Current Trends of Hydroforming Process Into Automotive Body Structure and Chassis Applications

2007 ◽  
Author(s):  
Ramakrishna Koganti ◽  
Jason Balzer ◽  
Klaus Hertell
Keyword(s):  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
The Body ◽  
Instrument Panel ◽  
Forming Process ◽  
Automotive Body ◽  
Current Trends ◽  
Structural Applications ◽  
Hydroforming Process

Recent low emission, lightweight, safety requirements, automotive manufacturers are implementing lighter and stronger materials and new manufacturing processes into body structural components. Typical widely used forming process in automotive body structures is stamping process. Other forming processes currently used in body structural applications are hydroforming, Rollforming and hot stamping processes. Initially, hydroforming process was used for chassis applications. Few applications of chassis are cross members, engine cradle, instrument panel (IP) beams, and bumper beams. Recently, a few automotive manufacturers are already implemented the hydroforming process into front end structures. Hydroform process gives more part consolidation, and perhaps even weight reduction. However, depending on applications some brackets may be needed to attach other components. Some of the issues related to bracket attachments can be avoided in the design phase. Audi A2, and Chrysler Pacifica have implemented roof rails in the body structures arena. Latest developments are even pushing the hydroforming process into High Strength Steels arena. Pontiac Solstice and Saturn Sky implemented Dual Phase 600 material on the chassis rails. In this paper, current trends of hydroforming process with advanced high strength steels (AHSS) will be discussed. Hydroforming process involves, bending, preforming (low pressure), and final forming (high pressure) with mechanical properties of DP780 material at various stages of the hydroforming process will be discussed.

Dissimilar Material Joint Strength and Structure for Friction Stir Forming Process

2014 ◽  
Author(s):  
Kenneth A. Ogata ◽  
Sladjan Lazarevic ◽  
Scott F. Miller
Keyword(s):  
Failure Modes ◽  
Dissimilar Materials ◽  
High Strength Steels ◽  
High Strength ◽  
Forming Process ◽  
Experimental Conditions ◽  
Friction Stir ◽  
Automotive Body ◽  
Neck Fracture ◽  
Ultra High Strength Steels

Mass reduction of automotive body structures is a critical part of achieving reduced CO2 emissions in the automotive industry. There has been significant work on the application of ultra high strength steels and aluminum alloys. However, the next paradigm is the integrated use of both materials, which creates the need to join them together. Friction stir forming is a new environmentally benign manufacturing process for joining dissimilar materials. The concept of this process is stir heating one material and forming it into a mechanical interlocking joint with the second material. In this research the process was experimentally analyzed in a computer numerical controlled machining center between aluminum and steel work pieces. The significant process parameters were identified and their optimized settings for the current experimental conditions defined using a design of experiments methodology. Three failure modes were identified (neck fracture, aluminum sheet peeling, and bonding delamination i.e. braze fracture). The overall joint structure and grain microstructure were mapped along different stages of the friction stir forming process. Two layers were formed within the aluminum, the thermo-mechanical affected zone that had been deformed due to the contact pressure and angular momentum of the tool, and the heat affected deformation zone that deformed into the cavity.

Consideration of Elastic Tool Deformation in Numerical Simulation of Hydroforming with Granular Material Used as a Medium

2011 ◽  
Vol 473 ◽  
pp. 707-714 ◽  
Author(s):  
Martin Grüner ◽  
Marion Merklein
Keyword(s):  
Numerical Simulation ◽  
Granular Material ◽  
Elevated Temperatures ◽  
High Strength Steels ◽  
High Strength ◽  
Appropriate Technology ◽  
The Body ◽  
Warm Forming ◽  
Forming Process ◽  
Blank Holder

The use of high and ultra high strength steels in modern bodies in white raises steadily since the 1980’s. This trend is caused by the consumers’ wish of low fuel consuming cars with an increased passenger’s safety. The processing of these steels brings new challenges e.g. high flow stresses and a low formability at room temperature or high tool loads. These challenges can be resolved by warm forming at temperatures up to 600 °C reducing the flow stresses and increasing formability. For the production of complex parts that can not be produced by deep drawing hydroforming is an appropriate technology which can also help to reduce the number of parts and thus the weight of the body in white. Nowadays typical fluids used for hydroforming are only temperature stable up to about 330 °C so that it is not possible to combine the benefits of warm forming and hydroforming. Media like gases and fluids tend to leakage during the process which can only be avoided by a sealing or high blank holder forces. A new approach is the use of ceramic beads as medium for hydroforming at elevated temperatures. Building up a heatable tool for hydroforming with granular material used as medium makes it necessary to consider thermal conductivity so that there is a need of thick insulation plates. These insulation plates show high elastic deformations affecting the blank holder forces during the forming process. Measurements of the compressibility of these plates and implementation in numerical simulation allow a significant increase of the prediction accuracy of the model. A comparison of real part geometry and numerical results from models with and without consideration of elastic deformation will be given.

Springback Investigation in Roll Forming of a V-Section

2014 ◽  
Vol 553 ◽  
pp. 643-648 ◽  
Author(s):  
Akbar Abvabi ◽  
Joseba Mendiguren ◽  
Bernard F. Rolfe ◽  
Matthias Weiss
Keyword(s):  
Elastic Modulus ◽  
Continuous Process ◽  
High Strength Steels ◽  
Shell Element ◽  
High Strength ◽  
Material Model ◽  
The Body ◽  
Roll Forming ◽  
Forming Process ◽  
Advanced High Strength Steels

To have fuel efficient vehicles with a lightweight structure, the use of High Strength Steels (HSS) and Advanced High Strength Steels (AHSS) in the body of automobiles is increasing. Roll forming is used widely to form AHSS materials. Roll forming is a continuous process in which a flat strip is shaped to the desired profile by passing through numerous sets of rolls. Formability and springback are two major concerns in the roll forming of AHSS materials. Previous studies have shown that the elastic modulus (Young’s modulus) of AHSS materials can change when the material undergoes plastic deformation and the main goal of this study is to numerically investigate the effect of a change in elastic modulus during forming on springback in roll forming. Experimental loading-unloading tests have been performed to obtain the material properties of TRIP 700 steel and incorporate those in the material model used in the numerical simulation of the roll forming process. The finite element simulations were carried out using MSC-Marc and two different element types, a shell element and a solid-shell element, were investigated. The results show that the elastic modulus diminution due to plastic strain increases the springback angle by about 60% in the simple V-section roll forming analyzed in this study.

scholarly journals Effects of Al-Si Coating Thickness on 22MnB5 in Hot Stamping Wear

2020 ◽  
Vol 58 (8) ◽  
pp. 573-582
Author(s):  
Min Ki Ji ◽  
Hyunsung Son ◽  
Jinkeun Oh ◽  
Seongwoo Kim ◽  
Kyungmok Kim ◽  
...  
Keyword(s):  
Coating Thickness ◽  
Hot Stamping ◽  
Weight Ratio ◽  
High Strength Steels ◽  
High Strength ◽  
Wear Behaviour ◽  
Friction Test ◽  
Forming Process ◽  
Coating Materials ◽  
Tool Surface

Al-Si coated ultra-high strength steels (UHSS) are widely used in automotive applications because of their high strength-to-weight ratio, corrosion protection and good weldability. The hot stamping (also called hot press forming) process is an effective and suitable technique for producing automotive parts from Al-Si coated UHSS. However, critical issues, such as the transfer of the coating materials and the build-up of these materials on the tool surface, have been encountered. These defects affect tool life and product quality. The wear behaviour of Al-Si coated 22MnB5 and Cr coated SKD11 tool was investigated using a high temperature friction test which mimicked the actual hot stamping environment. Two kinds of Al-Si coated 22MnB5 with ~19.6 (AlSi-A) and ~29.3 (AlSi-B) µm coating thicknesses were used in this study. After the friction test the coated layer of AlSi-A was found to be worn up to the diffusion layer, while for AlSi-B, the coating layer mostly remained after the friction test. Adhesive wear predominantly occurred on the tool surface in both cases, but the wear increased significantly in case of AlSi-B. This suggests that the coating thickness and the associated surface roughness are critical factors affecting wear behaviour.

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%.

scholarly journals Tribological Behavior of Laser Textured Hot Stamping Dies

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Andre Shihomatsu ◽  
Sergio Tonini Button ◽  
Iris Bento da Silva
Keyword(s):  
Surface Topography ◽  
High Pressures ◽  
Hot Stamping ◽  
High Strength Steels ◽  
High Strength ◽  
Experimental Tests ◽  
Textured Surface ◽  
Laser Texturing ◽  
Stamping Dies ◽  
Before And After

Hot stamping of high strength steels has been continuously developed in the automotive industry to improve mechanical properties and surface quality of stamped components. One of the main challenges faced by researchers and technicians is to improve stamping dies lifetime by reducing the wear caused by high pressures and temperatures present during the process. This paper analyzes the laser texturing of hot stamping dies and discusses how different surfaces textures influence the lubrication and wear mechanisms. To this purpose, experimental tests and numerical simulation were carried out to define the die region to be texturized and to characterize the textured surface topography before and after hot stamping tests with a 3D surface profilometer and scanning electron microscopy. Results showed that laser texturing influences the lubrication at the interface die-hot sheet and improves die lifetime. In this work, the best texture presented dimples with the highest diameter, depth, and spacing, with the surface topography and dimples morphology practically preserved after the hot stamping tests.

Characterization of a AISI/SAE 4340 Steel in Different Microstructural Conditions

2014 ◽  
Vol 775-776 ◽  
pp. 136-140 ◽  
Author(s):  
Renato Araujo Barros ◽  
Antonio Jorge Abdalla ◽  
Humberto Lopes Rodrigues ◽  
Marcelo dos Santos Pereira
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Aviation Industry ◽  
Sodium Metabisulfite ◽  
Aerospace Applications ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
Structural Applications ◽  
Ultra High Strength Steels ◽  
Pin On Disk

The 4340 are classified as ultra-high strength steels used by the aviation industry and aerospace applications such as aircraft landing gear and several structural applications, usually in quenched and tempered condition. In this situation occurs reduction of toughness, which encourages the study of multiphasic and bainític structures, in order to maintain strength without loss of toughness. In this study, ferritic-pearlitic structure was compared to bainitic and martensitic structure, identified by the reagents Nital, LePera and Sodium Metabisulfite. Sliding wear tests of the type pin-on-disk were realized and the results related to the microstructure of these materials and also to their hardnesses. It is noted that these different microstructures had very similar behavior, concluding that all three tested pairs can be used according to the request level.

Relationship between Microstructure and Mechanical Properties in Q&P-Steels

2016 ◽  
Vol 879 ◽  
pp. 1933-1938 ◽  
Author(s):  
Richard G. Thiessen ◽  
Georg Paul ◽  
Roland Sebald
Keyword(s):  
Mechanical Properties ◽  
Dual Phase Steel ◽  
High Strength Steels ◽  
High Strength ◽  
The Body ◽  
Advanced High Strength Steels ◽  
Passenger Safety ◽  
Back Scattering ◽  
Body In White ◽  
Expected Increase

Third-Generation advanced high strength steels are being developed with the goal of reducing the body-in-white weight while simultaneously increasing passenger safety. This requires not only the expected increase in strength and elongation, but also improved local formability. Optimizing elongation and formability were often contradictory goals in dual-phase steel developments. Recent results have shown that so-called "quench and partitioning" (Q&P) concepts can satisfy both requirements [1]. Many Q&P-concepts have been studied at thyssenkrupp Steel Europe. Thorough investigation of the microstructure has revealed relationships between features such as the amount, morphology and chemical stability of the retained austenite and the obtained mechanical properties. An evaluation of the lattice strain by means of electron-back-scattering-diffraction has also yielded a correlation to the obtained formability. The aim of this work is to present the interconnection between these microstructural features and propose hypotheses for the explanation of how these features influence the macroscopically observed properties.

Sign in / Sign up

Export Citation Format

Share Document