welding
更新于2025-11-28 14:24:20
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Evaluation of fluences and surface characteristics in laser polishing SKD 11 tool steel
摘要： In this paper, a continuous-wave laser beam from a multimode fiber laser was applied to study the polishing effect. Three kinds of surface morphologies were acquired by fast-speed (FS) & lower-speed (LS) wire electrical discharge machining (EDM), milling processing methods on SKD11 tool steel. Then influence of laser fluence on the polished surface characteristics was analyzed. The results showed that surface roughness parameters (Ra, Rz, Rt, and Sa) can be significantly affected by this effect. With laser fluence increasing, the polished surface underwent a comprehensive topographical evolution from superficial surface melting to surface over-melting. The improvements by FS-EDM, LS-EDM, and milling in roughness were 86.83%, 90.70% and 86.07%, respectively. The corresponding laser fluences were 14.26 J/mm2, 12.73 J/mm2 and 13.55 J/mm2, indicating that LS-EDM tool steel surface has the best polishing effect. The comparative statistical results of the bearing area curve, bidirectional reflectance distribution function, and power spectral density from the LS-EDM surfaces showed the best polishing results. In addition, all the pre-prepared surfaces could be polished to Ra < 0.5 μm using high polishing velocities. These findings also signified that laser beam with top-hat distribution has a great potential for high-efficiency polishing of tool steel surfaces.
关键词： Power spectral density,Surface morphology,Bearing area curve,Fluence,Laser polishing,Tool steel
更新于2025-11-28 14:24:20
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Butt welding-brazing of steel to aluminum by hybrid laser-CMT
摘要： A laser penetration welding-brazing combined with Cold Metal Transfer (CMT) arc, was proposed to improve weld shape and interfacial reaction inhomogeneity of 5052 aluminum alloy and Q235 low carbon steel with ER5356 welding wire in butt joint. The effects of wire feed speed, beam offset and welding speed on weld shape, interfacial microstructures and tensile strength of joints was studied. This method improved the undercut defect existed in butt laser welding-brazing, obtained well-formed joints and promoted the uniform distribution of the interface reaction. The interfacial intermetallic compounds (IMCs) layer consisted of Fe2Al5 and Fe4Al13 and the thicknesses were controlled to 3-5 μm. Microstructures of weld seam was composed of α-Al and Al3Mg2. The brittle IMCs layer thickened and then the tensile strength decreased with increasing the wire feed speed. The thickness of the IMCs layer decreased but weld shape became worse when the welding speed or the offset increased. The tensile strength increased first and then decreased. The highest tensile strength reached higher than 80 MPa and the joint fractured in IMCs layer along the interface.
关键词： intermetallic compound,Laser–CMT arc hybrid welding-brazing,dissimilar metals welding,low carbon steel,aluminum alloy
更新于2025-11-28 14:24:20
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Hybrid laser-metal inert gas keyhole welding of thick steel/Al butt joints
摘要： Dissimilar joining of steel/Al joints has become more and more signi?cant in industrial applications with particular weight saving interest. However, directly welding of steel/Al joints even in thin thickness is very di?cult. In the present study, the hybrid laser-metal inert gas (MIG) source focused on the steel side in keyhole mode was introduced to weld steel/Al butt joints of 6 mm in thickness. E?ects of the laser o?sets on the weld shape, interface microstructures, and ultimate tensile strength (UTS) of the steel/Al joints were investigated. Sound steel/Al butt joints were obtained by using this hybrid laser-MIG keyhole welding process. By increasing the laser o?sets from 0.6 and 0.8 mm, the welds exhibited a better shape with a smooth appearance attributable to the reduced heat input. The positions through the thickness of the steel/Al joints played an important role in the morphology and thickness of the intermetallic compound (IMC) layers at the Al/weld interface. The IMC layers had a thick irregular morphology at the upper part and the lower part, while the layers at the middle part exhibited a relatively thin and uniform morphology. With some certain welding conditions, the Al/weld interface at the lower part of the steel/Al joints transformed to a welding-brazing mode from a fusion one. The island-shape structures were formed at the Al/weld interface, and the IMC layers were composed of Fe2Al5 layer and needlelike Fe4Al13 phases. The maximum UTS of 87.0 MPa was obtained at a laser o?set of 0.6 mm. Although the failure occurred in the IMC layers revealed a brittle fracture, the fracture morphology and locations were a mixed failure, which had a certain resistance to the crack propagation of the IMC layers.
关键词： laser-metal inert gas welding,ultimate tensile strength,keyhole welding,intermetallic compound,steel/Al joints
更新于2025-11-28 14:24:20
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Influence of Al-Si coating on microstructure and mechanical properties of fiber laser welded 22MnB5 steel
摘要： Fiber laser welding of as-received 22MnB5 steel with Al-10wt.%Si coating in butt configuration was performed. The influence of Al-Si coating on microstructure transformation and mechanical properties including tensile tests, fatigue tests and Erichsen cupping tests was investigated. Ferrite with Al enrichment (1.37 wt%) was found in the fusion zone (FZ) of coated welded joints with 15% area proportion, while nearly entire martensite structure composed the FZ in the case of de-coated joint. The strain localization was more likely to accumulate at the martensite/martensite interface rather than the ferrite/martensite interface due to the higher kernel average misorientation (KAM) values. Microhardness of the FZ in coated welded joints dropped by 50HV compared with that of de-coated welded joints. However, tensile properties were not affected since failure occurred at base metal (BM). Fatigue samples of coated welded joints showed better performance than the de-coated ones, suggesting that the ferrite in the FZ had positive effect on fatigue lives under cycling load conditions. The Erichsen cupping tests showed similar Erichsen values (5.60 mm and 5.67 mm) for de-coated and coated welded joints. An opposite effect of ferrite on Erichsen cupping tests was obtained. The peak force required for deformation dropped by 35% with Al-10wt.%Si coating.
关键词： Microstructure,Al-Si coating,Mechanical properties,Fiber laser welding,22MnB5 steel
更新于2025-11-28 14:24:20