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Tom Eller - One of the best experts on this subject based on the ideXlab platform.
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plasticity and fracture modeling of the heat Affected Zone in resistance spot welded tailor hardened boron steel
Journal of Materials Processing Technology, 2016Co-Authors: Tom Eller, Lars Greve, M T Andres, M Medricky, H J M Geijselaers, Vincent T Meinders, Van Den A H BoogaardAbstract:tFive hardness grades of 22MnB5 are considered, covering the full strength-range from 600 MPa in theferritic/pearlitic range to 1500 MPa in the fully hardened, martensitic state. These five grades form thebasis for a hardness-based material model for the heat-Affected Zone found around resistance spot weldsin tailor hardened boron steel. Microhardness measurements of resistance spot welds in all five gradesare used to determine the location and shape of the heat-Affected Zone and for mapping of the hardnessdistributions into FE-models of the specimens used for model calibration. For calibration of the strainhardening of the heat-Affected Zone, a specially designed asymmetric uni-axial tensile specimen is usedthat features a well-defined strain field up to fracture initiation. Both the measured force–displacementcurves and the strain fields are used as input for an inverse FEM optimization algorithm that identifiessuitable strain hardening model parameters by minimizing the differences between experimental andsimulated results. A strain-based fracture model is calibrated using a hybrid experimental/numericalapproach, featuring two additional specimens in which fracture initiates in the HAZ under differentstress states. Strain hardening and fracture strains are assumed to be linearly related to the as-weldedmaterial hardness. The calibration and modeling approach are validated by comparing measured andpredicted force–displacement curves and strain fields of welded coupon tensile tests.
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the softened heat Affected Zone in resistance spot welded tailor hardened boron steel a material model for crash simulation
International Conference on Impact Loading of Structures and Materials (ICILSM): International Conference on Impact Loading of Structures and Material, 2016Co-Authors: Tom Eller, Lars Greve, M T Andres, M Medricky, H J M Geijselaers, Vincent T Meinders, Antonius H Van Den BoogaardAbstract:A hardness-based model for tailor hardened boron steel is presented that takes into account the softened heat-Affected Zone of resistance spot welds. The computational model is designed for crashworthiness simulation of fully and partially hardened components obtained by tailored tooling. Five different hardness grades of 22MnB5 are used for model calibration. The proposed model is validated with a specially designed tapered tensile test specimen with hardness transition Zone and resistance spot weld in the gauge section.
S K Albert - One of the best experts on this subject based on the ideXlab platform.
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influence of boron on microstructure and mechanical properties of gleeble simulated heat Affected Zone in p91 steel
International Journal of Pressure Vessels and Piping, 2020Co-Authors: Akhil Khajuria, Modassir Akhtar, Raman Bedi, Rajesh Kumar, M Ghosh, C R Das, S K AlbertAbstract:Abstract In the present endeavor, a Gleeble thermo-mechanical simulator has been used to simulate subZones of the heat-Affected Zone (HAZ) of boron-free P91 and boron-modified P91B steels to investigate the influence of boron on microstructure and mechanical properties. The prior austenite grain (PAG) size remained similar to that of parent metal in the fine-grained heat-Affected Zone (FGHAZ) and inter-critical heat-Affected Zone (ICHAZ) of P91B steel. The microhardness value of simulated specimens, including parent metals was observed to be similar. But impression creep resistance of boron-containing steel was significantly higher than that of the boron-free steel. The presence of boron decreased precipitates size and increased fraction of low energy Σ3 coincident-site lattice (CSL) boundaries that attributed to improvement of creep resistance. However, there was a slight reduction in solid solution hardening due to increased area fraction of precipitates in parent metal and simulated specimens of boron-containing steel. Hindering of alloy element partitioning during impression creep of P91B-ICHAZ was observed, which was possibly due to the presence of boron in soluble form in the iron matrix and the segregated form on grain and sub-grain boundaries (SGBs). Further, the addition of boron was observed to retard M23C6 precipitate coarsening in the P91B-ICHAZ in comparison to its P91 version.
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microstructural investigations on simulated intercritical heat Affected Zone of boron modified p91 steel
Materials Science and Technology, 2020Co-Authors: Akhil Khajuria, Modassir Akhtar, Raman Bedi, Rajesh Kumar, M Ghosh, C R Das, S K AlbertAbstract:Conventional P91 and boron modified P91-steels were considered in the present investigation. Using Gleeble, weld intercritical heat-Affected Zone (ICHAZ) was processed. Conventional microscopy was ...
Mahadev Shome - One of the best experts on this subject based on the ideXlab platform.
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Effect of heat-input on austenite grain size in the heat-Affected Zone of HSLA-100 steel
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2006Co-Authors: Mahadev ShomeAbstract:Abstract The prior-austenite grain size in the heat-Affected Zones of single-pass butt welded joints in thick HSLA-100 steel plates was evaluated. The grain size was related with the temporal history of the location, which was obtained using an existing thermal model based on Gaussian heat source distribution for two different heat-input conditions. For a heat-input of 10 kJ/cm the grain size in the coarse grain heat-Affected Zone was 80 μm corresponding to a peak temperature of 1450 °C, but falls sharply to 40 μm within a distance of 0.5 mm from the fusion line. At a higher heat-input of 40 kJ/cm the grain size is 130 μm for the same peak temperature and the coarse grain heat-Affected Zone is 1.1 mm wide. The austenite grain size significantly influences the microstructure and properties of the heat-Affected Zone.
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precipitate dissolution and grain growth in the heat Affected Zone of hsla 100 steel
Isij International, 2003Co-Authors: Mahadev Shome, D S Sarma, O P Gupta, O N MohantyAbstract:An attempt has been made to predict the dissolution of Nb(CN) precipitates in the heat Affected Zone (HAZ) of a Nb containing HSLA-100 steel. An invariant size approximation model along with existing solubility product data have been applied to continuous heating and cooling situation to ascertain the kinetic strengths from heat input-peak temperature conditions at which dissolution of precipitates take place. Peak temperatures beyond which precipitates rapidly dissolve and cause grain growth have been identified, and they are in consonance with the austenite grain growth data.
S Genna - One of the best experts on this subject based on the ideXlab platform.
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heat Affected Zone extension in pulsed nd yag laser cutting of cfrp
Composites Part B-engineering, 2018Co-Authors: Claudio Leone, S GennaAbstract:Abstract Laser cutting is a promising alternative to the traditional methods in CFRP cutting. However, laser cutting is based on thermal interaction that results in thermal damages of both matrix and fibres. The heat Affected Zone (HAZ) extension is strictly dependent on the adopted laser source and the working parameters. The paper presents an experimental study on the laser cutting of CFRP plate, 1 mm in thickness by means of 150 W Nd:YAG pulsed laser. The cutting region and the influence of process parameters, pulse energy, pulse duration and overlapping, on the kerf geometry and the HAZ were analyzed. Experimental results showed that the adopted laser is able to cut the CFRP plate, up to 10.8 mm/s. However, an accurate selection of the process parameters is necessary in order to obtain the maximum cutting speed and a narrow HAZ. Moreover, a relation between the HAZ extension and the process parameters (average power, cutting speed, pulse frequency and pulse duration) was found.
S Moeinifar - One of the best experts on this subject based on the ideXlab platform.
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role of tandem submerged arc welding thermal cycles on properties of the heat Affected Zone in x80 microalloyed pipe line steel
Journal of Materials Processing Technology, 2011Co-Authors: S Moeinifar, A H Kokabi, H Madaah R HosseiniAbstract:Abstract The influence of thermal cycles on the properties of the coarse grained heat Affected Zone in X80 microalloyed steel has been investigated. The thermal simulated involved heating the X80 steel specimens to the peak temperature of 1400 °C, with different cooling rates. The four-wire tandem submerged arc welding process, with different heat input values, was used to generate a welded microstructure. The martensite/austenite constituent appeared in the microstructure of the heat Affected Zone region for all the specimens along the prior-austenite grain boundaries and between the bainitic ferrite laths. The blocky-like and stringer martensite/austenite morphology were observed in the heat Affected Zone region. The fractional area of M/A particles due to different cooling rate was the main factor in increasing of the hardness values in the coarse grained heat Affected Zone. The Charpy absorbed energy of specimens was assessed using Charpy impact testing at −50 °C. The martensite/austenite constituent's size such as mean diameter and length are important factors influencing Charpy impact properties of coarse grained heat Affected Zone. The micro crack nucleation may occur from M/A particles at the intersection of prior-austenite grain boundaries. Similar crack initiation sites and growth mechanism were investigated for specimens welded with different heat input values.
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influence of four wires tandem submerged arc welding process on heat Affected Zone properties in high strength pipeline steel
2010Co-Authors: S Moeinifar, A H Kokabi, Hamid Reza Madaah Hosseini, Chengjia J Shang, Gou Hui, Liu Zhen WeiAbstract:The objective of this investigation was to provide a detailed evaluation of the heat Affected Zone properties of a high-strength pipeline steel. The X80 high-strength low-alloy microalloyed steel was supplied as a hot rolled plate with accelerated cooling. The four-wire tandem submerged arc welding process with different heat input was used to generate welded joints. The microstructure of the heat Affected Zone depended on heat input values. M/A constituent appeared in the microstructure of HAZ region for all of the specimens along the prior-austenite grain boundaries and between bainitic ferrite laths. Charpy impact specimens were notched in four locations: FL (fusion line), FL+1mm, FL+2mm and FL+3mm. The Charpy absorbed energy of specimens was assessed using Charpy impact testing at -50°C.