Suitability analysis of a polymer–metal hybrid technology based on high-strength steels and direct polymer-to-metal adhesion for use in load-bearing automotive body-in-white applications

2009 ◽  
Vol 209 (4) ◽  
pp. 1877-1890 ◽  
Author(s):  
M. Grujicic ◽  
V. Sellappan ◽  
S. Kotrika ◽  
G. Arakere ◽  
Andreas Obieglo ◽  
...  
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Suitability Analysis ◽  
Load Bearing ◽  
Hybrid Technology ◽  
Automotive Body ◽  
Polymer Metal ◽  
Body In White

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.

Influence of Weld Imperfections on the Fatigue Behaviour of Resistance Spot Welded Advanced High Strength Steels

2014 ◽  
Vol 891-892 ◽  
pp. 1445-1450 ◽  
Author(s):  
Michael Rethmeier
Keyword(s):  
Fatigue Life ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Behaviour ◽  
Whole Body ◽  
Surface Cracks ◽  
Significant Drop ◽  
Resistance Spot ◽  
Advanced High Strength Steels ◽  
Body In White

The use of advanced high strength steels (AHSS) in the automotive body-in-white is increasing. Those steels are predominantly joined by resistance spot welding. For the performance of the whole body-in-white, the fatigue behaviour is of high interest, especially as during production, weld imperfections such as cracks and manufacturing-related gaps cannot be avoided. In this study the TRIP steel HCT690 was used as it is a typical advanced high strength steel in automotive production. The investigation into the influence of cracks was split depending on the crack location in the weld area. Surface cracks in the electrode indentation area as well as in the heat affected zone were produced during welding and analyzed. The results showed that surface cracks independent of their position have no effect on the fatigue life. The produced internal imperfections have shown only a marginal impact on the fatigue life. It was ascertained that gaps of 3 mm lead to a significant drop in fatigue life compared to gap free shear tension samples under a load ratio R of 0.1. This fact was attributed to decreased stiffness, higher transverse vibration and higher rotation between the sheets. Furthermore, FE-simulations have shown an increase in local stresses in gapped samples.

Experimental Investigations on Wear Resistance Characteristics of Alternative Die Materials for Stamping of Advanced High Strength Steels (AHSS)

2008 ◽  
Author(s):  
O¨mer Necati Cora ◽  
Muammer Koc¸
Keyword(s):  
Wear Resistance ◽  
Surface Hardness ◽  
High Strength Steels ◽  
High Strength ◽  
Wear Testing ◽  
Experimental Investigations ◽  
Advanced High Strength Steels ◽  
Automotive Body ◽  
Die Materials ◽  
Aisi D2

Newer sheet alloys (such as Al, Mg, and advanced high strength steels) are considered for automotive body panels and structural parts to achieve lightweight construction. However, in addition to issues with their limited formability and high springback, tribological conditions due to increased surface hardness and higher work hardening effect necessitate the use of improved alternative die materials, coatings, lubricants to minimize the wear-related issues in stamping of such lightweight materials. This study aims to investigate and compare the wear performances of seven (7) different die materials (AISI D2, Vanadis 4, Vancron 40, K340 ISODUR, Caldie, Carmo, 0050A) using a newly developed wear testing method and device. We used DP600 sheets in the tests. Our results showed that almost all of the recently developed specially-alloyed die materials demonstrated higher wear resistance performance when compared with the performance of AISI D2 die material.

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.

scholarly journals Specimen's Geometry Related Influences on Load-Bearing Capacity of Joining Aluminium and UHSS by Innovative Shear-Clinching

2017 ◽  
Vol 6 (4) ◽  
pp. 19 ◽  
Author(s):  
Rejane Horhold ◽  
Martin Muller ◽  
Marion Merklein ◽  
Gerson Meschut
Keyword(s):  
Lightweight Design ◽  
High Strength ◽  
Single Step ◽  
Economic Conditions ◽  
Automotive Body ◽  
Joining Technology ◽  
Strength Capacity ◽  
Body In White ◽  
Design Requirements ◽  
Manganese Steels

Economic conditions as well as comfort and safety-related requirements lead to lightweight design especially in automotive body-in-white production processes. The consequential multi-material mix limits the reliability of conventional thermal joining technologies. Innovative mechanical joining technologies need to be established. Following the lightweight-design requirements, next step for weight-reduction would be the renunciation of additional elements. Clinching technologies support this idea by creating a form- and force-fitting joint, but are limited to the formability of the joining partners. Joining by forming without additional elements even of hot formed ultra-high-strength manganese steels and ductile aluminium can be realised by shear-clinching. A precisely coordinated tool setup initialises a crack in the die-sided material with limited formability without harming the punch-sided ductile aluminium. This paper presents current and detailed investigations of the influences of mechanical loads on strength capacity of multi-material joints using shear-clinching technologies. The results clearly show the promising potential and challenges of this innovative single-step joining technology for multi-material mixes.

The Potential of a Clinch-Lock Polymer Metal Hybrid Technology for Use in Load-Bearing Automotive Components

2009 ◽  
Vol 18 (7) ◽  
pp. 893-902 ◽  
Author(s):  
M. Grujicic ◽  
V. Sellappan ◽  
G. Arakere ◽  
Norbert Seyr ◽  
Andreas Obieglo ◽  
...  
Keyword(s):  
Load Bearing ◽  
Hybrid Technology ◽  
Automotive Components ◽  
Polymer Metal

State-of-Art High Strength Steel Sheets for the Automotive Application

2007 ◽  
Vol 539-543 ◽  
pp. 4369-4374 ◽  
Author(s):  
Toshiaki Urabe ◽  
Fusato Kitano ◽  
Takeshi Fujita ◽  
Yuji Yamasaki ◽  
Yoshihiro Hosoya
Keyword(s):  
Mechanical Properties ◽  
Low Carbon Steel ◽  
High Strength Steels ◽  
High Strength ◽  
Grain Structure ◽  
Solid Solution Hardening ◽  
Automotive Application ◽  
Continuous Annealing ◽  
Low Carbon ◽  
Body In White

New type of IF cold-rolled high strength steels (HSSs) with the strength level of 390 and 440MPa have been developed under the chemistry of the extra-low carbon steel containing around 60ppm C with an intentional addition of niobium by hybridizing the precipitation hardening with niobium carbides and the supplemental solid-solution hardening. In this steel, Precipitation Free Zone (PFZ) nearby recrystallized grain boundaries forms during continuous annealing. This structure leads to unique mechanical properties such as lower yielding and superior anti-secondary-work embrittlement under fine grain structure strictly required for the exposed panels in Body-in-White. Principles of the unique mechanical properties of the steel are introduced related with the formation of PFZ during annealing, and the results of further approach to improve them as the state-of-the-art product, which is widely used for the exposed panels in Body in White, are introduced in the paper.

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