ISO 20202 pdf download Carbonaceous materials used in the production of aluminium — Cold and tepid ramming pastes — Preparation of baked test pieces and determination of loss on baking
This International Standard describes a method of baking green test specimens made by compactingcarbonaceous ramming pastes. lt includes the baking procedure (heating rate and holding time) and thedetermination of the loss on baking (relative mass loss)
Baked test specimens of ramming paste need to be prepared for the determination of properties after bakingfor instance apparent density, crushing strength and porosity.
2 Normative references
The following referenced documents are indispensable for the application of this document. For datedreferences, only the edition cited applies. For undated references, the latest edition of the referenceddocument (including any amendments) applies.
ISO 4955, Heat-resisting steels and alloys
SO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic methodfor the determination of repeatability and reproducibility of a standard measurement method
ISO 14422, Carbonaceous materials used in the production of aluminium — Cold-ramming pastes 一- Methodsof sampling
ISO 14427, Carbonaceous materials used in the production of aluminium – Cold and tepid rammingpastes — Preparation of unbaked test specimens and determination of apparent density after compaction
ASTM E 220, Standard Test Method for Calibration of Thermocouples by Comparison Techniques
Compacted test specimens of carbonaceous ramming paste are baked in a furnace by raising the temperatureat a specified rate to 1 000 C and holding the temperature at this value for 2 h. The mass of each testspecimen is measured before and after baking and the loss on baking calculated.
4.1Balance, accurate to 0,1 g.
4.2Furnace, e.g. an electrically heated muffle furnace or chamber furnace, with a temperature-controfacility enabling it to meet the requirements qiven in Clause 6.
Keep the furnace at a final temperature of (1 000 ± 10) °C for 2 h to ensure that all the test specimens reach this temperature. Then allow the furnace to cool down to room temperature. Take the test specimens out of the baking container. Remove any packing material which may be sticking to the surface of the test specimens. Determine the mass m 1 of each baked test specimen to 0,1 g.
7 Expression of results Calculate the relative mass loss during the baking process, called the loss on baking, using the following equation:
w is the loss on baking, expressed as a mass fraction in %;
8 Precision (determined in accordance with ISO 5725-2)
Repeatability (r) = 0,9 % (absolute)
Reproducibility (R) = 2,3 % (absolute)
The number of degrees of freedom, i.e. number of laboratories (6) × number of samples (4), was 24.
NOTE The precision will be influenced by variability in the material.
9 Test report
The test report shall include the following information:
a) a reference to this International Standard;
b) all details necessary for identification of the sample tested;
c) the temperature used for preparation of the green test specimens;
d) the results of the test, i.e. the loss on baking;
e) the date of the test;
f) details of any unusual features noted during the determination;
g) details of any operation not included in this International Standard or regarded as optional.