ISO 20202:2004 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.
I Scope
ISO 20202 desaibes a method of baking een test specimens made by compading carbonaceous ramming pastes. It indudes the baking procedure (heating rate and holding time) and the determination of the loss on baking (relative mass loss)
Baked test specimens of ramming paste need to be prepared for the determination of properties after baking, for instance apparent density, crushing strength and porosity.
2 Normative references
The following referenced documents are mdlspensable for the applIcation of this document Far dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (Induding any amendments) applies.
ISO 4955, Heat-resisting stasis and alloys
ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Pail 2: Basic method fog’ the dete,rninetion of repeatability and repioducibuiity ole standard measurement method
ISO 14422, Carbonaceous materials used En the prociticlion of aluminium — Cold-ramming pastes — Methods of samp4’ng
ISO 14427, Carbonaceous materials used in the production of aluminium — Cold and tepid ramming pastes — Preparation of unbaked teat specimens and detemilnetlon of apparent density after compaction
ASTM E 220, Standard Test Method for Calibration of Thermocouples by Comparison Techniques
3 PrInciple
Compacted test specimens at carbonaceous ramming paste are baked In a furnace by raising the temperature at a specified rate to 1 000 C and holding the temperature at this value for 2 h. The mass of each test specimen ie measured before and after baking and the loss on baking calculated.
4 Apparatus
4.1 Balance, accurate to 0,1g.
4.2 Furnace. e.g. an electflcally healed muffle furnace or chamber furnace, with a temperature-control facility enabling II to meet the requirements gtven In Ctause 6.
4.3 BakIng container with covers capable of holding the test specimens and made from heat-resistant steel (e.g. XlSCrNiSi252l steel as specified Ni ISO 4955). The distance between Vie test specimens and between the lest specimens and the container walls shal not be tess than 10mm. An example of a suitable container is shown in Figure 1,
44 Packing material, consisting of elecirographile or calcined petroleum coke, maxrnLsn particle size
1 mm.
4.5 Temperature-measuring device, capable of determining the temperature to withIn ±5 ‘C up to
1 000 ‘C. e.g. a type IC or S thermocouple calibrated Ii accordance with ASTM E 220.
5 Sampling
Sample the paste N, accordance with ISO 14422. Prepare the test specimens in accordance ISO 14427.
6 Procedure
Determine the mass in0 01’ each unbaked test specimen to the neatest 0.1 g.
Insert the test specimens In the baking container (4.3). Surround the lest specimens on all sides by at least 10mm of packing materIal (4.4). Insert the container. with its cover fitted, into the furnace (4.2). Heat the furnace in accordance with the heating programme given in Table 1.
Table I — Heating programme
Temperature range
Heating rate
Initial rate of heating
Root lanwerature to 500 C
(35±5) Cti
‘
Subsequent rate of heatng
500 C ki 1000 C
(100 * 10) C h
-t
Keep the furnace at a final temperature of (1000*10) ‘C for 2 h to ensure that all the test specimens readi this temperature. Then alow the furnace to cool down to room temperature, Take the test specimens out of the baking container. Remove any packing material whlcii may be sticking to the surface of the test specimens. Determine the mass m1of each baked lest specimen to 0,1 g.
7 Expression of results
Calculate the relative mass loss during the baIting process, called the loss on baking, using the following equabon:
8 Precision (determined in accordance with ISO 5725-2)
Repeatability (r) = 0,9% (absolute)
Reproducibilily CR) = 2,3% (absolute)
The number 01 degrees 01 freedom, is. nimiber of laboratories (6) number ci samples (4). was 24.
NOTE The preoernn will be inied by veflabdity In the material.
9 Test report
The test report shall include the following informabon:
a) a reference to ISO 20202:
b) all details necessary for identificabon of the sample tested:
C) the temperature used for preparation of the green test speameris:
d) the results cii the test. i.e. the loss on baking,
e) the date of the test;
1) details of any unusual features noted during the determwistion;
g) details of any operation not Included In ISO 20202 or regarded as optional.