Wear index

TWI = Taber Wear Index. CS-10 abraser wheels, 100 gram load, determined as average weight loss per 1000 cycles for total test of 6000 cycles. 

At the end of each interval the average scar diameter is recorded. Two values are generally reported— load wear index (formerly mean Hertz load) and weld point. 

Taber wear index The ability of a material to withstand mechanical action such as rubbing, scraping, or abrasion that tends to progressively remove... 

From this test, antiwear and extreme-pressure data were determined, such as welding load, load wear index and wear scar diameter under a load of 40 decanewtons (daN), 60 daN and 80 daN, respectively. First, evaluations were performed on the three original nonmodified hard-core RMs, then evaluations were performed on the sulfur-functionalized ones. Four-ball test data (results only for one concentration 10 wt% additive) are summarized in Table 3.9 (Delfort et al., 1995 and 1999) for ... 

Modified hard-core RMs by phosphosulfurized compound. Improved extreme-pressure and antiwear properties have also been obtained with the introduction of some chemical species, such as sulfur, phosphorus or boron derivatives, into the colloidal core (Delfort et al., 1998 Inoue, 1993 Inoue and Nose, 1987). Welding loads, load wear index and wear scar diameter at 5 wt% of a CaC03 core surrounded by a calcium alkylaryl-sulfonate surfactant shell, and modified by phosphosulfurized calcium carbonate core were evaluated for calcium dialkyl dithiophosphate (CaDTP) and calcium trithiophosphate (CaTTP) with the four-ball extreme-pressure test (ASTM D2783 standard method). Both modified products exhibit improved extreme-pressure performances (welding load and load wear index), while their antiwear properties (wear scar diameter) compared to those of the original micellar substrate remain at least at the same level. 

Welding loads and load wear index at 5 wt% concentration (as the extreme pressure performances) are improved compared to those of the original non-phosphosulfurized substrate (Delfort et al., 1998). The welding load (daN), wear load index (daN) and wear scar diameters (mm) under a load 60 daN behavior are... 

Medium Welding load (daN) Load wear index (daN) Wear scar diameter (mm)... 

Test which is used to determine the relative wear-ball preventing properties of lubricants under boundary test lubrication conditions. Two values are reported - load wear index and weld point from two procedures EP test ASTM D 2596 and wear test ASTM D2266. There are four steel /2-inch balls. Three of the balls are held together in a cup filled with lubricant while the fourth ball is rotated against them. Resistance to motion. 

When tested in the four-ball machine, solutions of sulfur in petroleum oils of moderate viscosity or in white oil raise the critical load for the onset of severe, destructive wear, which is designated as "antiseizure" action in the technological idiom of the four-ball test. Davey [54] found a significant increase in the critical initial seizure load from 834 N (85 kg) for a petroleum base oil to 1275 N (130 kg) for elemental sulfur dissolved in the oil. Sakurai and Sato [55] observed a 3.2-fold increase in the load-wear index (mean Hertz load) for a 0.5 weight-percent solution of elemental sulfur relative to that of the uncompounded white oil. The load-wear index is a specialized result of the four-ball test that can be taken as indicative of the average antiseizure behavior of the lubricant. Mould, Silver and Syrett [56] reported a load-wear index ratio of 3.08 for 0.48% sulfur in white oil relative to that of the solvent oil, and also an increase in the initial seizure load from 441 N to 637 N (45 kg to 65 kg) and in the 2.5-second seizure-delay load from 490 N to 833 N (50 kg to 90 kg). 

Abrasion resistance is usually measured by the Taber Test procedure described by ASTM D1044. Abrasion resistance of unfilled semicrystalline polymers is linked to the degree of crystallinity that is itself related to the molecular stmcture and weight of the resin and its processing. Table 3.54 includes the results of testing two types of perfluoroalkoxy polymers, PFA and MFA, and ECTFE. Notice the large difference between wear index (weight loss by abrasion in 1000 cycles) of ECTFE which is a partially... 

The results of an abrasion test (ASTM D4060-01) carried out for 500 test cycles are presented in Table 11.4. Wear index decreased monotonically with the increase in the HDDA content in the coating formulation, which showed that the abrasion resistance property of BDGDA improved in the presence of HDDA. Improvement in abrasion resistance of the coating with increase in HDDA content is attributed to the increase in the cross-link density on addition of HDDA. 

Sample (BDGDA) (HDDA) (Wear Index) Hardness Hardness... 

Wear index In abrasion resistance tests using the Taber Abraser, it is the loss in weight in milhgram per 1,000 cycles of abrasion under a specific set of test conditions (Federal Standard 141a, Method 6192). 

As would be expected, the mercaptosilane increases the modulus and tensile to values comparable to those of the carbon black compound. In the Goodrich flexometer test, the heat buildup, which is known to be a rather severe problem, is 27°C, which is well below the value obtained with caibon black. The mercaptosilane also improves the compression set and the Pico Abrasion Index. Significantly, the Road Wear Index was improved to give equivalency to the carbon black compound. 

A model has been developed to predict the wear of railway wheels. The wear modelling approach is based on a wear index commonly used in rail wear predictions. This assumes wear is proportional to Ty, where T is tractive force and y is slip at the wheel/rail interface. Twin disc testing of rail and wheel materials was carried out to generate wear coefficients for use in the model. 

The approach used in the model for predicting wear is based on a rail wear index [2]. An energy approach is adopted in the analysis of the relationship between wear rate and contact conditions. This assumes that wear rate ( xg/m rolled/mm contact area) is related to work done at the wheel/rail contact (wear rate = KT A, where T is tractive force and / is slip at the wheel/rail interface, K is a wear coefficient and A is the contact area). 

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