New Steel Body Sicherer und wirtschaftlicher Karosserieleichtbau mit Stahl

Advanced Structured Materials

Weber

2011

The application of the weldbonding technique for the lightweight body shell design in the steel car manufacturing is described. For different steel grades of advanced high strength steels and ultra high strength steels and some selected adhesive systems, the influence of the base metal strength and the viscosity of the applied adhesive on the weldbonding process and the weldbonded joints are analyzed. This was done with a focus on the specific requirements for the applications of the automotive industry. In detail, these are discussed regarding process reliability, the mechanical and metallurgical properties of joints, the failure types and the fracture behaviour of the weldbonded joints.

Section: Grades Of Advanced High Strength Steelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Technology of Weld-Adhesive Joints

Advanced Structured Materials

Weber

2011

“…At the same time, the safety of the passenger cell can possibly be increased. 1,2 The resistance spot weldability of AHSS is well known, [3][4][5] and the welding parameters can be chosen in a way to obtain welding current ranges for the materials, even with zinc coating, 6 which are wide enough to guarantee sufficiently high process reliability. However, the complex microstructure 7 and the greater springback behaviour 8 of AHSS eventually lead to weld discontinuities, 9 whose probable impact on the static strength of joined components has recently been studied.…”

Section: Introductionmentioning

confidence: 99%

“…Application of AHSS materials for resistance spot welded components helps saving costs and conserving resources due to the higher mechanical strength of AHSS. At the same time, the safety of the passenger cell can possibly be increased 1, 2. The resistance spot weldability of AHSS is well known,3 – 5 and the welding parameters can be chosen in a way to obtain welding current ranges for the materials, even with zinc coating,6 which are wide enough to guarantee sufficiently high process reliability.…”

Section: Introductionmentioning

confidence: 99%

Influence of HAZ cracks on fatigue resistance of resistance spot welded joints made of advanced high strength steels

Science and Technology of Welding and Joining

Weber

Rethmeier

2011

A method is reported with which heat affected zone (HAZ) cracks in a specific region of spot welded joints, made of advanced high strength steels, could be realised. The influence of HAZ cracks on the fatigue behaviour, which is the focus of the contribution, was studied by evaluating the stiffness characteristics as a function of the number of cycles N in comparison with crack-free specimens, i.e. by analysing HAZ and fatigue cracks on the specimen surface and the surface of fatigue fractures containing beach marks. It was found that the fatigue cracks are not initiated at the HAZ cracks. The number of cycles to failure N f is not significantly reduced for specimens with HAZ cracks. Overall, the examinations did not reveal any influence of HAZ cracks on the fatigue strength of resistance spot welded joints.

“…Newly developed super high strength steels, also called advanced high strength steels (AHSS) and ultra high strength steels (UHSS), play an important key role for the further development of lightweight steel autobodies [1,2]. The higher mechanical strengths of those steel grades are strongly needed to improve the safety of the passenger cell with -at the same time -more or less constant weight of the body-in-white in particular and of the overall vehicle in general.…”

Section: Introductionmentioning

confidence: 99%

Resistance spot welding and weldbonding of advanced high strength steels

Weber¹,

Thommes

Materialwissenschaft Werkst

et al. 2010

The resistance spot welding procedure is one of the most important joining techniques in lightweight car body shell mass production. Especially for newly developed high strength multiphase steels, also called advanced high strength steels (AHSS), and ultra high strength steels (UHSS), this joining technique has more advantages than other thermal and mechanical joining procedures for thin steel sheets. Additionally, the technique of adhesive bonding and its combination with the technique of resistance spot welding called weldbonding becomes more and more important. One of the targets of the contribution is to show the influence of joined advanced high strength steels on the process reliability for both the resistance spot welding process and the weldbonding process. Based on welding current ranges and on results of electrode wear tests, statements concerning the resistance spot weldability of some special AHSS will be given. The mechanical behaviour of spot welded and weldbonded joints for different AHSS will be studied. Furthermore, some statements regarding the fracture behaviour, the hardness and the fatigue behaviour of both spot welded and weldbonded joints for different AHSS will be given. Finally, some results on the mechanical properties of spot welded and weldbounded joints under corrosive attacks with be discused.