Wear rate steel disk, effect

The long-chain structure by itself, as exemplified by n-aliphatic hydrocarbons, shows no extreme-pressure lubricant functionality. Evidently the additive action is connected with the carboxylate ester and the sulfide structures. To demonstrate this, Dorinson isolated an ester/ sulfide component from sulfurized methyl undecylenate, identified its structure, synthesized an organosulfide-ester with this structure, and showed that the lubricant additive activity was the same for the fraction separated from sulfurized methyl undecylenate end for the synthetic material. The data, summarized ib Fig. 11-15, were obtained tiy pin-and-disk wear tests with hardened steel rubbing specimens and show the effect of contact pressure on the depth-rate of wear. The significant feature is the change from a low rate of wear, relatively insensitive to increase of pressure in the range 0.276-1.724 GPa (40,000-250,000 Ib/in ), to pressure-sensitive increase of wear rate at 1.724 GPa and higher. 

In order to study the effect of the degree of crystallinity on friction and wear of PET, the friction measurements in which the steel sphere was slid on flat PET surfaces were carried out. Measurements of the friction and wear rate were also made on the PET pins sliding against a smooth steel surface at a speed 0.1 m/s under a load 10 N by means of a pin-on-disk type apparatus. The PET specimens of four different crystallinity (8, 39, 55 and 75 % ) were used in the present work. The specimen of the lowest crystallinity had a structure similar to an amorphous polymer, while two specimens of crystallinity, 39 % and 55 % had a spherulite-like structure. The highest crystallinity had a fiber-like structure. Conclusions obtained are as follows ... 

Fig. 11. The effect of fiber addition on the specific wear rates of a few polymers (2). The rectangular bar chart indicates specific wear rate (units on the left of the graph) and vertical arrows indicate the coefficient of friction (units on the right of the graph). Test conditions are (i) 440°C steel ball (dia. = 9 mm) sliding on polymer specimen, Normal load = 5 N, y = 0.1 m/s, roughness of polymer surface = 400 nm, 30% humidity (72) (ii) test conditions same as for (i) (72) (iii) test conditions same as for (i) (72) (iv) reciprocating-pin-steel plate apparatus, counterface roughness Eg, = 0.051 ixm, N2 environment, (73) (v)) test conditions same as for (iv) (73) (vi) pin-on-steel (AISI02 quench hardened) disk apparatus, counterface roughness = 0.11 um, p = 0.66 MPa, y = 1 m/s (29) (vii) test conditions same as for (vi) (29) (viii) test conditions same as for (vi) (29). Reprinted from Ref. 2.

Fig. 13. The effect of fiber and soft phase addition on the specific wear rates of PTFE (2). The rectangular bar chart indicates specific wear rate (units on the left of the graph) and vertical arrows indicate the coefficient of friction (units on the right of the graph). Test conditions pin-on-steel disk apparatus, counterface roughness i a = 2.8 /itm, p = 3.14 MPa, V — 0.5 m/s, T = 23°C, (Data are taken from Ref. 11). Reprinted from Ref. 2.

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