scholarly journals Hardness Prediction in Hot Stamping Process by Local Blank Heating Based on Quench Factor Analysis

Metals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 29
Author(s):  
Jae-Hong Kim ◽  
Dae-Cheol Ko ◽  
Seon-Bong Lee ◽  
Byung-Min Kim

Recently, the hot stamping process using local blank heating has been widely used to manufacture lightweight and crashworthy automotive parts. However, the hardness prediction of hot stamped parts produced using local blank heating is difficult because it involves many process variables, such as the heating temperature, heating time, and cooling rate. The purpose of this study was to predict the hardness of hot stamped parts fabricated using local blank heating based on quench factor analysis (QFA). The volume fraction of austenite was measured to consider the phase transformation in the heating stage, and it was expressed by the Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation. Additionally, a dilatometry test was performed to measure the hardness according to the cooling rates, which was used to determine the material constants for QFA. Finite-element simulation was performed to predict the temperature histories during the hot stamping process and the results were used to predict the hardness according to QFA with the JMAK equation. A hot stamping experiment with local blank heating equipment was performed, and the predicted and experimental results were compared for verification of the proposed hardness prediction method.

2008 ◽  
Vol 575-578 ◽  
pp. 299-304 ◽  
Author(s):  
Jun Bao ◽  
Zhong Wen Xing ◽  
Yu Ying Yang

The quenchable boron steel is a novel type of ultra high strength steel used for automotive parts so as to reduce the weight of the whole automobile. The hot stamping processing experiments for bending parts were studied. The influence of the hot stamping processing parameters, such as the heating temperature, the heat holding time and the cooling water flow velocity, on the mechanics properties and microstructure of the hot stamping parts is obtained. And then the optimal ranges of these parameters are determined, which provides a basis for the control of the hot stamping process applied in complicated shape parts’ production.


Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 50
Author(s):  
Jae-Hong Kim ◽  
Seon-Bong Lee ◽  
Byung-Min Kim

Recently, in order to improve crashworthiness and achieve weight reduction of car body, a hot stamping process has been applied to the production of the part with tailored properties using tailored tool thermomechanical treatment. In the tailored tool thermomechanical treatment process, process parameters influence the mechanical properties of final product such as strength and hardness. Therefore, the prediction of hardness for final product is very important to manufacture hot-stamped part considering various process parameters. The purpose of this study is to propose a process window, which can predict hardness for various process parameters in tailored tool thermomechanical treatment. To determine the process window, finite element (FE) simulation coupled with quench factor analysis (QFA) has been performed for combinations of various process parameters. Subsequently, the process window was constructed through the training of artificial neural network (ANN) and experiment of tailored tool thermomechanical treatment for hat-shaped part was performed to verify effectiveness of hardness prediction. Then, the process parameters were determined from process window for hot stamping of the hat-shaped part with the required distribution of hardness. Hardness predicted by process window was in good agreement with measured one within 3.1% error in additional experiment. Therefore, the suggested process window can be used efficiently for hardness prediction and determination of process parameters in tailored tool thermomechanical treatment of hot-stamping parts.


2006 ◽  
Author(s):  
Lauralice C. Franceschini Canale ◽  
Antônio Carlos Canale ◽  
Charles E. Bates ◽  
George E. Totten

2014 ◽  
Vol 1063 ◽  
pp. 108-111
Author(s):  
Ping Li ◽  
Yu Sheng Liu ◽  
Tian Zong Gongzi ◽  
Ke Min Xue

The hot stamping process of ultra high strength steel(UHSS) sheet is an innovative way to manufacture the components with a ultra high tensile strength. The sufficiency of martensitic transformation in formed component is affected by pre-heating temperature of blank directly. In this paper, experiments of heating UHSS blanks to 700°C, 800°C, 900°C and 1000°C were implemented to investigate the effect of pre-heating temperature on the formed component’s microstructure and mechanical properties. The results indicate that 900°C is the best pre-heating temperature for hot stamping process. The microstructure of formed component is all fine and uniform martensite. Meanwhile, tensile strength and vickers hardness raise up to 1580MPa and 450HV, respectively.


Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 842
Author(s):  
Wenming Jin ◽  
Jianhao Yu ◽  
Zhiqiang Zhang ◽  
Hongjie Jia ◽  
Mingwen Ren

Contact solution treatment (CST) of Al–Zn–Mg–Cu alloys can shorten solution time to within 40 s in comparison with 1800 s with traditional solution treatment using a heating furnace. Heating temperature is the key factor in solution treatment. Considering the short heating time of CST, the ultra-high solution temperature over 500 °C of Al–Zn–Mg–Cu alloys was studied in this work. The effects of solution temperatures on the microstructures and the mechanical properties were investigated. The evolution of the second phases was explored and the strengthening mechanisms were also quantitatively evaluated. The results showed that solution time could be reduced to 10 s with the solution temperature of 535 °C due to the increasing dissolution rate of the second phase and the tensile strength of the aged specimen could reach 545 MPa. Precipitation strengthening was the main strengthening mechanism, accounting for 75.4% of the total strength. Over-burning of grain boundaries occurred when the solution temperature increased to 555 °C, leading to the deterioration of the strength.


2013 ◽  
Vol 788 ◽  
pp. 57-60
Author(s):  
Chun Cao ◽  
Chun Dong Zhu ◽  
Chen Fu

Warm pressing forming technology has been gradually applied to the forming of automotive friction materials. How to ensure product performance to achieve the target at the same time achieve the maximum energy saving is the research focus of this study. In this paper, by using finite element method, the field of automotive friction materials in warm pressing forming was analyzed, reveals the relationship between the temperature field and the heating temperature/heating time. Furthermore, the energy consumption was analyzed and compared it with hot pressing forming process. The results will have significant guiding to the process optimization in warm pressing forming.


2014 ◽  
Vol 638-640 ◽  
pp. 1531-1535 ◽  
Author(s):  
Jin Bao Guo ◽  
Lin Liu ◽  
Qiang Wang

In order to solve the shortcomings of traditional methods of concrete curing in winter, proposed self-regulating heating cable new concrete curing methods. Several aspects were considered, about the heating cable length and heating time, heating temperature. According to energy conservation, heating and heat dissipation balance, derived formulas of heating cable normal use length and minimum. As conclusions is shown, first, the normal length design can controlled better heating temperature, it use the cable length and heating time, heating temperature two parameters to control the other parameters. Second, it is better heating efficiency, can be the overall warming state quickly. In addition, when the concrete pouring temperature is above 10 °C, it is not need additional heating, and it can choose minimum length design formula.


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