PSI - Issue 39

7

M.A. Sánchez Miranda et al. / Procedia Structural Integrity 39 (2022) 161–172 Author name / Structural Integrity Procedia 00 (2019) 000–000

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In reference [ 22 ] is reported joining efficiency attaining 90% for the four mentioned zones ; whereas fractures observed on specimens of Table 4 were all at the center of weld seam, as shown in Figure 7. In Figure 8 are presented the graphs: tension against displacement, for the parents ABS and PP, using a tensile tests machine with 400 Kg of maximum load and 1.5 mm/min of tensile speed. These results were used to evaluate the joining efficiency of the present dissimilar joint.

Figure 8. Tensile tests in parent specimens of PP and ABS.

Values of UTS on parent materials were: 360 N for PP and 480 N for ABS, as shown in last figure. For tests 3 and 4 in Table 4 and Figure 6, using the UTS of PP, the dissimilar joining efficiencies were as follows: ≈ 91% for test 3, and ≈ 83% for test 4. In order to assess the variation of hardness in the stir zone and its surroundings after FSW of ABS - PP, hardness measures were obtained at this zone. Specimen 13 and 14 in Table 3, with the corresponding welding parameters, were used for the hardness measures. Five hardness indentations along the specimen, each of one indicated with a singular symbol, were obtained with load of 30 gr. and 15 sec of permanence. For each longitudinal position, measures of hardness were performed with 2.5 mm of separation along the specimen width (20 mm), comprising the three zones: ABS, stir zone and PP, as shown in figures 9a and 9b. The last two figures show hardness evolution across the width of specimens for the five longitudinal positions, corresponding to specimens 13 and 14 in Table 3, respectively.