Formability Analysis on Ultra-High Strength Steel for Automotive Parts Using Finite Element Simulation

2021 ◽  
Vol 1018 ◽  
pp. 137-144
Author(s):  
Aeksuwat Nakwattanaset ◽  
Surasak Suranuntchai
Keyword(s):  
Finite Element ◽  
Metal Forming ◽  
High Strength Steel ◽  
Research Work ◽  
High Strength ◽  
Forming Limit ◽  
Body Frame ◽  
First Case ◽  
Ultra High Strength Steel ◽  
Automotive Parts

Finite Element Method (FEM) is one of the most popular methods in the automotive industry to reduce problems, time and wastes in production processes. This method can predict the metal forming processes with computer modeling before making forming tools. In sheet metal forming analysis, Forming Limit Diagram (FLD) is one of the most important indicators in FEM, it can tell each forming regions such as cracks, wrinkles and safe zone. However, the FLD that has automatically created in finite element program isn’t enough accurate. Then, the main objective of this research work was to generate FLD of the ultra-high strength steel: NSC980D that usually has been used in auto body frame by using Nakajima's tests. Then, the generated FLD was used to simulate the forming of the automotive parts for solving the cracks caused during the forming along with the Hill’s 1948 material model. The Keeler’s FLD, which is generated automatically by the commercial software applied, was plotted for comparison during simulation, as well. Drawing process of the panel front was investigated by applying FEM simulating tool: PAMSTAMP to analyze the formability and to determine the optimal forming parameters under suitable service conditions. The main parameters of interest were the part and blank configuration. A number of corrections were successively made to successfully form the part. From the analysis of 2 case studies, it was found that tearing was occurred in the first case results. When the forming force was reduced from 15 tons to 9 tons in the second case, the complete forming without tearing and similar like actual forming at the same conditions had been taken place in the second results.

Ultra-High Strength Steel Hot Stamping Technology and Devices

2014 ◽  
Vol 1063 ◽  
pp. 237-243
Author(s):  
Zhong De Shan ◽  
Qin Tai Yan ◽  
Chao Jiang ◽  
Wen Juan Rong
Keyword(s):  
Tensile Strength ◽  
High Strength Steel ◽  
Hot Stamping ◽  
Research Work ◽  
High Strength ◽  
Parameters Optimization ◽  
Systematic Research ◽  
China Academy ◽  
Ultra High Strength Steel ◽  
Vehicle Structure

Ultra High Strength Steel (UHSS) hot stamping technology is a special process which can enhance the steel tensile strength to 1500MPa. Appling this technology in producing vehicle structure parts can make car lighter and safer. In China there are more and more automobile enterprises adopt this technology. To master and extend the skill, China Academy of Machinery Science & Technology (CAM) have done systematic research, such as the strengthen mechanism of the steel, hot stamping key devices designing, forming and quenching integrated mould designing, stamping process parameters optimization, etc.. By now, CAM has mastered the mass production technology of vehicle parts, which can guarantee its shape and tensile strength, and produced such typical parts as door-beam, B pillar, etc.. The paper is an introduction of the research work and achievement about UHSS hot stamping developed by CAM.

GPU Accelerated Finite Element Simulation for Ultra-High Strength Steel Quenching

2013 ◽  
Vol 842 ◽  
pp. 337-340
Author(s):  
Chao Wang ◽  
Bin Zhu ◽  
Liang Wang ◽  
Yi Lin Wang ◽  
Yi Sheng Zhang
Keyword(s):  
Finite Element ◽  
Latent Heat ◽  
High Strength Steel ◽  
Thermal Contact ◽  
Hot Stamping ◽  
High Strength ◽  
Heat Processing ◽  
Processing Unit ◽  
Ultra High Strength Steel ◽  
Quenching Process

During the hot stamping of ultra-high strength steel (UHSS), the quenching effect of the mold on the sheet plays an important role to achieve the transition from austenite to martensite. Thus a finite element model for the quenching process of UHSS is established in this paper. The key points of the model include contact thermal conduction and the latent heat processing of phase transforming. Finite element program has been developed to calculate the temperature field of the UHSS quenching process, and temperature measurement device was used to get the temperature-time curve of the mold and the sheet to validate the calculation results. It can be concluded that the latent heat and thermal contact resistance have a critical influence on the temperature filed of the sheet during the hot stamping process. Finally, the parallel computation technology based on GPU(Graphics processing unit) was adopted to accelerate the calculation.

Application of Servo Presses to Sheet Metal Forming

2011 ◽  
Vol 473 ◽  
pp. 27-36 ◽  
Author(s):  
Kenichiro Mori
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
High Strength Steel ◽  
Hot Stamping ◽  
High Strength ◽  
Forming Limit ◽  
Ac Servo ◽  
Conventional Machine ◽  
High Flexibility

Mechanical AC servo presses having high flexibility for control of motion have been recently developed. In these presses driven by servo motors, the slide motion is accurately controlled by real-time feedback of ram position measured with sensors like the conventional machine tools, and thus complicated motion is attainable. The application of servo presses to sheet metal forming processes is reviewed in the present paper. The springback in bending was reduced by bottoming and re-striking. In deep drawing, the forming limit of high strength steel sheets was improved by detaching tools from the sheet, and the wrinkling was prevented by applying a stepwise motion. A hot stamping process using rapid resistance heating and a servo press was developed to produce ultra-high strength steel parts.

Hot Forming Analysis of Car Door Bar for Ultra High Strength Steel

2010 ◽  
Vol 160-162 ◽  
pp. 836-841
Author(s):  
Yun Kai Gao ◽  
Da Wei Gao ◽  
You Zhi Deng ◽  
Wei Cao
Keyword(s):  
High Strength Steel ◽  
Thickness Distribution ◽  
High Strength ◽  
Simulation Method ◽  
Hot Forming ◽  
Forming Limit ◽  
Boron Steel ◽  
Shell Elements ◽  
Forming Simulation ◽  
Ultra High Strength Steel

Ultra high strength steel plays an important role of light weighting in automotive industry. The hot forming simulation of car door bar is processed with 22MnB5 ultra high strength boron steel. FEM is built with the 12 nodes shell elements and MAT 106 is selected in LS-DYNA. The hot forming processes include two heat transfers. One is the process from the oven to the tools after the blank is heated. The other is the process after the blank contacts the tools. The hot forming simulation results are obtained by LS-DYNA. The results show that the thickness distribution, the forming limit and the maximum effective plastic strain and other performances attain to standards. It is proved that the hot forming simulation method is correct.

Dynamically recrystallized austenitic grain in a low carbon advanced ultra-high strength steel (A-UHSS) microalloyed with boron under hot deformation conditions

2012 ◽  
Vol 1485 ◽  
pp. 143-148 ◽  
Author(s):  
I. Mejía ◽  
E. García-Mora ◽  
G. Altamirano ◽  
A. Bedolla-Jacuinde ◽  
J. M. Cabrera
Keyword(s):  
Grain Size ◽  
Hot Deformation ◽  
High Strength Steel ◽  
Picric Acid ◽  
True Strain ◽  
Research Work ◽  
High Strength ◽  
Low Carbon ◽  
Ultra High Strength Steel ◽  
Wide Range

ABSTRACTThis research work studies the dynamically recrystallized austenitic grain size (Drec) in a new family of low carbon NiCrCuV advanced ultra-high strength steel (A-UHSS) microalloyed with boron under hot deformation conditions. For this purpose, uniaxial hot-compression tests are carried out in a low carbon A-UHSS microalloyed with different amounts of boron (14, 33, 82, 126 and 214 ppm) over a wide range of temperatures (950, 1000, 1050 and 1100°C) and constant true strain rates (10−3, 10−2and 10−1s−1). Deformed samples are prepared and chemically etched with a saturated aqueous picric acid solution at 80°C in order to reveal theDrecand examined by light optical (LOM) and scanning electron microscopy (SEM). TheDrecis related to the Zener-Hollomon parameter (Z), and thereafter theDrecdivided by Burger's vector (b) is related to the steady state stress (σss) divided by the shear modulus (µ) (Derby model). Results shown that theDrecin the current steels is fine (≈ 23 μm) and almost equiaxed, and the recrystallized grain size-flow stress relationship observed after of plastic deformation is consistent with the general formulation proposed by Derby. It is corroborated that boron additions to the current A-UHSS do not have meaningful influence on theDrec.

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