PSI - Issue 47

Mario A. Sánchez Miranda et al. / Procedia Structural Integrity 47 (2023) 310–324 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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It was observed during the FSW joining of UHMWPE and PP the generation of small defects inside the welded zone, which were related to blended material introduced between the shoulder and the bearing. The revision of the bearing after tests, leads to corroborate small traces of polymers inside; this effect has been reported in previous investigations [35], nevertheless, this problem was considerably reduced in the present investigation. 3. Experimental results Table 3 contains a list of welding parameters for dissimilar joining UHMWPE-PP, which comprises 20 modalities of testing. The listed parameters are: test modality, rotational speed, advanced speed, penetration speed, pin profile and pre-heating or not pre-heating on testing specimens.

Table 3. Parameters used in FSW for the dissimilar joint of UHMWPE-PP.

Rotational speed (rpm)

Advanced speed (mm/min)

Penetration Speed (mm/min)

Pin Profile

Pre-heating

FSW Modality

1112 1512 2012 2512 3012

1100 1500 2000 2500 3000 1100 1500 2000 2500 3000 1100 1500 2000 2500 3000 1100 1500 2000 2500 3000

12 12 12 12 12 12 12 12 12 12 25 25 25 25 25 25 25 25 25 25

5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5

Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal Hexagonal

Without Without Without Without Without

1112* 1512* 2012* 2512* 3012* 1125 1525 2025 2525 3025 1125* 1525* 2025* 2525* 3025*

With With With With With

Without Without Without Without Without

With With With With With

The test modalities listed in Table 3 are as follows : the first two numbers corresponding to rotational speed, second two number to advanced speed and one asterisk indicates pre-heating. Then, the modality 1112, indicates 1100 rpm of rotation speed, 12 mm/min of transverse speed and without pre-heating. Tests with pre-heating were carried out imposing 80° C for the two welding plates inside a commercial oven, and following the procedure of a previous work [25]. Superficial temperature variation from taking out the preheating material in the oven to beginning the FSW process, was lower than 6° C, measured with a laser temperature sensor. In order to validate the resulting mechanical properties, tensile tests were performed in joined UHMWPE-PP specimens; Figure 6a presents the dimensions of tensile tests specimens, according to international standardization ASTM D638-14; whereas Figure 6b shows a set of tensile specimens after the welding process and machining.