GB/T 5988-2022 PDF English
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Refractory products - Determination of permanent change in dimensions on heating
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| GB/T 5988-2007 | English | 130 |
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Refractory products -- Determination of permanent change in dimension on heating
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| GB/T 5988-2004 | English | 319 |
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Dense shaped refractory products -- Determination of permanent change in dimension on heating
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| GB/T 5988-1986 | English | 279 |
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Dense shaped refractory products--Test method of linear changes on reheating
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GB/T 5988-2022: PDF in English (GBT 5988-2022) GB/T 5988-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 81.080
CCS Q 40
Replacing GB/T 5988-2007
Refractory Products – Determination of Permanent Change
in Dimensions on Heating
(ISO 2478.1987, Dense Shaped Refractory Products – Determination of
Permanent Change in Dimensions on Heating; ISO 2477.2005, Shaped
Insulating Refractory Products – Determination of Permanent Change in
Dimensions on Heating, MOD)
ISSUED ON. MARCH 9, 2022
IMPLEMENTED ON. OCTOBER 1, 2022
Issued by. State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword... 3
1 Scope... 5
2 Normative References... 5
3 Terms and Definitions... 5
4 Principle... 6
5 Equipment... 6
6 Specimens... 8
7 Test Steps... 8
8 Calculation of Results... 12
9 Allowable Error... 13
10 Test Report... 14
Appendix A (Informative) Comparison of Structure No. between this Document and
ISO 2478.1987 & ISO 2477.2005... 15
Appendix B (Informative) Technical Differences and Their Causes between this
Document and ISO 2478.1987 & ISO 2477.2005... 17
Refractory Products – Determination of
Permanent Change in Dimensions on Heating
1 Scope
This Document specifies the principle, equipment, specimens, test steps, result calculation and
test report of the test method for permanent change in dimensions on heating of dense shaped
refractory products and shaped insulating refractory products.
This Document is applicable to the determination of permanent in dimensions on heating of
dense shaped refractory products and shaped insulating refractory products.
2 Normative References
The provisions in following documents become the essential provisions of this Document
through reference in this Document. For the dated documents, only the versions with the dates
indicated are applicable to this Document; for the undated documents, only the latest version
(including all the amendments) is applicable to this Document.
GB/T 2997 Test method for bulk density, apparent porosity and true porosity of dense
shaped refractory products (GB/T 2997-2015, ISO 5017.2013, MOD)
GB/T 7321 Sample preparation for testing of shaped refractory products
GB/T 8170 Rules of rounding off for numerical values & expression and judgement of
limiting values
GB/T 10325 Shaped refractory products-rule of acceptance, sampling and inspection
(GB/T 10325-2012, ISO 5022.1979, NEQ)
GB/T 16839.1 Thermocouples - Part 1.EMF specifications and tolerances (GB/T 16839.1-
2018, IEC 60584-1.2013, IDT)
GB/T 18930 Terminology for refractories (GB/T 18930-2020, ISO 836.2001, MOD)
3 Terms and Definitions
For the purposes of this Document, the terms and definitions given in GB/T 18930 apply.
4 Principle
Place the rectangular or cylindrical specimen with measured length or volume in the test furnace;
heat it to the test temperature at the specified heating rate; and keep it for a certain time. After
cooling to room temperature, measure its length or volume again; and calculate its heating
permanent change rate in dimensions on heating or change rate in volume.
5 Equipment
5.1 Heating device
5.1.1 Test furnace
An electric furnace or other type of furnace that meets the requirements of 7.4.1 ~ 7.4.3, with a
temperature difference of no more than ±10 °C in the sample loading area in the furnace. The
specified specimen (see 6.2) can be heated at a specified rate (see 7.4.2) and kept at the test
temperature for a certain period of time.
5.1.2 Thermocouple
At least 3 thermocouples; the thermocouples shall comply with the provisions of GB/T 16839.1.
5.1.3 Temperature recording and display device
When used in conjunction with thermocouples, it can continuously control, record and display
the temperature in the furnace.
5.2 Length measuring device
5.2.1 Length measuring instrument (applicable to dense shaped products)
The measuring instrument consists of a frame, a sample carrier and a dial indicator (as shown
in Figure 1). The frame has a base with a polished upper surface and a vertical smooth circular
column. The dial indicator is installed on the column and can slide up and down along the
column and make circular motion around the column with an accuracy of 0.01mm. The sample
carrier is placed on the base; and the bottom surface is a polished plane, which can move freely
on the surface of the base. The upper and lower surfaces of the sample carrier are square; and
three sample supports of equal height arranged in an equilateral triangle and two positioning
pins higher than the sample supports are fixed on the top; and a diagonal positioning mark is
engraved on one corner. The installation position of the sample carrier sample support and
positioning pin is shown in Figure 2.
5.3 Volume measuring device
The equipment, specified in GB/T 2997, is used to measure the total volume of dense shaped
refractory product samples.
5.4 Electric heating blast drying oven
The temperature control can meet 110℃±5℃.
6 Specimens
6.1 Sampling
Performed in accordance with GB/T 10325, or the sampling plan can be determined by
negotiation between the relevant parties.
6.2 Preparation of specimens
6.2.1 Dense shaped refractory products
The preparation of the specimen is carried out in accordance with GB/T 7321.Generally, one
specimen is prepared from each sample; and the number of specimens cut from each sample
shall be the same.
The size of the rectangular specimen is 50mm×50mm×(60±2)mm; and the size of the
cylindrical sample is 50mm in diameter and (60±2)mm in height. The 60mm dimension of the
specimen shall be consistent with the molding and pressurizing direction of the brick. The
50mm×50mm face of the cuboid or the end face of the cylinder shall be ground flat and parallel
to each other before testing. When the sample of the above dimensions cannot be obtained from
the brick, a suitable sample can be made according to the provisions of GB/T 2997.
6.2.2 Shaped insulating refractory products
One specimen is made from each sample; and more than one can be made if the sample size
allows. Specimen size. 100mm×114mm×65mm or 100mm×114mm×75mm.
If the above specimen cannot be made due to sample size restrictions, a specimen with a length
of 100mm shall be cut from the sample and its thickness and width shall be recorded.
The two faces of the sample 100mm apart shall be flat and parallel to each other.
7 Test Steps
7.1 Specimen drying
Dry the specimen in an electric drying oven at 110℃±5℃. Specimens that need to use the
volume measurement method in 7.2.2 shall be dried to constant weight according to the
provisions of GB/T 2997.
7.2 Specimen measurement
7.2.1 Length measuring instrument method (dense shaped refractory products)
Calibrate the length measuring device with a calibration block. Place the sample vertically on
the sample carrier with a height of 60mm. For rectangular specimens, align a marked corner
with the diagonal mark of the sample carrier. For cylindrical specimens, align any two mutually
perpendicular diameters with the diagonal on the sample carrier; and mark them so that the
sample can be measured at the same position after heating.
Move the sample carrier with the specimen on the base and measure the length at 4 positions
on the top surface of the specimen, accurate to 0.01mm. For rectangular specimens, the 4
positions are on the diagonal line of the top surface of the specimen, 20mm~25mm away from
each corner. For cylindrical specimens, the 4 positions are on two perpendicular diameters of
the top surface of the specimen, 10mm~15mm away from the circumference. Mark the
measurement position and record the length of each measurement point (L0).
7.2.2 Volume measuring method (dense shaped refractory products)
Measure the volume density of the specimen according to GB/T 2997; and calculate the volume
(Vb) of the specimen according to Formula (1).
Where.
Vb – total volume of specimen, in cm3;
m1 - the mass of the saturated specimen suspended in the immersion liquid, in g;
m2 - Mass of saturated specimen in air, in g;
ρ – density of immersion liquid, in g/cm3.
7.2.3 Length measuring method (shaped insulation refractory products)
For shaped insulation products, use the length measuring instrument (5.2.2) to measure the
distance (L0) between the two opposite surfaces of the specimen in the 100mm length direction.
Perform 4 measurements in total, accurate to 0.1mm. Thereof, two measurements (EF and GH)
are along the center line of the top and bottom surfaces; and the other two measurements (AB
and CD) are along the center line of the front and back surfaces of the specimen. The measuring
During the thermal preservation period, the temperature recorded by any of the three
thermocouples is within ±10℃ of the test temperature. The average temperature of the three
thermocouples is recorded as the actual test temperature. The thermal preservation time is
determined in accordance with the technical conditions of the product or by negotiation
between the parties concerned.
7.4.4 Cooling
After stopping heating, the furnace is cooled naturally to room temperature; and the specimen
is cooled with the furnace.
7.5 Measurement of burnt specimens
7.5.1 Length measuring instrument method (dense shaped refractory products)
Measure the length (L1) of the original measuring position of the specimen according to the
provisions of 7.2.1.Check the specimen. If defects such as nodules and bubbles generated
during the heating process are found on the original measuring position, it shall be replaced by
a nearby unaffected measuring point.
7.5.2 Volume measuring method (compact shaped refractory products)
Measure the total volume of the sample in the same way as in 7.2.2.
7.5.3 Length measuring method (shaped thermal insulating refractory products)
Check and record the appearance of the specimen; and measure the length (L1) of the specimen
at the original measuring position in accordance with the provisions of 7.2.3.
8 Calculation of Results
8.1 The heating permanent linear change (Lc) is calculated by the length change rate of the
specimen before and after heating. The length measuring instrument method and the length
measuring method are calculated according to Formula (2); and the average value of the linear
change at the 4 measuring positions is taken as the heating permanent change in dimensions on
heating of the specimen. The volume measuring method is calculated according to Formula (3).
Where.
Lc – permanent change in dimensions on heating, in %;
L1 - length value measured at each point after the specimen is heated, in mm;
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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