ISO 22731:2020 pdf download.Carbonaceous materials used in the production of aluminium — Cathode — Cathode abrasion testing
1 Scope
This document specifies a method for the determination of the resistance to physical abrasion of a cathode sample.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 8007-1, Carbonaceous materials used in the production of aluminium — Sampling plans and sampling
from individual units — Part 1: Cathode blocks
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Principle
A cathode core sample is placed in a grinding or polishing apparatus equipped with abrasive paper for 30 s or 60 s, depending on the cathode grade. The opposite direction of rotation of the head and the base of the apparatus causes the sample to be abraded. The height of the sample is measured before and after the test and then the abrasion is calculated from the loss of sample height. The result is given in per cent.
5 Apparatus
5.1 Caliper, with a measuring range of 0 mm to 150 mm and an accuracy of 20 µm for dimensions ≤ 100 mm.
5.2 Grinding or polishing apparatus, equipped with a sample holder and a powerhead. It should be capable of maintaining the abrasive disc speed at 200 rpm and the head speed at 100 rpm. The head force applied on each sample is 50 N.
5.3 Abrasive disc, silicon carbide SiC type, grit size 60.
6 Sampling
Sample the cathode blocks in accordance with ISO 8007-1. In order to achieve representative test results, a core sample with diameter (50 ± 0,2) mm and length (20 ± 0,2) mm shall be taken.
7 Procedure
— Measure the core height, rounded to the nearest 0,01 mm.
— Set the speed of the abrasive disc to 200 rpm, the speed of the head to 100 rpm and the pressure applied on the sample to 50 N.
— Place the core sample in the sample holder and start the abrasion test. The total test duration should be set at 30 s for 100 % graphite and graphitized grades and at 60 s for all other samples.
— Measure the sample height after grinding.
ISO 22731:2020 pdf download
