SÜRTÜNME KARIŞTIRMA KAYNAĞI İLE BİRLEŞTİRİLMİŞ BAĞLANTILARDA PİM ÇAKIŞMASININ MEKANİK ÖZELLİKLER ÜZERİNE ETKİSİ

Öz

Bu çalışmada, AA-7075 T651 alüminyum alaşımlı plakaların sabit bir pim ofset mesafesi ve iki farklı ofset yönü ile üst üste bindirilmiş iki kaynak dikişi için mekanik özelliklerindeki değişimler araştırılmıştır. Herhangi bir ofset olmaksızın plakaların temas yüzeyinde gerçekleştirilen tek kaynak dikişinin mekanik özellikleri ile karşılaştırma yapılmıştır. Ayrıca kaynaklı bağlantılar için mikroyapısal incelemeler yapılarak kaynaklı bağlantılardaki kusurlar ve pim karıştırma bölgesine ait tane yapısındaki değişimler araştırılmıştır. Deneysel verilerin değerlendirilmesi sonucunda en yüksek çekme mukavemeti olan 423 MPa, 400 dev/dak takım dönme hızında ve herhangi bir çakışmanın olmadığı tek kaynak dikişine sahip kaynaklı bağlantıdan elde edilmiştir. Bu koşul için ölçülen birim uzama %10 iken, en yüksek birim uzama değeri %12,5, 400 dev/dak ve pim ofset yönü olarak pimin dönüş yönünün seçildiği kaynaklı bağlantıdan elde edilmiştir. En yüksek mukavemet ve birim uzama (%) değeri üç farklı pim ofset yönü için de takım dönme hızının 400 dev/dak olduğu durumda elde edilmiştir. Takım dönme hızındaki artış ile çekme dayanımında ve birim uzama (%) değerinde azalma meydana geldiği ortaya çıkmıştır.

Anahtar Kelimeler

• Sürtünme karıştırma kaynağı,pim çakışması,mekanik özellikler,mikroyapı

EFFECT OF PIN OVERLAP ON MECHANICAL PROPERTIES OF FRICTION STIR WELDED JOINTS

Abstract

In this study, the changes in mechanical properties of AA-7075 T651 aluminum alloy plates for a fixed pin offset distance and two overlapping weld seams with two different offset directions were investigated. Comparisons were made with the mechanical properties of the single weld seam formed on the contact surface of the plates without any offset. In addition, microstructural observations of welded joints were carried out to investigate the defects in welded joints and the changes of grain structure in the nugget zone. As a result of evaluation of the experimental data, the highest tensile strength, 423 MPa, was obtained from the welded joint with single weld seam which was manufactured with a tool rotational speed of 400 rpm and without any pin overlap. The elongation at rupture for this condition was measured to be 10%, while the highest elongation at rupture, 12.5%, was obtained from the joint welded with a tool rotational speed of 400 rpm and where AS was selected as the pin offset direction. The highest strength and elongation at rupture (%) for all three different pin offset directions were obtained with the tool rotational speed of 400 rpm. It was revealed that with the increase in tool rotational speed, both tensile strength and elongation at rupture (%) decreased.

Keywords

• Friction stir welding,pin overlap,mechanical properties,microstructure

Kaynakça

1. [1] Sharma, C., Dwivedi, D. K., Kumar, P., “Effect of welding parameters on microstructure and mechanical properties of friction stir welded joints of AA7039 aluminum alloy”, Materials & Design, 36, 379-390, 2012.
2. [2] Venkateswarlu, G., Davidson, M., Tagore, G., “Influence of process parameters on the cup drawing of aluminium 7075 sheet”, International Journal of Engineering, Science and Technology, 2, 41-49, 2010.
3. [3] Mao, Y., Ke, L., Liu, F., Huang, C., Chen, Y., Liu, Q., “Effect of welding parameters on microstructure and mechanical properties of friction stir welded joints of 2060 aluminum lithium alloy”, The International Journal of Advanced Manufacturing Technology, 81, 1419-1431, 2015.
4. [4] Hasan, M. M., Ishak, M., Rejab, M. R. M., “Effect of backing material and clamping system on the tensile strength of dissimilar AA7075-AA2024 friction stir welds”, The International Journal of Advanced Manufacturing Technology, 91, 3991-4007, 2017.
5. [5] Xu, W. F., Li, Z. X., Sun, X. H., “Effect of Welding Speed on Mechanical Properties and the Strain-Hardening Behavior of Friction Stir Welded 7075 Aluminum Alloy Joints”, Journal of Materials Engineering and Performance, 26, 1938-1946, 2017.
6. [6] Zhou, L., Li, G. H., Liu, C. L., Wang, J., Huang, Y. X., Feng, J. C., Meng, F. X., “Effect of rotation speed on microstructure and mechanical properties of self-reacting friction stir welded Al-Mg-Si alloy”, The International Journal of Advanced Manufacturing Technology, 89, 3509-3516, 2017.
7. [7] Golezani, A. S., Barenji, R. V., Heidarzadeh, A., Pouraliakbar, H., “Elucidating of tool rotational speed in friction stir welding of 7020-T6 aluminum alloy”, The International Journal of Advanced Manufacturing Technology, 81, 1155-1164, 2015.
8. [8] Mohammadzadeh Jamalian, H., Farahani, M., Besharati Givi, M. K., Aghaei Vafaei, M., “Study on the effects of friction stir welding process parameters on the microstructure and mechanical properties of 5086-H34 aluminum welded joints”, The International Journal of Advanced Manufacturing Technology, 83, 611-621, 2016.

9. [9] Daniolos, N. M., Pantelis, D. I., “Microstructural and mechanical properties of dissimilar friction stir welds between AA6082-T6 and AA7075-T651”, Int. J. Adv. Manuf. Technol., 88, 2497-2505, 2017.
10. [10] Dehghani, K., Ghorbani, R., Soltanipoor, A. R., “Microstructural evolution and mechanical properties during the friction stir welding of 7075-O aluminum alloy”, Int. J. Adv. Manuf. Technol., 77, 1671-1679, 2015.
11. [11] Mao, Y. Q., Ke, L. M., Chen, Y. H., Liu, F. C., Xing, L., “Improving local and global mechanical properties of friction stir welded thick AA7075-T6 joints by optimizing pin-tip profile”, Int. J. Adv. Manuf. Technol., 88, 1863-1875, 2017.
12. [12] Palanivel, R., Koshy Mathews, P., Murugan, N., Dinaharan, I., “Effect of tool rotational speed and pin profile on microstructure and tensile strength of dissimilar friction stir welded AA5083-H111 and AA6351-T6 aluminum alloys”, Materials & Design, 40, 7-16, 2012.
13. [13] Mishra, R. S., Ma, Z. Y., “Friction stir welding and processing”, Materials Science and Engineering: R: Reports, 50, 1-78, 2005.
14. [14] Sundaram, N. S., Murugan, N., “Dependence of ultimate tensile strength of friction stir welded AA2024-T6 aluminium alloy on friction stir welding process parameters”, Mechanics, 78, 17-24, 2009.
15. [15] Peel, M., Steuwer, A., Preuss, M., Withers, P. J., “Microstructure, mechanical properties and residual stresses as a function of welding speed in aluminium AA5083 friction stir welds”, Acta Materialia 51, 4791-4801, 2003.
16. [16] Gemme, F., Verreman, Y., Dubourg, L., Wanjara, P., “Effect of welding parameters on microstructure and mechanical properties of AA7075-T6 friction stir welded joints”, Fatigue Fract. Eng. Mater. Struct., 34, 877-886, 2011.
17. [17] Franchim, A. S., Fernandez, F. F., Travessa, D. N., “Microstructural aspects and mechanical properties of friction stir welded AA2024-T3 aluminium alloy sheet”, Materials & Design, 32, 4684-4688, 2011.
18. [18] ASTM. Standard Test Methods for Tension Testing of Metallic Materials, ASTM International, West Conshohocken, PA, 2016, www.astm.org.
19. [19] Gupta, R. K., Das, H., Pal, T. K., “Influence of Processing Parameters on Induced Energy, Mechanical and Corrosion Properties of FSW Butt Joint of 7475 AA”, Journal of Materials Engineering and Performance, 21, 1645-1654, 2012.
20. [20] Karthikeyan, L., Senthil Kumar, V. S., “Relationship between process parameters and mechanical properties of friction stir processed AA6063-T6 aluminum alloy”, Materials & Design, 32, 3085-3091, 2011.