Temperature distribution of boron-manganese sheet metal blank by induction heating in application for hot stamping

Engineering ◽  
2014 ◽  
Vol 12 (5) ◽  
pp. 21 ◽  
Author(s):  
Ya Xu ◽  
Peixing Liu ◽  
Zijian Wang ◽  
Yisheng Zhang
2014 ◽  
Vol 622-623 ◽  
pp. 279-283 ◽  
Author(s):  
Eiichi Ota ◽  
Yasuhiro Yogo ◽  
Takamichi Iwata ◽  
Noritoshi Iwata ◽  
Kenjiro Ishida ◽  
...  

A forming process for heated sheet metal, such as hot-stamping, has limited use in deformable shapes. Higher temperature areas which have not yet come into contact with dies are more easily deformed; therefore, local deformation occurs at these areas which leads to breakage. To improve the formability of heated sheet metal, a deformation control technique utilizing the temperature dependence of flow stress is proposed. This technique can suppress local deformation by partial cooling around potential cracking areas to harden them before forming. In order to apply this technique to a variety of product shapes, a procedure to determine a suitable initial temperature distribution for deep drawing and biaxial stretching was developed with a coupled thermal structural simulation. In this procedure, finite elements exceeding forming limit strain are highlighted, and an initial temperature distribution is defined with areas of decreased temperature around the elements to increase their resistance to deformation. Subsequently, the partial cooling technique was applied to a deep drawing test with a heated steel sheet. The results of the experiment showed that the proposed technique improved 71% in the forming limit depth compared with results obtained using a uniform initial temperature distribution.


2018 ◽  
Vol 99 (1-4) ◽  
pp. 583-593 ◽  
Author(s):  
Dong Kyu Kim ◽  
Young Yun Woo ◽  
Kwang Soo Park ◽  
Woo Jeong Sim ◽  
Young Hoon Moon

Author(s):  
A.A. Shcherba ◽  
◽  
A.D. Podoltsev ◽  
I.M. Kucheriava ◽  
V.M. Zolotarev ◽  
...  

The model for the computation of thermal processes in induction heating installations with moving ingots is developed using equivalent thermal circuits. The controlled current sources as additional elements in the model are used to take into account the convective heat transfer along the moving ingot. The model is implemented in the program Matlab/Simulink and makes it possible to determine the temperature distribution along the ingot under steady-state heating conditions. The results are compared with data obtained by the alternative method which is based on the electromagnetic and thermal field theory and realized in the Comsol program. As shown the computational results by two methods concerning the temperature distribution along the ingot are in good agreement. The existing advantages and shortcomings of the used approaches are discussed. Ref. 8, fig. 3, table.


2019 ◽  
Vol 6 ◽  
pp. 16
Author(s):  
Alexander Horn ◽  
Marion Merklein

Today, manufacturing of structural car body parts faces several challenges, like forming accuracy, passenger safety and lightweight design. One possibility to fulfill these partially rivalling demands is the application of hot stamped components. The combination of hot forming and in-die quenching reduces not only springback, but also results in tensile strengths of more than 1500 MPa. Besides conventional hot stamping, the process can be adapted to manufacture parts with tailored properties. One of the biggest issues of these state-of-the-art processes is the formation of extensive transition zones due to heat transfer. A promising approach to adjust the mechanical properties with a minimized transition zone is tailored carburization of sheet metal. Therefore, the parts are locally coated with graphite, heat treated and subsequently quenched. In this work, the time variant process of carbon diffusion is investigated. Sheets with two different thicknesses are carburized and quenched. The resulting mechanical properties are analyzed using uniaxial tensile tests and microhardness measurements. On this basis, a process window is identified. Furthermore, the applicability of EDX and WDX analysis for the measurement of carbon concentration is investigated within this work.


2018 ◽  
Vol 190 ◽  
pp. 08004 ◽  
Author(s):  
Alexander Horn ◽  
Marion Merklein

Today’s manufacturing of structural car body parts faces several challenges, like forming accuracy and passenger safety. Besides these two requirements, lightweight design plays an important role. One possibility to fulfill these partially rivalling demands is the application of hot stamped parts. The combination of hot forming and in die quenching reduces not only springback, but also results in tensile strengths of up to 1500 MPa. This makes a simultaneous reduction of sheet thickness and therefore weight reduction possible. Further development enabled a tailored adjustment of mechanical properties, for example by applying different cooling conditions along the parts. One of the biggest issues of these state of the art processes is the formation of a transition zone due to heat transfer. A promising approach to adjust the mechanical properties with a minimized transition zone is the carburization of sheet metal. Therefore, the parts are coated with graphite, heat treated and subsequently quenched. In this work, the time variant process of carbon diffusion is investigated. Sheets with two different thicknesses are carburized and quenched. The resulting mechanical properties are analyzed using uniaxial tensile tests and microhardness measurements. The results are correlated with the carbon content measured by EDX-analysis.


2020 ◽  
Vol 12 (7) ◽  
pp. 168781402093848
Author(s):  
Kangjie Song ◽  
Jing Guan ◽  
Kunmao Li ◽  
Jing Liu

The axial and radial temperature distributions of an induction heating workpiece considerably impact the subsequent nitriding process. To obtain a satisfactory temperature distribution, an equal pitch coil, a variable pitch coil, and a variable radius coil were designed. Furthermore, an induction heating model that exhibits electromagnetic and temperature field coupling was established; thus, the effects of the current density and frequency on the heating efficiency and temperature distribution of the workpiece were analyzed and compared. In addition, an induction heating experiment was conducted to verify the model. According to the numerical results, the variable radius coil can reduce the axial temperature difference in comparison with equal pitch coil and variable pitch coil. Hence, the workpiece heated using the variable radius coil can achieve a better temperature distribution when compared with those heated by the equal pitch coil and variable pitch coil, with appropriate current density and current frequency values.


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