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Local heat treatment of a laser build-up
摘要： Laser cladding or laser metal deposition involves the deposition of any weldable material onto the surface of a metal substrate by means of a laser beam. Although clad deposits are fully fusion-joined to the substrate material, the very low heat-input associated with laser cladding results in extremely low dilution as well as relatively small heat-affected zones (HAZ). Subsequent to the clad-repair process, heat treatment is normally not necessary, but some critical components may require it due to the high hardness obtained in the HAZ. Conventional heat treatments are most often time-consuming, costly and could cause possible distortion of the component. In this study local laser heat treatment of the HAZ after laser cladding has been investigated on different substrate materials (21CrMoV5-11, X22CrMoV12-1, 34CrNiMo6) as an alternative to full post-weld heat treatment (PWHT). Due to the focused heat of the laser beam, the required time at temperature for heat treatment was only a fraction compared to that of conventional heat treatments. It was observed that the HAZ hardness could indeed be lowered significantly by controlling the temperature and interaction time of the local treatment. For 21CrMoV5-11 the HAZ hardness was decreased to below 400 HV with most treatments at 800 °C, but the 8 s interaction time was found to be optimal. The X22CrMoV12-1 material showed the highest resistance to PWHT and only the longest interaction time at 800 °C resulted in HAZ hardness close to 400 HV. The largest decrease in HAZ hardness was obtained with the 34CrNiMo6 material and the longest interaction time at 700 °C resulted in the lowest hardness.
关键词： heat-affected-zone,hardness,local heat treatment,Laser,cladding
更新于2025-09-12 10:27:22
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Numerical analysis of the thermally induced damage in remote laser cut carbon fibre reinforced polymers
摘要： Remote laser cutting in carbon fibre reinforced polymers is a promising machining technology which can reduce the main drawback in laser cutting, the heat affected zone. This contribution presents a two-step modelling approach for the simulation of remote laser cut carbon fibre reinforced polymers, consisting of a damage model for the initially intact material and a model for the thermally damaged material. The static damage behaviour was modelled with the Pinho material model [1], which stands out due to its physically based failure criteria. Initial thermal damages caused by the heat input were modelled with the damage parameters of the Pinho model. The dimensions of the heat affected zone are taken from polished microsections of the material around the cutting edge. As a numerical example, comparative tensile tests of milled and laser cut open hole specimens were simulated. The advantage of these specimens is the notch effect around the holes in the heat affected zone, which amplifies the differences between the two cutting technologies.
关键词： remote laser cutting,heat affected zone,damage model,Pinho material model,carbon fibre reinforced polymers
更新于2025-09-12 10:27:22
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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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Laser dimple texturing – applications, process, challenges, and recent developments: a review
摘要： Laser dimple texturing has been a surge in the surface to surface contact applications like the cutting tool/workpiece interaction, piston-cylinder assembly, bearings, prosthetic hip & knee joints, blanking punch- die assembly, etc. to control the friction and wear between the interactions. In this article, the first part presented about a broad literature review on an effect of dimple texture in various industrial applications like bio-implant components and cutting tools. In the second part, detailed information has discussed on a process of laser dimple texturing and influence of laser process parameters such as laser wavelength, laser energy, number of pulses, pulse duration and focal distance on dimple geometry. The third part describes a comprehensive literature review on challenges/limitations of laser dimple texturing process like heat affected zone, tensile residual stresses, bulges around the dimple, etc. Finally, in the fourth part, proper attention has given on recent developments like laser shock peen texturing, laser texturing under water and post-processing techniques to overcome the limitations of laser surface texturing process.
关键词： Friction,Hip & knee joints,Wear,Cutting tool,Laser peen texturing,Heat affected zone,Laser dimple texture
更新于2025-09-12 10:27:22
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Optimization of process parameter of Laser beam machining of high strength steels: a review
摘要： Metal cutting forms the basis of industry its relevance among products of everyday life due its high strength application in structural, aviation, aerospace, military, naval purpose etc. Based on recent study it is found that many high strength steel are cut using lasers and it has given exceptional result as compared to other Non conventional machining process it is important to know how the cutting is affecting the material properties and which parameters are responsible for such change. The various parameters and their effects are shown in the given study which is analyzed by different researchers along the course of time. The material and thickness and different optimization techniques by different researchers is also shown.
关键词： Macro structural changes,CO2,Control parameters,laser beam cutting (LBC),Heat Affected Zone (HAZ),Micro
更新于2025-09-12 10:27:22
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Heat-Affected Zone Investigation During the Laser Beam Drilling of Hybrid Composite Using Statistical Approach
摘要： In the present work, basalt–glass hybrid composite has been fabricated and machined using laser beam drilling, to predict a safe machining zone pertaining to high drill quality with minimum heat-affected zone and maximum hole circularity. The prediction of the zone has been done by mathematical modeling using response surface methodology. The obtained zone has also been validated by performing more experiments. Moreover, the dependency of hole circularity and heat-affected zone on input parameters has also been discussed. From the results, it is evident that the obtained zone is capable of minimizing the heat-affected zone with acceptable hole circularity. Moreover, the behavior of input parameters is non-monotonic in nature.
关键词： Precise drilling,Heat-affected zone,Basalt–glass composite,Hybrid composite
更新于2025-09-12 10:27:22
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Coaxial waterjet-assisted laser drilling of film cooling holes in turbine blades
摘要： Film cooling holes (FCHs) of nickel-based single crystal turbine blades were drilled by 532 nm Nd:YVO4 nanosecond laser in coaxial waterjet-assisted environment. Microstructure of the side wall of the FCHs was mainly investigated by means of transmission electron microscopy. The average thickness of heat affected zone (HAZ) around FCHs decreases with increasing of water flow rate. The main phase within HAZ evolves from β-NiAl to β-NiAl + γ-Ni with the increase in the water flow rate. Some γ-Ni particles in the HAZ twined along (111) plane. A small portion of the FCHs are free of HAZ when drilled by coaxial waterjet-assisted laser drilling at a laminar water flow rate ≥ 3.1 m/s. There are no processing-induced defects including HAZ, microcrack, and phase transformation around the FCHs when drilled at the water flow rate ≥ 5.1 m/s. The FCHs with high surface quality can be drilled by the coaxial waterjet-assisted laser drilling. Finally, effects of fluid water on drilling quality of the FCHs were discussed.
关键词： turbine blades,film cooling holes,Coaxial waterjet-assisted laser drilling,heat affected zone (HAZ),transmission electron microscopy (TEM)
更新于2025-09-11 14:15:04
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Calculation and experimental determination of the geometric parameters of the coatings by laser cladding
摘要： In the present work the experiments on laser cladding of powder Fe-B-Cr-6-2 on samples of steel 20. Metallographic studies of geometric parameters of deposited layers and the depth of the heat affected zone (HAZ). Using is the method of full factorial experiment (FFE) mathematical dependences of the geometrical sizes of the deposited layers of processing modes. Deviation of calculated values from experimental data is not more than 3%.
关键词： geometric parameters,laser cladding,heat affected zone,full factorial experiment
更新于2025-09-10 09:29:36