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Bakri Abdulhay - One of the best experts on this subject based on the ideXlab platform.

  • Latent Heat Estimation of the Martensite Transformation Through Inverse Methods During the Hot Stamping Process
    Volume 2: Applied Fluid Mechanics; Electromechanical Systems and Mechatronics; Advanced Energy Systems; Thermal Engineering; Human Factors and Cogniti, 2012
    Co-Authors: Alexandre Blaise, Bakri Abdulhay, Brahim Bourouga, Christine Dessain
    Abstract:

    In the Hot Stamping Process, the temperature evolution drives the metallurgy, as well as the metallurgical transformation influences the temperature evolution through the exothermic nature of the austenite to martensite transformation. This heat release has already been highlighted by previous experimental work. This heat release leads to a source term in the heat equation in the blank. This source term must be quantified in order to accurately predict blank temperature evolution. Moreover, the end of the heat release corresponds to the end of the metallurgical transformation. It allows the determination of the minimum quenching time, relevant information for industry to minimize the Process time.This paper presents a method to quantify the heat released by the metallurgical transformation during the Hot Stamping of Usibor 1500P® ArcelorMittal steel, solving inverse conduction problems. It allows the determination of this heat release as a function of temperature or time. Then, integrating it, the latent heat of the transformation can be estimated. This can be done for different contact pressures between tool and blank. Finally, it can be linked to the martensite proportion to estimate it as a function of time or temperature and determine the Koistinen-Marburger model parameters. These results should improve the accuracy of numerical simulations of the Hot Stamping Process.Copyright © 2012 by ASME

  • experimental and theoretical study of thermal aspects of the Hot Stamping Process
    Applied Thermal Engineering, 2011
    Co-Authors: Bakri Abdulhay, Brahim Bourouga, Christine Dessain
    Abstract:

    Abstract The objective of the present article is the thermal conductance estimation to improve the Usibor 1500P ® blank cooling during the Hot Stamping Process. An experimental device was designed and developed to estimate the thermal contact resistance at the part/tool interface. The designed Stamping tool is composed of a die and a punch made in Z160CDV12 steel and presenting an omega shape. Samples and tools are thermally instrumented with thermocouples type K sheathed with silky glass, forming heat-flux meters in the most interesting locations in the tools. Reproducibility tests showed a good repeatability of recorded and estimated parameters with a mean dispersion less than 5%; it was noticed that a re-heating of the cooled part due to its microstructure transformation occurring systematically at 400 °C. At the surface boundary of the part, thermal conductances are calculated using convective/radiation modeling of both phases: approach and forming. At the contact interfaces, thermal contact resistances R C are estimated experimentally through a non-linear 1D inverse technique founded on sequential method of Beck. Results have been established as correlation of type: R C  =  f ( P ) to be used for numerical simulation.

  • experimental study of heat transfer in Hot Stamping Process
    International Journal of Material Forming, 2009
    Co-Authors: Brahim Bourouga, Bakri Abdulhay, Christine Dessain, Gilles Brun, Joël Wilsius
    Abstract:

    Hot Stamping and quenching of boron steel is a novel technology to produce structural automotive parts with an excellent crash performance. It offers the opportunity to produce thinner parts with complex shapes and higher mechanical properties. In order to increase the simulation expertise of the Hot Stamping Process,, an experimental device has been designed and developed to accurately measure the thermal contact resistance (TCR) under representative Process conditions. This parameter characterizes the heat transfer intensity between the tools made in Z160 steel and Usibor 1500P blank (a precoated carbon/manganese steel) at the contact interface. In this paper, we present an approach to determine experimentally the evolution of the TCR under different contact pressure (2 to 30 MPa).

Wolfgang Bleck - One of the best experts on this subject based on the ideXlab platform.

  • phase transformations in a simulated Hot Stamping Process of the boron bearing steel
    Materials & Design, 2015
    Co-Authors: M Nikravesh, M Naderi, G H Akbari, Wolfgang Bleck
    Abstract:

    Abstract A Hot Stamping Process was experimentally simulated by a Hot deformation dilatometer to investigate phase transformations and final properties of 22MnB5 boron\bearing steel. For this purpose, the phase fraction in the microstructure of boron bearing steel with and without Hot deformation was evaluated. The results showed that mechanical stabilization of austenite during the deformation Process led to decreased amount of military phases while bainite and reconstructive transformations, especially ferrite were promoted. But, when there was no martensite in the final microstructure, the effect of deformation on ferrite formation was negligible. Also, due to deformation, total hardness was decreased in cooling rates of higher than 6 °C/s. But, on the contrary, in cooling rates of lower than 6 °C/s, remarkably reverse results were achieved. Finally, the CCT and DCCT diagrams of elaborated steel were constructed.

  • An Investigation Into MartensiticTransformation In Hot Stamping Process
    WIT transactions on engineering sciences, 2007
    Co-Authors: M Naderi, Wolfgang Bleck
    Abstract:

    The main target of the Hot Stamping Process is to get fully martensitic microstructure in the end product. In the current study, the Hot Stamping Process is simulated by the simultaneous forming and quenching experiments. This is done through uniaxial compression tests at high temperatures by a dilatometry machine. The effects of Process parameters like strain, strain rate, initial deformation temperature and austenization soaking time and mainly the applied force, on martensitic transformation of the ultra high strength boron steel are investigated. Besides, the presence of other phases like bainite and ferrite and their effects on martensitic transformation is considered. It is concluded that by increasing strain rate and initial deformation temperature, martensite content, hardness and martensite start temperature (Ms) are increased. On the contrary, by applying higher deformations, the above mentioned properties are decreased. It is also concluded that, regardless of the Process parameters, higher applied forces deteriorate the successful martensitic transformation during the Hot Stamping Process.

M Naderi - One of the best experts on this subject based on the ideXlab platform.

  • phase transformations in a simulated Hot Stamping Process of the boron bearing steel
    Materials & Design, 2015
    Co-Authors: M Nikravesh, M Naderi, G H Akbari, Wolfgang Bleck
    Abstract:

    Abstract A Hot Stamping Process was experimentally simulated by a Hot deformation dilatometer to investigate phase transformations and final properties of 22MnB5 boron\bearing steel. For this purpose, the phase fraction in the microstructure of boron bearing steel with and without Hot deformation was evaluated. The results showed that mechanical stabilization of austenite during the deformation Process led to decreased amount of military phases while bainite and reconstructive transformations, especially ferrite were promoted. But, when there was no martensite in the final microstructure, the effect of deformation on ferrite formation was negligible. Also, due to deformation, total hardness was decreased in cooling rates of higher than 6 °C/s. But, on the contrary, in cooling rates of lower than 6 °C/s, remarkably reverse results were achieved. Finally, the CCT and DCCT diagrams of elaborated steel were constructed.

  • Semi-Hot Stamping as an Improved Process of Hot Stamping
    Journal of Materials Science & Technology, 2011
    Co-Authors: M Naderi, M Abbasi, Mostafa Ketabchi, Wolfgang Bleak
    Abstract:

    Reducing the forming load, deletion of springback, increasing the formability of sheets as well as producing high strength parts are the main reasons to apply Hot Stamping Process. Hot Stamping Process and 22MnB5 steels are the state of the art Process and grades, respectively; however novel Processes and steel grades are under considerations. In the current research, behavior of the steel grade MSW1200 blanks under semi and fully Hot Stamping Processes was characterized. During semi-Hot Stamping Process, the blank was firstly heated to a temperature of about 650°C and then formed and quenched in the die assembly, simultaneously. Microstructure and mechanical properties of semi and fully Hot stamped blanks were studied and the results were compared with those of normally water/air quenched blanks. The Hot stamped blanks attained the strength values as high as water quenched blanks. The highest ductility and consequently, the best formability were achieved for the blank which had been semi-Hot stamped. It was concluded that for the mentioned steel, semi-Hot Stamping Process could be considered as an improved thermo-mechanical Process which not only guaranteed a high formability, but also led to ultra high strength values.

  • An Investigation Into MartensiticTransformation In Hot Stamping Process
    WIT transactions on engineering sciences, 2007
    Co-Authors: M Naderi, Wolfgang Bleck
    Abstract:

    The main target of the Hot Stamping Process is to get fully martensitic microstructure in the end product. In the current study, the Hot Stamping Process is simulated by the simultaneous forming and quenching experiments. This is done through uniaxial compression tests at high temperatures by a dilatometry machine. The effects of Process parameters like strain, strain rate, initial deformation temperature and austenization soaking time and mainly the applied force, on martensitic transformation of the ultra high strength boron steel are investigated. Besides, the presence of other phases like bainite and ferrite and their effects on martensitic transformation is considered. It is concluded that by increasing strain rate and initial deformation temperature, martensite content, hardness and martensite start temperature (Ms) are increased. On the contrary, by applying higher deformations, the above mentioned properties are decreased. It is also concluded that, regardless of the Process parameters, higher applied forces deteriorate the successful martensitic transformation during the Hot Stamping Process.

Yi Sheng Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Investigation on Contact Heating of Aluminum Alloy Sheets in Hot Stamping Process
    Metals, 2019
    Co-Authors: Huicheng Geng, Yi Lin Wang, Zijian Wang, Yi Sheng Zhang
    Abstract:

    Application of the Hot Stamping Process on heat-treatable aluminum alloys effectively solves the problems of large springback and poor ductility during forming at room temperature, which expands the range of applications of aluminum alloys in the transportation industry. Sheet heating plays an important role in the Hot Stamping Process, and increasing the heating rate can improve the Hot Stamping efficiency to some extent. In this paper, the feasibility of applying contact heating techniques with higher heating rates in the Hot Stamping Process was studied. A contact heating device was designed, and the temperature distribution of the device contact surface was observed. Furthermore, the heating characteristics of 7075 aluminum alloy sheets during the contact heating Process were explored by experiments and finite element simulation. Finally, the rapid solution treatment of aluminum alloy was carried out with a contact heating device, which was compared with the furnace heating solution treatment. The experimental and simulation results indicate that the device contact surface has a relatively uniform temperature distribution, and the aluminum alloy sheets can be heated to close to the set temperature in 15 s using contact heating techniques. Meanwhile, the rapid solution treatment of aluminum alloy sheets can be achieved within 15–20 s by contact heating techniques, obtaining superior mechanical properties. This suggests that the contact heating Process can be used for rapid heating and rapid solution treatment of aluminum alloy sheets in Hot Stamping Process.

  • Modeling of Hot Stamping Process procedure based on finite state machine (FSM)
    The International Journal of Advanced Manufacturing Technology, 2017
    Co-Authors: Liang Wang, Qiang Wang, Yi Sheng Zhang
    Abstract:

    Hot Stamping technology of high strength steel creates new possibilities for vehicle manufacturers in promoting safety and fuel efficiency. The proportion of Hot Stamping parts in vehicles increases each year, and there are already hundreds of different types of Hot Stamping lines throughout the world. However, few studies regarding modeling of Hot Stamping Process procedure have been reported, nor have there been studies regarding cooperative scheduling of manufacturing units (including heating units, transferring units, and forming units), or the relationship between productivity and energy consumption. With the shortening of the vehicle life cycle, auto parts manufacturing must be flexible for multiple types and small batches to meet the challenges of the market. In this paper, a model of the Hot Stamping Process procedure based on finite state machine is established, then the model is adapted for the procedure control of a Hot Stamping line, consisting of multi-chamber furnaces, linear conveying robots, and a mechanical servo press. The cooperative scheduling of various manufacturing units, especially the method which matches multiple heating chambers with a single forming die, is focused on. Finally, a Hot Stamping line with multi-chamber furnaces is designed and implemented, and the analysis of its production sequence, energy consumption, and delivery cycles is performed. The results show that with the new modeling method of Hot Stamping Process based on finite state machine, the new developed Hot Stamping line is capable of multiple production objectives and flexible configuration in accordance with production and delivery periods. This active configuration aids in extending equipment life and reduce energy consumption. The modeling method expands production models for Hot Stamping, from the mass production model to multiple types and small batches production model.

  • Research on equipments and production line of Hot Stamping
    Proceedings of the 5th International Conference on Advanced Design and Manufacturing Engineering, 2015
    Co-Authors: Liang Wang, Yi Sheng Zhang
    Abstract:

    transportation; Abstract. Hot Stamping is a reliable way for the production of high performance auto parts with light weight. Hot Stamping Process requires pre-blanking steel sheet to be transported and Processed at elevated temperature, and the performance of Hot Stamping products is closely related to temperature. This paper presents 2 types of Hot Stamping lines independently developed, 2000kN test line and 6000kN production line. The 2000kN test line is composed of a chamber furnace for heating blanks, a 2000kN electric servo mechanical press for forming heated blanks and a joint robot for transporting. The production line has multi-chamber furnaces, high-speed multi-axis Cartesian robots and electric servo mechanical press. Hot Stamping Process is carried out by heating equipments, transporting equipments and forming equipments cooperatively. Mechanical link servo press (MLSP) carries out Hot Stamping Process by fast downward, slowly mold closing and holding pressure at bottom. Robots cooperatively transport Hot blanks as fast as possible for the sake of reducing exposure at air and temperature drop. Multi-chamber furnaces dispatch chambers into or out of production cycle to implement flexible production. The production line carries out continuous and efficient production at a steady beat.

  • A New Hot Stamping Process with Quenching and Partitioning Treatment
    Advanced Materials Research, 2015
    Co-Authors: Xiang Yun Yu, Jian Li, Kai Wang, Yi Sheng Zhang
    Abstract:

    A new Hot Stamping Process with quenching and partitioning treatment is proposed in the paper. Compared to direct Hot Stamping Process, the microstructures with some retained austenite not only including martensite are formed according to the constrained carbon equilibrium (CCE) model. During the new Hot Stamping Process, tools with high temperature are used to control the quenching temperature (QT) between Ms and Mf, and the partitioning treatment of the part is also implemented in the tools by prolonging holding times. In this paper, different holding times (partitioning times) controlled by servo press, are used to research the influence of partitioning time on mechanical properties.

  • A New Hot Stamping Process with Quenching and Partitioning Treatment
    Advanced Materials Research, 2015
    Co-Authors: Xiang Yun Yu, Jian Li, Kai Wang, Yi Sheng Zhang
    Abstract:

    A new Hot Stamping Process with quenching and partitioning treatment is proposed in the paper. Compared to direct Hot Stamping Process, the microstructures with some retained austenite not only including martensite are formed according to the constrained carbon equilibrium (CCE) model. During the new Hot Stamping Process, tools with high temperature are used to control the quenching temperature (QT) between Ms and Mf, and the partitioning treatment of the part is also implemented in the tools by prolonging holding times. In this paper, different holding times (partitioning times) controlled by servo press, are used to research the influence of partitioning time on mechanical properties.

Jun Chen - One of the best experts on this subject based on the ideXlab platform.

  • Investigation of the Hot Stamping Process for TRIP Steel with High Strength and High Ductility
    Journal of Materials Engineering and Performance, 2019
    Co-Authors: Xianhong Han, Huizhen Zhang, Johnston Jackie Tang, Cheng-long Wang, Jun Chen
    Abstract:

    In order to obtain the products with high strength and ductility, the Hot Stamping technology of TRIP steel has been getting more attention in recent years. In this study, the effects of cooling rate on the mechanical properties of a typical TRIP780 steel used in Hot Stamping Process were investigated with tensile tests, bending tests and impact tests. It was found that even though a lower cooling rate for the quenching of TRIP780 steel led to the formation of the bainite and ferrite mixture phases, the mechanical properties of the material containing these phases were similar to those of the material containing martensite only. TRIP780 steel exhibited twice the elongation with a similarly high strength as compared with the conventional boron steel, and its mechanical properties are insensitive to cooling rate, which was approved by the Hot Stamping experiment of a U-cap part.

  • Research on Q&P Hot Stamping Process integrated with fractional cooling strategy
    Procedia Engineering, 2017
    Co-Authors: Xianhong Han, Sisi Chen, Shulin Tan, Yanan Ding, Jun Chen
    Abstract:

    Abstract Hot Stamping technology has been widely used to produce high strength steel parts, but the elongation of the production is limited which leads to low ductility. In this paper, the quenching & partitioning treatment (Q&P) has been introduced into the existed Hot Stamping Process to develop the Q&P Hot Stamping technology. Moreover, a fractional cooling strategy was also introduced, which improves the formability and helps to reduce the cooling requirement of the tool as well. By the presented Process, the specimen was firstly quenched quickly to a suitable forming temperature by water spray method, then it was stamped and quenched inside the tool, and subsequently partitioned and secondly quenched to room temperature. The presented Process can improve the elongation effectively and maintain the strength in a high level, which was proved by a series of Gleeble tests and real forming tests. OM and SEM observations were also provided to study the mechanisms of the Process.

  • Research on one-step quenching and partitioning treatment and its application in Hot Stamping Process:
    Proceedings of the Institution of Mechanical Engineers Part B: Journal of Engineering Manufacture, 2015
    Co-Authors: Xianhong Han, Yaoyao Zhong, Pensen Xin, Zhenshan Cui, Jun Chen
    Abstract:

    Hot Stamping Process has been regarded as one of the most attractive Processes to produce high-strength parts with merits of low-forming load and small springback. However, the elongation of the Hot-stamped parts is small, so the ability of crash resistance is limited. Recently, a novel Hot Stamping Process integrated with quenching and partitioning treatment has been presented to improve the elongation of the final parts. In this article, the quenching and partitioning Hot Stamping Process is further studied using the boron steel B1500HS, and the feasibility is verified by a series of quenching and partitioning tests followed by mechanical tests and microstructure observations. Moreover, an experimental tool for quenching and partitioning Hot Stamping Process is first proposed in this article, where both air cooling device and heating system are designed, and a U-channel part is produced. Finally, in order to illustrate the active role of high elongation that the quenching and partitioning Hot Stamping p...

  • Application of Hot Stamping Process by Integrating Quenching & Partitioning Heat Treatment to Improve Mechanical Properties
    Procedia Engineering, 2014
    Co-Authors: Xianhong Han, Yaoyao Zhong, Zhenshan Cui, Kun Yang, Jun Chen
    Abstract:

    Abstract In order to improve the ductility of Hot Stamping products, the quenching & partitioning heat treatment is integrated into the traditional Hot Stamping Process. The feasibility of the new Process is investigated by both thermal simulation through Gleeble 3500 system and Hot Stamping experiments with a special experimental tool firstly introduced. The microstructure observations show that the new Process induces dual-phase microstructures of martensite and residual austenite for the final part, which improves the elongation effectively and maintains the high-strength at the same time. The product of tensile strength and plasticity of the test material B1500HS based on the presented quenching & partitioning Process with appropriate Process parameters is 24% larger than that of the traditional Hot Stamping.

  • application of Hot Stamping Process by integrating quenching partitioning heat treatment to improve mechanical properties
    Procedia Engineering, 2014
    Co-Authors: Xianhong Han, Yaoyao Zhong, Zhenshan Cui, Kun Yang, Jun Chen
    Abstract:

    Abstract In order to improve the ductility of Hot Stamping products, the quenching & partitioning heat treatment is integrated into the traditional Hot Stamping Process. The feasibility of the new Process is investigated by both thermal simulation through Gleeble 3500 system and Hot Stamping experiments with a special experimental tool firstly introduced. The microstructure observations show that the new Process induces dual-phase microstructures of martensite and residual austenite for the final part, which improves the elongation effectively and maintains the high-strength at the same time. The product of tensile strength and plasticity of the test material B1500HS based on the presented quenching & partitioning Process with appropriate Process parameters is 24% larger than that of the traditional Hot Stamping.