Determination of Slurry Abrasivity (Miller Number) and Slurry Abrasion Response of Materials (SAR Number) using Micro-Tribometer mod.

ASTM G75-95

Summary of Test Method:

The relative effect of slurry abrasivity in both the Miller Number and the SAR Number is determined by measuring the mass loss rate of a standard-shaped carbon-iron metal block when lapped in slurry. The block is held by a constant force against a neoprene sheet that is mounted in a tray containing the slurry. The neoprene sheet acts as a lap. The tray is driven in a linear reciprocating motion, which  keeps fresh slurry flowing under the block. The test is run for 6 hours in 2 hour increments with mass loss being measured at the end of each 2 hour increment. The 3 measurements are used to determine the wear curve. The slope of the curve at the end of  the first 2 hours is used to calculate the Miller number. The SAR Number is obtained by multiplying the Miller Number by the ratio of the standard wear block material’s specific gravity  to the Specific Gravity of the specimen material.

UMT Hardware Configuration:

·         4” Mounting Block – PN M30C116

·         2” Mounting Block – PN M30C166

·         Model DFH-5 Dual Friction/Load Sensor

-          range 50 g to 5 kg

·         Self-Adjusting Universal Joint Holder – PNAM30C232A

·         Plastic Holder for Blocks

  - for sensors mod. DFH

·         Test Block

·         Neoprene Lap

·          Plastic Slurry Tray

·         Lower linear Reciprocating Motion Drive

Manually adjust for 1” travel

 -  mod. RMH

·         Optional Additional Sensors

 - mod. TMR-150 Temperature Measurement & Recording

 - mod. RTD Temperature Sensor

Footnote: The standard recommends an 8” stroke at 48 rpm, which fully corresponds to a 1” stroke at 384 rpm on the UMT.

UMT Software Test Setup:

UMT Options File:

Load the options file which contains settings for the Linear Reciprocating Motion drive and the 5 kg force/load sensor.

Test Sequence:

The Test Sequence should consist of 2 sheets.

Sheet 1 is for settling time for the carriage to establish the initial normal load.

     Carriage - applies a 2.224 kg Constant Force for a Duration of 10 sec.

     Spindle  – Velocity is 0 revs/min.

     Slider     – is idle.

Sheet 2 is a 4-hr. period

     Carriage - applies a 2.224 kg Constant Force for a Duration of  4 hours.

     Spindle   – Velocity is 192 revs/min, Move-Continuous,  and Direction- Clockwise

     Slider      – is idle.

Data Collection:

The following should be checked under DataFile:

    Fx – Friction Force

    Fz – Normal Force

    T   – Time

    Z1 – Carriage Position (Used to determine Wear Depth)

    Te input – Temperature (optional)

Report:

Use the Viewer program to plot test results.

Select the parameters to be displayed by checking

the appropriate box under Parameters on the Viewer screen.

For viewing COF plots of reciprocating tests check the Fz box, click on the Symmetry button, click on the Peak Detect button, and then check the COF box. 

Multiple test results can be viewed at the same time as in the example below.