Standard Test Method for Ranking Resistance of Materials to Sliding Wear

in Block-on-Ring Wear Test Using Micro-Tribometer mod. UMT-2

ASTM G77-98

Summary of Test Method:

This test method covers the procedure for determining sliding wear of various materials using the block-on-ring geometry. A stationary block specimen is pressed with a constant force against a rotating ring specimen at 90º to the ring’s axis of rotation. Friction between the sliding surfaces of the block and ring results in loss of material from both pieces.  Many materials can be fabricated into blocks and rings, however the standard’s emphasis is on metals. The test may be run at the loads, velocities, and temperatures which simulate the service conditions with various lubricants and liquids. The standard does not specify test parameters such as rpm, load, or test duration, but lists typical parameters:

Ring dimensions – 35 mm dia. x 8.7 mm width

Block dimensions – 6.35 mm x 10.2 mm x 15.8 mm

Normal load  – 134 N

Velocity  – 180 rpm

Duration – 30 min.

Wear test results are reported as the volume loss in cubic millimeters for both the block and ring. . The UMT-2 can additionally measure in-situ (during the test) dynamic wear depth, friction force and coefficient. The following is a typical test setup.

UMT Hardware Configuration:

·         4” Mounting Block – PN M30C116

·         Model DFH-20 Dual Friction/Load Sensor

-  range 2 to 200 N

·         Upper Specimen Holder for Blocks

-   for sensors mod. DFH

·         Suspension with Linear Guide

·         Upper Specimen Test Block

·         Lower Block-on-Ring Drive

. BHHM

·         Lower Specimen Test Ring

·         Optional Additional Sensors

 - mod. AE-5 Contact Acoustic Emission Detector

 - mod. TMR-150 Temperature Measurement & Recording

 - mod. RTD Temperature Sensor

UMT Software Test Setup:

UMT Options File:

Load the options file which contains settings for the block-on-ring drive and the 100 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 134 N Constant Force for a Duration of 10 sec.

     Spindle  – Velocity is 0 revs/min.

     Slider     – is idle.

Sheet 2 is the wear-life test period

     Carriage - applies a 134kg Constant Force for a Duration of  30 min. or as needed to achieve significant wear.

     Spindle   – Velocity is 180 revs/min, Move-Continuous,  and Direction- Counterclockwise

     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)

    AE input – Acoustic Emission (optional)

    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.