In the production of vehicle bodies, spot welding is widely employed for assembling members made of thin steel sheets. However, since steel sheets for automobiles are approximately 1 mm to 2 mm in thickness, sizes of their spot-welded joints are very small. This makes it impossible to extract the standard-sized specimens (for example, a specimen of a rod of several millimetres in diameter). In this background, the authors have so far developed the tensile test technology for extremely small specimens of below 3 mm in total length and carried out the evaluation of local tensile property of each section of their spot-welded joint. In this paper, the outline of the test technology and the result of the test will be shown first, and then, as an example of the application of the data obtained on strength properties, an introduction will be made of the finite element analysis and fracture strength prediction of spot-welded joints. This paper has introduced the tensile test technology of extra-small specimens and also some examples of experimental results of each section of the spot-welded joint (the base material, the heat-affected zone and the nugget). It also showed, by conducting the finite element analysis of the spot-welded joint in which this strength property data is used, that the joint strength can be predicted with high precision by taking account of kinds of steel used. From now on, by making use of this technology, the authors are planning to design methods for improving strength, such as the development of materials superior in strength at the welded joint. They are hoping that this will contribute to the improvement of strength reliability for automobile bodies. They are also hoping to apply this test technology to not only thin steel sheet spot welding but also to other welding and bonding processes.
Evaluation of local material strength property by small specimen - Application to strength prediction of spot-welded joint
Welding International ; 21 , 4 ; 255-260
2007
6 Seiten, 15 Bilder, 2 Tabellen, 4 Quellen
Aufsatz (Zeitschrift)
Englisch
Punktschweißen , Materialfestigkeit , Prüflingslänge , Vorhersage , Blechdicke , Zugprüfung , Finite-Elemente-Methode , Wärmeeinflusszone , Fahrzeugbaukörper , Betriebssicherheit , Scherprüfung , Schweißlinse , Festigkeitserhöhung , plastische Verformung , Dehnung , Materialbruch , Ermüdungslebensdauer , Stahlblech
Strength of Spot Welded Joint Pairs as Determined by Layout
SAE Technical Papers | 2000
|Prediction of Strength of Spot-Welded Joints by Measurements of Local Mechanical Properties
SAE Technical Papers | 2003
|Strength of spot welded joint pairs as determined by layout
Kraftfahrwesen | 2000
|Torsional Impact Strength of Spot-welded Joints
British Library Conference Proceedings | 2011
|Fatigue strength evaluation of spot-welded joints for car body structures
Tema Archiv | 1987
|