This standard specifies the definition, principle, equipment, specimen, test procedure, result calculation and test report of the reburning line change of shaped insulating refractory products. This standard is applicable to the determination of the reburning line change of shaped insulating refractory products. GB/T 3997.1-1998 Test method for reburning line change of shaped insulating refractory products GB/T3997.1-1998 Standard download decompression password: www.bzxz.net

GB/T3997.1—1998
This standard is equivalent to ISO2477:1987 "Shaped insulating refractory products-Determination of reburning line changes", and is supplemented in the following aspects: - Sampling quantity:
- Sample size;
Holding time;
Result expression.
This standard differs from the original national standard GB/T3997.1—1983 in the following aspects: - Sample size,
Placement of the sample in the furnace; bZxz.net
Heating system.
From the date of implementation of this standard, it replaces GB/T3997.1--1983. This standard is proposed by the State Metallurgical Industry Bureau. This standard is under the jurisdiction of the National Technical Committee for Standardization of Refractory Materials. Drafting units of this standard: Luoyang Refractory Materials Research Institute of the Ministry of Metallurgical Industry and Lianyungang Energy-saving Building Materials Factory of Jiangsu Province. The main drafters of this standard are Wei Lingxuan, Zhou Jing, Zhang Qing and Zhong Zhaoyu. 114
GB/T3997.1-1998
ISOForeword
ISO (International Organization for Standardization) is a worldwide federation of international standard bodies (ISO member bodies). The work of formulating international standards is usually carried out by ISO's technical committees. If each member body is interested in a project established by a technical committee, it has the right to participate in the work of the committee. International organizations (official or unofficial) that have a relationship with ISO may also participate in the relevant work. The draft international standard adopted by the technical committee shall be submitted to the member bodies for voting. It can only be published as an international standard if it obtains at least 75% of the votes of the member bodies participating in the voting. International Standard ISO2477 was formulated by ISO/TC33 International Organization for Standardization Technical Committee on Refractories. This standard version (second version) replaces the first version (ISO2477:1973), and the main differences are the selection, size, placement and heating system of the specimen.
Users should note that international standards are frequently revised. Unless otherwise specified, the referenced standards shall be the latest versions. 115
1 Scope
National Standard of the People's Republic of China
Test method for linear change of shaped insulating refractory products on reburning
Shaped insulating refractory products--Determination of permanent change in dimension on heatingGB/T 3997. 1 -1998
eqv IsO 2477:1987
Replaces GB/T3997.1—1983
This standard specifies the definition, principle, equipment, specimens, test procedures, result calculation and test report of linear change of shaped insulating refractory products on reburning.
This standard is applicable to the determination of linear change of shaped insulating refractory products on reburning. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. All versions are valid when this standard is published. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T2998--1982 Test method for bulk density and true porosity of shaped insulating refractory products GB/T8170-1987 Rules for rounding off values
3 Definitions
This standard adopts the following definitions.
3.1 Reburning line change refers to the residual expansion or contraction produced after the sample is heated to a specified temperature, kept warm for a certain period of time, and cooled to room temperature.
3.2 Insulating refractory products According to GB/T2998, the refractory products with a true porosity greater than 45% shall be determined. 4 Principle
Place a rectangular prism sample of measured length in a furnace with an oxidizing atmosphere, heat it to the test temperature at a specified rate, keep it warm for a certain period of time, cool it to room temperature, then measure its length and calculate the change in the reburning line. 5 Equipment
5.1 Test furnace
An electric furnace or other furnace must be used, and the furnace must have a continuous oxidizing atmosphere. The test furnace should be able to carry out tests under the conditions specified in Article 7.6. 5.2 Thermocouples
At least 3, to measure the temperature distribution of the space occupied by the sample. 5.3 Temperature/time recording device
Use with the thermocouples in Article 5.2 to obtain continuous temperature records. 5.4 Length measuring device
Guohao Quality and Technical Supervision Bureau approved on December 15, 1998 116
Implementation on August 1, 1999
GB/T 3997. 1 - 1998
Use a vernier caliper or other measuring instrument, accurate to 0.1mm. 5.5 The oven
should be able to blow air and ensure smooth airflow.
6 Test specimens
6.1 Number of test specimens: The number of samples to be taken should be based on the sampling plan agreed upon by the relevant parties. Note: Generally, at least one test specimen shall be taken from each of the three products for each test. If the size allows, more than one test specimen may be taken from each sample. 6.2 Sample size: 100mm×114mm×64mm or 100mm×114mm×76mm, 100mm should be cut in the length direction of the product; 114mm and 64mm or 76mm should be cut in the width and thickness direction of the product respectively. The sample size can also be 100mmX114mmX65mm or 100mmX114mm×100mm. 6.3 When the above sample cannot be taken, a sample with a length of 100mm should be cut from the sample and its thickness and width should be recorded. 6.4 Before the test, the two opposite surfaces of the sample with a distance of 100mm must be flat and parallel to each other. 7 Test steps
7.1 Before the test, the sample must be dried at 110℃±5℃ to constant weight. 7.2 Measurement of the sample
The measurement of the linear change size should be carried out at 4 positions in the length direction of 100mm of the sample, see Figure 1. The point 15mm from the edge of the center line of the two end faces should be used as the measurement position, and the measurement should be accurate to 0.2mm. The measurement position should be marked with refractory paint.
7.3 Sample placement
Use one side of the sample 100mm×64mm (or 100mm×76mm) as the bottom surface and place it in the uniform temperature zone of the test furnace. Avoid direct radiation from the heating element of the electric furnace or the flame of the gas furnace. The samples shall not be stacked. In order to allow the hot gas to flow freely, the distance between the samples shall not be less than 50mm, and the distance from the furnace wall shall not be less than 70mm.
7.4 Test temperature
The test temperature should be 800℃ or increase the temperature by multiples of 50℃7.5 Temperature measurement and distribution
At least 3 thermocouples (away from the furnace wall and heating elements and not in contact with the flame) are used to measure and record the temperature distribution of the space occupied by the sample. The temperature difference of the 3 thermocouples shall not exceed 20℃.
7.6 Heating system
7.6.1 The heating rate must comply with the following provisions: Test temperature below 1250℃
Room temperature to 50℃ below the test temperature:
Last 50℃
Test temperature above 1250℃
Room temperature to 1200℃:
1200℃ to 50℃ below the test temperature:
Last 50℃
Note: For the last 50℃, the heating rate should be 1-2℃/min. 5～10℃/min
1～10C/min
5～10℃/min
2～5℃/min
1～5℃/min
7.6.2 Insulation
15 from the edge
GB/T 3997. 11998
L (100 nominal)
Figure 1 Measurement and placement of sample dimensions
The difference between the measured temperature value of each thermocouple in the three thermocouples and the test temperature is within 10℃, and the insulation is carried out for 12h, or the insulation time is determined according to the technical conditions. The average value of the temperature of the three thermocouples is recorded as the actual test temperature. 7.6.3 If it is heated by gas, take a gas sample around the sample within the heating time specified in Article 7.6 and determine its oxygen content. 7.6.4 Cooling
After stopping heating, the sample is cooled naturally to room temperature with the furnace. 7.7 Post-firing sample measurement
Record the appearance of the sample. As specified in 7.2, measure the distance between the two opposite surfaces of each sample. 8 Result calculation
Calculate the re-firing line change rate according to the following formula: AL
Re-firing line change rate of the sample, %;
L,— Length of sample after heating, mm,
La——Length of sample before heating, mm.
List the 4 linear change rates of each sample and their average values ​​as the test results. Increase in size is positive (+10), decrease in size is negative (-). Note: Generally, the linear change results of reburning are calculated to the first decimal place, and the values ​​after the decimal place are processed according to GB/T8170. 118
9Test report
The test report should include the following contents:
a) Commissioning unit;
b) Name and number of test sample:
c) Type of test furnace used;
d) Dimensions of test sample and its position in the furnace;
e) Number of test samples taken for each sample;
f) Implementation standard;
g) Test temperature and holding time;
GB/T 3997. 1—1998
h) Single value of each test sample and each brick and its average value;
i) Oxygen content in the furnace (for gas heating furnace);
k) Test personnel;
1) Test date.
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