OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 27 No. 2 2025 tribological behaviour of three composite materials ‑ pure PTFE (M1), PTFE with 25 % carbon (M2), and PTFE with 20 % glass fibre (M3) ‑ was investigated as a function of operating parameters such as load, sliding speed, and temperature. The study also aims to evaluate the predictive capability of the proposed numerical model for wear analysis. Materials and Methods Materials The samples were manufactured using compression molding and procured from Innominds Engineering, Pune, Maharashtra. The specimens were machined to a radius of 5 mm and a length of 32 mm using a SimpleTurn 5075 CNC machine procured from ACE Micromatic, Bangalore, India. The actual test specimens are shown in Fig. 1. The PTFE composite properties are given in Table 1. Typically, the volume fraction of carbon in PTFE ranges from 10 % to 30 %, depending on different industrial applications. However, a 25%volume fraction of carbon was considered for the present study, as it provides considerable mechanical reinforcement as well as better stiffness and strength to PTFE [9]. It also avoids agglomeration of the filler, prevents overloading, and provides thermal stability, which improves the wear behavior of the material. Similarly, glass at a 20 % volume fraction in PTFE provides dimensional stability by reducing creep and deformation under load. Furthermore, glass additionally provides chemical stability to PTFE, making it effective for corrosive environments [16]. Ta b l e 1 Properties of PTFE-based composite Properties ASTM Code M1 M2 M3 Density (kg/m3) ASTM D 792 [16] 2,160 2,244 2,147 Tensile Strength (MPa) ASTM D 638 [16] 22.7 15.54 15.8 Compressive Strength (MPa) ASTM D 638 [16] 4.32 15.46 14.32 Shore D Hardness ASTM D 2240 [16] 49 65 61 a b c Fig. 1. Test specimen (a) M1, (b) M2 and (c) M3 Experimental Details Tribological tests were conducted using a pin-on-disc tribometer (Ducom Instruments Pvt. Ltd., Bangalore, India). The operating principle of the setup involves rotating a disc at a constant speed while maintaining a stationary pin pressed against the disc with a specified load. Wear is initiated due to the relative motion between the pin and the disc. The disc is made of austenitic stainless steel (SS 304) with a 165 mm diameter and 8 mm thickness. The average hardness of the plate across the surface was found to be 58 HRC, and the average surface roughness was 1.8 µm. A linear variable differential transducer (LVDT)
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