Hot forming limit curves for numerical press hardening simulation of AISI 420C

Abstract

A possible alternative to the established press hardening steel 22MnB5 are hot formed martensitic chromium steels. Both strength and ductility of the martensitic chromium steels can reach very high values with appropriate heat treatments. Therefore, car body parts with high crash safety can be produced by hot forming martensitic chromium steels. To identify the formability of a sheet metal, forming limit curves are state of the art. Conventional forming limit curves are recorded at room temperature and do not adequately describe the forming capacity for hot sheet metal forming as it strongly depends on temperature. Therefore, in this paper, an experimental-numerical method for determining quasi-isothermal FLC at high forming temperatures is applied to the martensitic chromium steel AISI 420C (X46Cr13) for forming temperatures between 750-1,050 °C according to its process route. The results show an increase of the formability with rising forming temperature with the highest at 1,050 °C.

Development of Measurement Equipment and Experimental and Numerical Simulation Studies for Warm Forming Limits of High-Strength Steel

“…After the completion of the forming simulation of DP600 steel at 300 °C and at room temperature, taking the specimen IX at 300 °C as an example, the curve for the contact force of the center point between the punch and sheet was extracted at the time of the maximum force of the punch with the judgment method [ 19 ] as shown in Figure 9 . When the punch was in contact with the sheet material, the forming force (Y value) reached the peak value.…”

“…Bandyopadhyay et al [ 18 ] adopted the LS-DYNA 971 numerical simulation software and used the modified Marciniak–Kuckzinki (MK) forming limit diagram acquisition method to predict relative parameters of the forming limits. Behrens et al [ 19 ] adopted the ABAQUS finite element software to carry out numerical simulation calculations for the bulging process and obtained the FLD at room temperature for high-strength 7050 aluminum alloy and the FLD at a warm temperature for the AZ31 magnesium alloy. In addition to the above software, the DYNAFORM software has also been widely applied in numerical simulations of the forming process of sheet materials due to its high computing efficiency and the absence of requirements for sub-program setting of material parameters.…”

Finite Element and Finite Volume Modelling of Friction Drilling HSLA Steel under Experimental Comparison

“…To predict the material failure in sheet metals, usually forming limit curves are used [20]. Due to the deformation during friction drilling, however, a stress state is present, which is not represented by forming limit curves.…”

“…Finally, the force-displacement curves from the experiments and simulations were compared to evaluate the moment of failure prediction by the simulation. To predict the material failure in sheet metals, usually forming limit curves are used [20]. Due to the deformation during friction drilling, however, a stress state is present, which is not represented by forming limit curves.…”

Simulation and Experimental Study on Roll-Forming Limit of Cup

“…The roll-forming process was compared with the traditional p aspects of material utilization, productivity, forming force, dies cost machining time [20,21]. This method has successfully formed cups with a curved rotary profile [22,23], but there is no basis for determining the roll forming limit, which is one of the most important parameters to determine the forming process [24][25][26][27][28]. During the shaping of roll forming, only the triangular flash formed on the outer surface of the cup in the roll pre-forming is eliminated, and the deformation is small, so only the roll pre-forming limit needs to be studied.…”