Three Dimensional Prediction of Microstructure Evolution and Mechanical Properties of Hot Strips

2011 ◽  
Vol 291-294 ◽  
pp. 455-464 ◽  
Author(s):  
Guo Ming Zhu ◽  
Chao Lv ◽  
Yong Lin Kang ◽  
Guo Guang Cheng

With the 3D thermal mechanical coupled elastic-plastic finite element method and by simulating the whole rolling process of 1250mm×20mm C-Mn hot strips, this paper obtains the temperature field and deformation result of the rolling process. By comparing the temperature drop curve with the measured data in the field, it shows that the simulation result is close to the real situation. Based on the thermal mechanical coupled simulation of the whole rolling process, this paper completes the computational simulation of the prediction of the 3D microstructure and property of hot strips by using the relevant microstructure evolution and property prediction models and advanced C language programming, thus providing reference for the property prediction of new products and processes.

2018 ◽  
Vol 930 ◽  
pp. 305-310
Author(s):  
André Luiz Moraes Alves ◽  
Guilherme Dias da Fonseca ◽  
Marcos Felipe Braga da Costa ◽  
Weslley Luiz da Silva Assis ◽  
Paulo Rangel Rios

In the phase transformations of the solid state, situations can occur in which the initial phase transform forming two or more distinct phases. The exact mathematical model for situations where more than one transformation occurs simultaneously or sequentially was proposed by Rios and Villa. The computational simulation was used to study the evolution and visualization of the possible microstructures that these transformations may present. The causal cone methodology was adopted. The simulations were compared with the analytical model to ensure that they occur as expected. The growth of individual grains of each phase was monitored in 3D microstructure evolution. With this monitoring, was possible to extract useful data able to quantify the simulated 3D microstructure. Quantifying the simulated microstructures increase the possibility of the simulations give to the experimentalist insights about the transformations. In this paper, it is verified that each grain evolves in an individual way, as expected, however their growth is similar.


Author(s):  
Chung-Hyun Goh ◽  
Salman Ahmed ◽  
Adam P. Dachowicz ◽  
Janet K. Allen ◽  
Farrokh Mistree

A transmission gear is generally produced by a sequence of several processes from steelmaking to final machining and surface treatment. The intermediate processes such as hot rolling induce microstructure evolution and phase transformation which play a significant role in determining the mechanical properties and fatigue strength of gears. Therefore, these intermediate processes should be carefully considered in determining the performance and properties of the end product. In this paper, an integrated multiscale robust design approach using the Inductive Design Exploration Method (IDEM) is implemented to improve robustness in the presence of uncertainty by exploring the solution space in order to find feasible solutions to satisfy technical requirements and/or customer aspirations. Four pass roll design with oval and round grooves is used to simulate the hot bar rolling process. The microstructure evolution, flow stress, and wear prediction models are implemented in the analysis model to account for the process-structure relationship in each roll pass. Surrogate models for some parameters such as ultimate tensile strength are then developed based on the analysis results. Using the relationship of processing-structure-property-performance, the integrated realization of engineered materials and products (IREMP) can be accomplished over multiple length scales. In IDEM, the range of the property-performance relationship is first evaluated by the requirements for the end product. Subsequently, the austenite and ferrite grain sizes and material properties are inductively determined by exploring the design space. Consequently roll pass design including the rolling conditions and the microstructure of billets are customized by the exploration of design variables based on IDEM.


Author(s):  
Bowen Chen ◽  
Qi Ding ◽  
Dewei Ni ◽  
Hongda Wang ◽  
Yusheng Ding ◽  
...  

AbstractIn this work, three-dimensional (3D) Cf/SiBCN composites were fabricated by polymer infiltration and pyrolysis (PIP) with poly(methylvinyl)borosilazane as SiBCN precursor. The 3D microstructure evolution process of the composites was investigated by an advanced X-ray computed tomography (XCT). The effect of dicumyl peroxide (DCP) initiator addition on the crosslinking process, microstructure evolution, and mechanical properties of the composites were uncovered. With the addition of a DCP initiator, the liquid precursor can cross-linking to solid-state at 120 °C. Moreover, DCP addition decreases the release of small molecule gas during pyrolysis, leading to an improved ceramic yield 4.67 times higher than that without DCP addition. After 7 PIP cycles, density and open porosity of the final Cf/SiBCN composite with DCP addition are 1.73 g·cm−3 and ∼10%, respectively, which are 143.0% higher and 30.3% lower compared with the composites without DCP addition. As a result, the flexural strength and elastic modulus of Cf/SiBCN composites with DCP addition (371 MPa and 31 GPa) are 1.74 and 1.60 times higher than that without DCP addition (213 MPa and 19.4 GPa), respectively.


2012 ◽  
Vol 268-270 ◽  
pp. 297-300
Author(s):  
Qing Qiang He ◽  
Jia Sun ◽  
Jun You Zhao ◽  
Li Jian Xu ◽  
Cui Cui Li

In hot metal forming processes, the material is subjected to the thermo-mechanical processing. A fully three dimensional thermo-mechanically coupled FEM-simulation of an eleven pass hot rough rolling process of H-beam has been performed. Microstructure evolution equations available in literatures were incorporated into the commercial FE solver ABAQUS/Explicit, through user defined subroutine VUMAT, to simulate the microstructure evolution. Since it’s impractical to obtain the austenite grain size distribution in the beam blank during industrial hot rolling, the calculated rolling loads are compared with the mills loads instead of grain size comparison between the predicted average value and the real ones.


Author(s):  
Neil Rowlands ◽  
Jeff Price ◽  
Michael Kersker ◽  
Seichi Suzuki ◽  
Steve Young ◽  
...  

Three-dimensional (3D) microstructure visualization on the electron microscope requires that the sample be tilted to different positions to collect a series of projections. This tilting should be performed rapidly for on-line stereo viewing and precisely for off-line tomographic reconstruction. Usually a projection series is collected using mechanical stage tilt alone. The stereo pairs must be viewed off-line and the 60 to 120 tomographic projections must be aligned with fiduciary markers or digital correlation methods. The delay in viewing stereo pairs and the alignment problems in tomographic reconstruction could be eliminated or improved by tilting the beam if such tilt could be accomplished without image translation.A microscope capable of beam tilt with simultaneous image shift to eliminate tilt-induced translation has been investigated for 3D imaging of thick (1 μm) biologic specimens. By tilting the beam above and through the specimen and bringing it back below the specimen, a brightfield image with a projection angle corresponding to the beam tilt angle can be recorded (Fig. 1a).


Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 569
Author(s):  
Ana Claudia González-Castillo ◽  
José de Jesús Cruz-Rivera ◽  
Mitsuo Osvaldo Ramos-Azpeitia ◽  
Pedro Garnica-González ◽  
Carlos Gamaliel Garay-Reyes ◽  
...  

Computational simulation has become more important in the design of thermomechanical processing since it allows the optimization of associated parameters such as temperature, stresses, strains and phase transformations. This work presents the results of the three-dimensional Finite Element Method (FEM) simulation of the hot rolling process of a medium Mn steel using DEFORM-3D software. Temperature and effective strain distribution in the surface and center of the sheet were analyzed for different rolling passes; also the change in damage factor was evaluated. According to the hot rolling simulation results, experimental hot rolling parameters were established in order to obtain the desired microstructure avoiding the presence of ferrite precipitation during the process. The microstructural characterization of the hot rolled steel was carried out using optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that the phases present in the steel after hot rolling are austenite and α′-martensite. Additionally, to understand the mechanical behavior, tensile tests were performed and concluded that this new steel can be catalogued in the third automotive generation.


Author(s):  
Jiehai Zhang ◽  
Arun Muley ◽  
Joseph B. Borghese ◽  
Raj M. Manglik

Enhanced heat transfer characteristics of low Reynolds number airflows in three-dimensional sinusoidal wavy plate-fin channels are investigated. For the computational simulation, steady state, constant property, periodically developed, laminar forced convection is considered with the channel surface at the uniform heat flux condition; the wavy-fin is modeled by its two asymptotic limits of 100% and zero fin efficiency. The governing equations are solved numerically using finite-volume techniques for a non-orthogonal, non-staggered grid. Computational results for velocity and temperature distribution, isothermal Fanning friction factor f and Colburn factor j are presented for airflow rates in the range of 10 ≤ Re ≤ 1500. The numerical results are further compared with experimental data, with excellent agreement, for two different wavy-fin geometries. The influence of fin density on the flow behavior and the enhanced convection heat transfer are highlighted. Depending on the flow rate, a complex flow structure is observed, which is characterized by the generation, spatial growth and dissipation of vortices in the trough region of the wavy channel. The thermal boundary layers on the fin surface are periodically disrupted, resulting in high local heat fluxes. The overall heat transfer performance is improved considerably, compared to the straight channel with the same cross-section, with a relatively smaller increase in the associated pressure drop penalty.


2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Ying Yan ◽  
Gengping Li ◽  
Jinjun Tang ◽  
Zhongyin Guo

Operating speed is a critical indicator for road alignment consistency design and safety evaluation. Although extensive studies have been conducted on operating speed prediction, few models can finish practical continuous prediction at each point along alignment on multilane highways. This study proposes a novel method to estimate the operating speed for multilane highways in China from the aspect of the three-dimensional alignment combination. Operating speed data collected in field experiments on 304 different alignment combination sections are detected by means of Global Positioning System. First, the alignment comprehensive index (ACI) is designed and introduced to describe the function accounting for alignment continuity and driving safety. The variables used in ACI include horizontal curve radius, change rate of curvature, deflection angle of curve, grade, and lane width. Second, the influence range of front and rear alignment on speed is determined on the basis of drivers’ fixation range and dynamical properties of vehicles. Furthermore, a prediction model based on exponential relationships between road alignment and speeds is designed to predict the speed of passenger cars and trucks. Finally, three common criteria are utilized to evaluate the effectiveness of the prediction models. The results indicate that the prediction models outperform the other two operating speed models for their higher prediction accuracy.


1994 ◽  
Vol 361 ◽  
Author(s):  
V.A. Alyoshin ◽  
E.V. Sviridov ◽  
V.I.M. Hukhortov ◽  
I.H. Zakharchenko ◽  
V.P. Dudkevich

ABSTRACTSurface and cross-section relief evolution of ferroelectric epitaxial (Ba,Sr)TiO3 films rf-sputtered on (001) HgO crystal cle-avage surface versus the oxygen worKing gas pressure P and subst-rate temperature T were studied. Specific features of both three-dimensional and two-dimensional epitaxy mechanisms corresponding to various deposition conditions were revealed. Difference between low and high P-T-value 3D epitaxy was established. The deposition of films with mirror-smooth surfaces and perfect interfaces is shown to be possible.


2014 ◽  
Vol 687-691 ◽  
pp. 3-6
Author(s):  
Da Ming Wang ◽  
Ming Zhe Li ◽  
Zhong Yi Cai

3D rolling is a novel technology for three-dimensional surface parts. In this process, by controlling the gap between the upper and lower forming rolls, the sheet metal is non-uniformly thinned in thickness direction, and the longitudinal elongation of the sheet metal is different along the transverse direction, which makes the sheet metal generate three-dimensional deformation. In this paper, the transition zones of spherical surface parts in 3D rolling process are investigated. Spherical surface parts with the same widths but different lengths are simulated in condition of the same roll gap, and their experimental results are presented. The forming precision of forming parts and the causes of transition zones in the head and tail regions are analyzed through simulated results. The simulated and experimental results show that the lengths of transition zones of spherical surfaces in the head and tail regions are fixed values in condition of the same sheet width and roll gap.


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