Covers the determination of the resistance of metallic materials to scratching abrasion by means of the dry sand/rubber wheel test.
The Koehler K93300 Dry Abrasion Tester uses a rubber-rimmed wheel as the bed for silica abrasive that is fed from a hopper by a nozzle between the sample and the wheel. The sample is pressed into the wheel by a dead weight loaded lever. The test is run for a set number of revolutions with automatic cutoff and the wear is measured by measuring the volume of material lost through mass loss and density measurements. The flow of sand into the gap between the surfaces is controlled by the geometry of the nozzle that must be very carefully defined to obtain the required sand flow rate. The abrasive only passes through the wear interface once and is thrown away at the end of the test. The uniform loading and uniform flow of abrasive into the gap between wheel and the specimen under controlled conditions give consistent results. The properties of the rubber lining of the wheel also have a major effect on the results and need to be carefully controlled.
Conforms to the specifications of:
Abrasive: AFS 50 to 70 test sand (about 200 micron size)
Wheel Speed: 200 rpm
Abrasive Flow Rate: 300 to 400 gms/min
Test Load: 45 to 130 N
Wheel Diameter: 228 mm
Chlorobutyl Rubber Hardness: A 58 to 62 on a Shore Durometer
Revolution Controller: Microprocessor based digital preset counter 1 rev to 9999 revs