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The ultrasonic testing of the spot welded different steel sheets

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Języki publikacji
EN
Abstrakty
EN
Purpose: Purpose of this paper is to investigate the applicability of spot welded different steel sheets to ultrasonic testing, because resistance spot welding of the steel sheets is widely used in the car bodies and transport fields and ultrasonic testing is a good way to evaluate the fatique life of the spot welds. Design/methodology/approach: Methodology of this paper is that two different steel sheets (AISI 304 type austenitic stainless steel sheet and Galvanized steel sheet ) were welded to each other by using resistance spot welding. Some pre-welding tests were made to obtain suitable and optimum weld nugget diameter; and the welding current vs. nugget diameter curve were obtained. By using this curve and kepting constant welding parameters such as current, electrode pressure, weld time, etch., fully identical four spot welded specimens having 5 mm (±0.2) nugget diameter were obtained. The specimens and nugget diameters were tested by using a special ultrasonic test apparatus which is designed for spot welded joints. Findings: Findings are that after the first ultrasonic tests, the four identical spot welded sheets which have AISI 304 - Galvanized steel sheet combination were subjected to the fatigue test in four different number of cycles. There is no any rupture or fracture in spot welded joints after fatigue tests. The spot welded specimens subjected to fatigue test were tested in ultrasonic test apparatus to observe the variation in the weld nugget and joint. The ultrasonic test results before fatigue and after fatigue were compared with each other; and the decreasing of the weld nugget diameter were observed while increasing the number of cycles. The results were shown in figures and discussed. Research limitations/implications: Spot welding of different steel sheets forms different microstructures which respond different values to ultrasonic testing. Evaluation of these responses are quiet difficult. Practical implications: Only a few spot welds can be evaluated among approximately 4 thousands of spot welds on a car body. Only selected spot welds can be ultrasonically tested. Originality/value: Resistance spot welding of AISI 304 and galvanized steel forms austenitic, martensitic and ferritic microstrucutre in the same weld region. Ultrasonic testing of austenitic microstructures is different than the other microstructures. In this study the response of different microstructures to ultrasonic waves are investigated.
Rocznik
Strony
247--250
Opis fizyczny
Bibliogr. 9 poz., rys., wykr.
Twórcy
autor
  • Mechanical Engineering Faculty, Istanbul Technical University, 34437, Istanbul, Turkey
autor
  • Mechanical Engineering Faculty, Istanbul Technical University, 34437, Istanbul, Turkey
Bibliografia
  • [1] M.Vural, A. Akkus On the resistance spot weldability of galvanized interstitial free steel sheets with austenitic stainless steel sheets, Journal of Material Processing Technology, Vol. 153-154 C, pp 1-6, 2004.
  • [2] S. Stancu-Niederkorn, U. Engel and M. Geiger, Ultrasonic investigation of friction mechanism in metal forming, Journal of Materials Processing Technology, Volume 45, Issues 1-4, September,1996.
  • [3] David N. Collins and W. Alcheikh, Ultrasonic non-destructive evaluation of the matrix structure and the graphite shape in cast iron Journal of Materials Processing Technology, Volume 55, Issue 2, 15 November, Pages 85-90, 1995.
  • [4] J. Moysan, A. Apfel, G. Corneloup and B. Chassignole, Modelling the grain orientation of austenitic stainless steel multipass welds to improve ultrasonic assessment of structural integrity International Journal of Pressure Vessels and Piping, Volume 80, Issue 2, February, Pages 77-85, 2003.
  • [5] H. Yoneyama, S. Shibata and M. Kishigami, Ultrasonic testing of austenitic stainless steel welds False indications and the cause of their occurrence NDT International, Volume 11, Issue 1, February 1978.
  • [6] F. Ammirato and R. ShankarX. Edelmann Ultrasonic examination of dissimilar-metal welds in BWR and PWR plants International Journal of Pressure Vessels and Piping, Volume 35, Issues 1-4, Pages 37-56, 1988.
  • [7] N. R. Joshi, Exploration of heterogeneous duplex grain structure in type 304 austenitic stainless steel using ultrasonic spectroscopy Ultrasonics, Volume 17, Issue 5, September 1979, Pages 205-208, 1979.
  • [8] P. Kemnitz, U. Richter and H. Klüber, Measurements of the acoustic field on austenitic welds: a way to higher reliability in ultrasonic tests, Nuclear Engineering and Design, Volume 174, Issue 3, Pages 259-272, 5 October 1997.
  • [9] G. P. Singh and R. C. Manning’ Discrimination of ultrasonic indications from austenitic stainless-steel pipe welds NDT International, Volume 16, Issue 6, December 1983, Pages 325-.329
Typ dokumentu
Bibliografia
Identyfikator YADDA
bwmeta1.element.baztech-f65aad31-61d1-490f-960c-4479c9cdd1d4
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