BS ISO 18515 pdf download Carbonaceous materials for the production of aluminium — Cathode blocks and baked anodes — Determination of compressive strength
Note 2 to entry: The compressive strength is expressed in Mega Pascal (MPa)
Note 3 to entry: Generally, the maximum force displayed on the test machine and the force at fracture is similar,if they are different, the term refers to the maximum force displayed.
The compressive strength is determined using cylindrical or cubic test specimens. A test specimen withplane parallel end planes is pressed between the pressure plates of a testing machine. The compressivestrength is calculated from the maximum force and the initial cross-section of the test specimen.
51Compression-testing machine, which meets at least the demands of class 2, in accordance withIS0 7500-1.
5.2 Measuring device, with two pressure plates.
The device shall ensure a uniform load over the surface by cardanic suspension.
5.3Measuring device(e.g. vernier calliper, in accordance with ISO 13385-1), capable of measuring thelinear dimensions of the test specimens with an accuracy of +0,5.
Sampling and sample preparation6.1
Sampling shall be in accordance with the appropriate method, i.e. ISO 8007-1,ISO 8007-2, ISO 8007-3, orbe agreed with the applicant. The number ofspecimens shall be defined with respect to the homogeneityof the material to be tested.
Cylindrical cubic test specimens ofany size can be used, subject only to the requirement that the smallestdimension shall be atleast three times the diameter ofthe largest structural constituent (e.g. maximumgrain size) ofthe material to be tested, but not smaller than 5 mm. When cylindrical test specimens areused, their height shall be equal to the diameter (isometrical cylinders). Similarly, when using hollowcylinders, the height shall be equal to the outer diameter
7.1Perform all measurements at room temperature, i.e. in the range 10 °C to 35 °C.
7.2Choose the measuring range of the testing machine, such that the expected maximum force is atleast 1/10 of full scale. Centre the test specimen on the support.
Increase the force uniformly and shock-free at a rate (velocity of the force bearing) of about 5 mm/minuntil the test specimen fractures. Determine the maximum force.