Structure Analysis and Quality Prediction of DP Steel Engine Hood in the Process of Hot Stamping

2013 ◽  
Vol 791-793 ◽  
pp. 558-561
Author(s):  
Zhi Ping Zhang ◽  
Han Wu Liu ◽  
Tian Xiang Chen ◽  
Zhang Yi Yu
Keyword(s):  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
Forming Limit ◽  
Dp Steel ◽  
Performance Requirements ◽  
Stamping Process ◽  
Work Hardening Rate ◽  
Initial Work ◽  
Parts Manufacturing

Due to its good formability characteristics, such as high strength, high initial work hardening rate, as well as continuous yielding, thin-walled DP steel possesses great advantages of weight loss and security, and has been used to replace ordinary steel for automotive parts manufacturing by a lot of automotive industry. But along with the improvement of the performance of the strength, the high strength steels formability is worsened dramatically, and failure and fracture often occurs in its cold stamping process. So, hot stamping technology must be adopted to make the formability available. In the paper, it took the hot stamping process of DP steel engine hood for example and took DP800 as object of research. The forming limit, variation of major strain, minor strain and thickness, as well as the potential equality defects were analyzed by using eta/DYNAFORM software. The research results show that duplex steel plate can meet the performance requirements of car engine dumping plank forming, which offers theory basis for the production of similar parts.

Computer Simulation of Hot Stamping Process of DP Steel Car Bumper Chain Based on Dynaform

2012 ◽  
Vol 178-181 ◽  
pp. 2877-2880
Author(s):  
Han Wu Liu ◽  
Zhao Hui Liu ◽  
Hui Xiao Li ◽  
Shao Bo Ping
Keyword(s):  
Metal Forming ◽  
Steel Plate ◽  
Hot Stamping ◽  
High Strength ◽  
Spring Back ◽  
Temperature Field Distribution ◽  
Dp Steel ◽  
Performance Requirements ◽  
Stamping Process ◽  
Duplex Steel

Owing to the advantages of weight loss and security, duplex steel plate has been the priority for the saloon car body instead of ordinary one among a majority of engine factories. While there are undesirable phenomena because of its high strength at normal temperature, such as its formability is worsened dramatically, and failure and fracture always occur in the stamping. So hot stamping process must be adopted to make the formability available. Based on the Bumper chain of Beijing Hyundai Reina and taken DP600 high strength steel as research object, this paper analyzes the distributions of stress, strain and thickness changes during the process of sheet metal forming by using eta/DYNAFORM software, simulates the spring-back quantity after hot stamping forming, and the numerical simulation of the temperature field distribution with time during stamping process was done. The result shows that duplex steel plate can meet the performance requirements of automotive chain forming, which offers theory basis for the production of such parts.

Study on the Hot Stamping Process of DP Steel Engine Dumping Plank Based on FEM

2012 ◽  
Vol 236-237 ◽  
pp. 439-442
Author(s):  
Han Wu Liu ◽  
Rui Hua Dong ◽  
Xiao Xia Li ◽  
Shao Bo Ping
Keyword(s):  
Finite Element ◽  
Hot Stamping ◽  
Forming Limit ◽  
Dp Steel ◽  
Blank Holder ◽  
Performance Requirements ◽  
Stamping Process ◽  
Duplex Steel ◽  
Forming Defects ◽  
Cold Stamping

In order to lessen the worsened formability, failures and fractures occurring in the cold stamping process, the hot stamping technology was adopted in the forming of DP steel engine dumping plank. The simulation technology of finite element method was also used to forecast the forming defects in the stamping process of the DP steel engine dumping plank. In the paper, the forming limit, the influences of stamping gaps and the influences of different blank holder force on the stamping part were analyzed by using eta/DYNAFORM software. Meanwhile, the thickness changes and the materials flow conditions of the DP plank during the hot stamping process were also analyzed. Through the experimental analysis, the result of the finite element numerical simulation complied very well with that of actual production results. The research results show that duplex steel plate can meet the performance requirements of car engine dumping plank forming, which offers theory basis for the production of similar parts.

Effect of Heating Parameters on the Part’s Properties in Hot Stamping Process

2012 ◽  
Vol 557-559 ◽  
pp. 2417-2422
Author(s):  
Rui Ge ◽  
An Long ◽  
Yin Chen
Keyword(s):  
Hot Stamping ◽  
High Strength Steels ◽  
Dimensional Accuracy ◽  
High Strength ◽  
Hardness Measurement ◽  
Material Behavior ◽  
Hot Forming ◽  
Accuracy Test ◽  
Stamping Process ◽  
Proper Design

In the automotive industry, the hot forming of high strength steels offers the possibility to obtain significant reduction of weight without affecting the structural performances of final products. Compared with conventional sheet metal forming, the proper design of hot stamping process chain requires the deep knowledge of both interface phenomena and material behavior at high temperatures in order to obtain the desired properties of final products in terms of microstructure and strength characteristics. The work presented in this paper aims at accurately evaluate the effect of heating parameters on the properties of final sheet components produced in hot forming operations. Different from that in the lab, all the samples and parts used for the experimental test were produced in the production line, which can objectively show the manufacturing properties and microstructure character of products in mass. Microstructure evaluation, hardness measurement and dimensional accuracy test after hot stamping were performed and considered. The best heating parameters for the researched hot stamping B-Pillar’s production were obtained through the above research.

Interlaboratory Comparison of Forming Limit Curves for Hot Stamping of High Strength Steels

2009 ◽  
Vol 410-411 ◽  
pp. 297-304 ◽  
Author(s):  
Daniele Pellegrini ◽  
J. Lechler ◽  
Andrea Ghiotti ◽  
Stefania Bruschi ◽  
Marion Merklein
Keyword(s):  
Interlaboratory Comparison ◽  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
Forming Limit ◽  
Testing Procedures ◽  
University Of Padua ◽  
The University ◽  
Forming Limit Curves

The paper presents the approaches followed by two labs – LFT at the University of Erlangen-Nuremberg (Germany) and DIMEG at University of Padua (Italy) – in evaluating formability limits of 22MnB5 sheets when processed under hot stamping conditions. Details about the two testing apparatuses and the testing procedures are outlined, and the results in terms of Forming Limit Curves FLC compared and critically commented.

FE-Simulation of the Heat Transfer by Defined Cooling Conditions during the Hot Stamping Process

2011 ◽  
Vol 473 ◽  
pp. 699-706 ◽  
Author(s):  
Thomas Svec ◽  
Martin Grüner ◽  
Marion Merklein
Keyword(s):  
Heat Transfer ◽  
Mechanical Properties ◽  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
Process Data ◽  
Cold Forming ◽  
Stamping Process ◽  
Characteristic Values ◽  
Tempering Process

Increasing demands regarding security aspects and light weight construction lead to the application of advanced high strength steels (AHSS) and ultra high strength steels (UHSS) in the automotive sector. Due to high process forces and the reduced formability of these steel grades within cold forming new manufacturing technologies like the hot stamping process are required. Furthermore, crash-performance plays an important role in the automotive industry. Therefore functional optimized components are necessary. Hence, actual research work within the community is focused on manufacturing components with local adjusted mechanical properties. One of the strategies to realize the contradictorily requirements regarding energy absorption and structural integrity is the Tailored tempering process where the cooling rates are adjusted by controlled heating or cooling of different tool zones within the hot stamping process. Thereby knowledge concerning the influence of the different heated tool parts on the heat transfer and the resulting mechanical properties is necessary. Furthermore, the applicability and the accuracy of the calculation approaches used for characteristic values like the heat transfer coefficient in the FE-based simulation have to be analyzed and evaluated. Due to this experiments with a tool which exhibits a heated and a cooled zone were performed according to the Tailored tempering process. During the experiments contact pressures and tool temperatures in the heated tool part were varied and analyzed regarding the influence on the heat transfer. Furthermore, the heat transfer coefficients were calculated and verified by a numerical model built according to the experimental setup and the accuracy of the model was evaluated by the comparison of characteristic values calculated from the experimental and numerical process data.

scholarly journals Forming a Flanged Hole When Quenching Press-Hardened Steel for Mechanical Fastening

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 721
Author(s):  
Yongjun Jeon ◽  
Hyunseok Choi ◽  
Dongearn Kim
Keyword(s):  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
Expansion Ratio ◽  
Hardened Steel ◽  
Continuous Increase ◽  
Pilot Hole ◽  
Experimental Apparatus ◽  
Mechanical Fastening ◽  
Hole Flanging

The recent stringent regulations on vehicle safety and reducing CO2 emissions have led to a continuous increase in the application of press-hardened steel (PHS) in automobiles. Similar to other high-strength steels, assembling PHS components using the common welding techniques employed in automotive production lines is significantly difficult because of the surface coating layers and the additives within. This difficulty in post-processing, attributed to its high strength, also limits the mechanical fastening of PHS components. Therefore, this study aims to develop a process for forming a structure enabling mechanical fastening by sequentially applying piercing and hole-flanging operations during the hot stamping process. Our experimental apparatus was designed to perform the hole-flanging operation after the piercing operation within a single stroke at a specific temperature during the quenching process of PHS. At high temperatures of 440 °C or higher, the hole-flanging process was conducted in a direction opposite to that of the piercing operation for creating the pilot hole. An extruded collar with a height of 8.0 mm and a diameter of 17.5 mm was achieved, which is hole expansion ratio(HER) of 82.5%.

The Microstructure and Formability Study on DP Steel of Lightweight Automobile

2011 ◽  
Vol 704-705 ◽  
pp. 1465-1472
Author(s):  
Jin Wu ◽  
Da Sen Bi ◽  
Liang Chu ◽  
Jian Zhang ◽  
Yun Tao Li
Keyword(s):  
Mechanical Property ◽  
Work Hardening ◽  
High Strength Steel ◽  
High Strength ◽  
Mathematic Model ◽  
Theoretical Research ◽  
Forming Limit ◽  
Strain Hardening Exponent ◽  
Dp Steel ◽  
Better Than

Dual phase (DP) steel is a high strength steel for auto-panel. In this paper, mechanical property, forming ability, baked-hardening and work hardening properties of high strength steel DP450 are studied by experiments, and compared with those of steel MS6000.And theoretical research on predicting the forming limit of steel DP450 by the NADDRG model. The established mathematic model for relativity is of practical usefulness. Experimental results reveal that the yield strength of steel DP450 is about 7.2% lower than the MS6000,and the break strength increases by 18.9%,while the elongation increases by 19%.The strain hardening exponent of steel DP450 are superior to those of MS6000.The results show that mechanical property of high strength steel DP450 is better than that of MS6000,while forming ability of DP450 is not lower than that of MS6000.And baked-hardening and work hardening properties of steel DP450 are better than those of MS6000.The steel sheet DP450 owned a good forming ability.

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