PSI - Issue 13

Miodrag Milčić et al. / Procedia Structural Integrity 13 (2018) 1977 – 1984 Author name / StructuralIntegrity Procedia 00 (2018) 000 – 000

1984

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The equations describing fatigue categories were obtained by linear regression of the bi-logarithmic system. These equations take the form:

a) log(N) = -3,81·ln(  a )+122,9 – for the FSW joints 750/73 b) log(N) = -5,22·ln(  a )+151,2 – for the FSW joints 750/116 c) log(N) = -6,66·ln(  a )+166,5 – for the FSW joints 750/116

4. Conclusions

On the basis of examinations performed, given the results of the experiment and their comparison, the following conclusions can be provided: In this study, friction stir welding of aluminum alloy 2024-T351 was studied by using a vertical milling machine with tool rotation speed n =750 rpm and different welding speeds 73, 116 and 150 mm/min to evaluate the effect of process parameters on the mechanical properties. The minimum frictional heat generated is for the welding parameters is 750/150 rpm/(mm/min) (C-III), and the largest amount of heat for the welding parameters is 750/73 rpm/(mm/min) (A-I). Grain size in SZ is the smallest in the case of the highest welding speed of 750/150 rpm/(mm/min). Joint efficiency as high as 97% of base metal could be achieved at 750/116 rpm/(mm/min). The highest elongation of the welded joint is achieved with the welding parameters 750/116 rpm/(mm/min) and is 7.2%. Profile of distribution and allocation of microhardness depends on the level of temperature and plastic deformation which is highest under the tool shoulder and around the pin. The results show that FSW welded compound achieved with the welding parameters 750/116 has a higher fatigue strength compared to the other two achieved welding parameters 750/73 and 750/150 rpm / (mm / min). This investigation points out that weld joint B-II (welded by 750/116 rpm/(mm/min)) achieves better properties and microstructure than weld joint A-I and C-III (welded by 750/73 and 750/150 rpm/(mm/min)). Thomas W M, Nicholas E D, Needham J C, Murch M G, Temple-Smith P, Dawes C J 1991 Friction stir butt welding , GB Patent No. 9125978.8, International patent application No. PCT/GB92/02203. Gupta R K, Das H, Pal T K 2012 Influence of Processing Parameters on Induced Energy, Mechanical and Corrosion Properties of FSW Butt Joint of 7475 AA, JMEPEG 21, 1645 – 1654 Su J Q, Nelson T W, Mishra R, Mahoney M 2003 Microstructural Investigation of Friction Stir Welded 7050-T651 alloy, Acta Mater., 51, 713 – 729 Ouyang J, Yarrapareddy E, Kovacevic R 2006 Microstructural evolution in the friction stir welded 6061 aluminum alloy (T6-temper condition) to copper, Journal of Materials Processing Technology, 172, 110 – 122. Zimmer S, Langlois L, Laye J, Bigot R 2010 Experimental investigation of the influence of the FSW plunge processing parameters on the maximum generated force and torque, Int J Adv ManufTechnol 47, 201 – 215. Hussain K 2010 Evaluation of parameters of friction stir welding for aluminium AA6351 alloy, International journal of engineering science and technology, vol. 2, no. 10, 5977-5984. Radisavljević I, Živković A, Grabulov V , Radović N 2015 Influence of pin geometry on mechanical and structural properties of butt friction stir welded 2024-T351 aluminum alloy, Hem. Ind. 69 (3), 323 – 330. Perović M, Baloš S, Kozak D, Bajić D , Vuherer T 2017 Influence of kinematic factors of friction stir welding on the characteristics of welded joints of forged plates made of EN AW 7049 a aluminium alloy, Tehnical gazette 24, 3, 723-728. Vidal C, Infantea V, Vilacaa P, 2010 Assessment of Improvement Techniques Effect on FatigueBehaviour of Friction Stir Welded Aerospace Aluminium Alloys, Procedia Engineering 2, 1605 – 1616. Balokhonov R, Romanova V, Batukhtina E, Sergeev M, Emelianova E, 2018 A numerical study of the microscale plastic strain localization in friction stir weld zones, FACTA UNIVERSITATIS Series: Mechanical Engineering Vol. 16, No 1, 77 – 86. References