Determination of mechanical properties of the weld zone of tailor-welded blanks

• Autorzy: Rojek J. , Hyrcza-Michalska M. , Bokota A. , Piekarska W.

Warianty tytułu

PL

Wyznaczanie własności mechanicznych strefy spoiny w blachach spawanych laserowo

• Języki publikacji: EN

Abstrakty

EN

The basic factor influencing the formability of tailor welded blanks (TWB) is hardening of the weld zone (consisting of fusion and heat-affected zones) during welding process [1]. This reduces formability in the area of weld and it has been identified as the basic factor that should be taken into account in the tailored blank model. Accurate modelling of tailor welded blanks requires knowledge of mechanical properties of material in the weld zone. Determination of mechanical characteristics of the weld zone in TWB is not an easy task because of small extension of this zone. The article will present differ-ent methods available to obtain data necessary for TWB forming simulation. The following methods have been used to determine the extension and mechani-cal parameters of the weld and heat affected zone: ? Metallographic observations ? provide information about the extension of the fusion and heat-affected zones, as well as phase composition in these zones. ? Uniaxial tension tests ? these tests give stress-strain relationships for the par-ent and weld material. ? Microhardness test ? these tests provide information about the distribution of hardness in the tailor weld blank, this indicates the extension of the weld zone, the relationship between hardness and strength of the material allows us to determine strength parameters of the weld zone. ? Indentation tests. The results of these tests combined with inverse numerical analysis allow us to determine mechanical properties of both parent material and weld zone. ? Numerical simulation of laser welding. This is an alternative procedure to de-termine the geometry and mechanical properties of the weld zone, which is based on simulation of the welding process using the thermo-mechano-metallurgical model. Phase fraction distributions after welding are obtained. Knowing the mechanical properties of each phase and using the rule of mixtures the effective yield stress of the material in the weld zone is calculated. Results obtained with different methods have been compared showing generally a good agreement of the compared results. This will be helpful in choosing the most suitable method for practical TWB forming modelling. ACKNOWLEDGMENT Authors acknowledge funding by the EC research project SIM-TWB: Accurate Simulation of Tai-lor-Welded-Blanks to Reduce Process Design Time for The Sheet Pressing Industry (Contract no: 032657).

PL

Artykuł przedstawia różne dostępne metody wyznaczania własności mechanicznych strefy spoiny w blachach spawanych do tłoczenia (ang. TWB - Tailor-Welded Blanks). Przedstawione metody opierają się na badaniach eksperymentalnych jak również łączą próby doświadczalne z analizą numeryczną. Omawiane metody obejmują obserwacje metalograficzne, próby jednoosiowego rozciągania, próby wciskania (indentacji), pomiary mikrotwardości połączone z numeryczną analizą odwrotną oraz numeryczną symulację procesu spawania. Własności mechaniczne materiału w strefie spoiny są wyznaczane w celu określenia parametrów modelu konstytutywnego wykorzystywanego w symulacji kształtowania blachy spawanej laserowo.

Słowa kluczowe

EN

tailor welded blanks; welding; mechanical properties; indentation; simulation

• Wydawca: Wydawnictwa AGH
• Czasopismo: Computer Methods in Materials Science
• Rocznik: 2009
• Tom: Vol. 9, No. 1
• Strony: 153--158
• Opis fizyczny: Bibliogr. 5 poz., rys.

Twórcy

autor

Rojek J.

autor

Hyrcza-Michalska M.

autor

Bokota A.

autor

Piekarska W.

• Institute of Fundamental Technological Research, Warsaw, Poland,

Bibliografia

• 1. Piela, A., Rójek, J., Validation of the results of numerical simulation of deep drawing of tailor welded blanks, Archives of Metallurgy, 48, 2003, 37-51.
• 2. Hyrcza-Michalska, M., Grosman, F., The research of laser welded blanks characteristic in basic and technological drawability tests, Metal Forming Conference 2008, Steel Research International, 79, Special Edition Metal Forming Conf, Vol. l, 2008, 780-787.
• 3. Abdullah, K., Wild, P.M., Jeswiet, J.J., Ghasempoor A., Tensile testing for weld deformation properties in similar gage tailor welded blanks using the rule of mixtures, Journal of Materials Processing Technology, 112, 2001, 91-97.
• 4. Bokota,  A.,  Domański,  T., Numerical  analysis of thermomechanical phenomena of hardening process of elements madę of carbon steel C80U, Archives of Metallurgy and Materials, 52, 2007, 277-288.
• 5. Piekarska, W., Numerical analysis of thermomechanical phenomena  in   a  welding  process,   Habilitation   Thesis, Politechnika Częstochowska, 2008 (in Polish).