|DIETERT Foundry Testing Equipment Inc.
9190 Roselawn, Detroit Michigan 48204
Tel: (313) 491-4680
|NO. 875 Friability And Moldability Tester|
|The friability test measures the ability of a compacted molding sand to resist abrasion or scuffing in the first few millimeters at the surface of the mold. Two 2-in. diameter x 2 in. high (50.8 x 0.8 mm) AFS specimens are placed side-by-side in a 7 in. diameter (177.8 mm) cylindrical screen and rotated against one another.
The amount of sand abraded from the specimens after one minute is collected and weighed. The weight of sand removed, divided by the original weight of the specimens and multiplied by 100 is reported as the friability in percent. A friability value above 11% can indicate a tendency to produce dirt defects and loss of casting surface quality.
An adjustable timer controls the test, and the unit includes a collecting pan as well as a brush and coarse screen (to pre-screen the sample), for use in the moldability test. In this test, a 200 g sample of loose sand is placed in the cylindrical screen and rotated for 10 seconds. The weight of sand passing through the screen, divided by two, gives the moldability index of the uncompacted sand.
While the laboratory moldability test has been succeeded by the compactability test for expressing the degree of temper of a molding sand, it is still valuable for monitoring the performance of automatic moldability controllers at the mixers.
Net weight:..................20 lb. (9 kg)