This standard is applicable to the determination of room temperature impact toughness of daily-use ceramics. GB/T 4742-1984 Determination of impact toughness of daily-use ceramics GB/T4742-1984 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test method for lashing toughness of domestic ceramic
Standard test method for lashing toughness of domestic ceramic
This standard applies to the test of room temperature impact toughness of domestic ceramic. 1 Definition
Impact toughness is the work absorbed per unit area at the fracture when the specimen is subjected to simple beam impact. 2 Equipment and tools
UDC 666.64: 620
.178.7
GB No. 712-B4
2.1XCJ-40 impact testing machine: The measuring range is 5kgf.cm, and the support span is 40mm for small specimens and 70mm for large specimens. 2.2 Vernier caliper, with an accuracy of 0.02mm.
3.1 See Figure 1 for specimen dimensions.
Figure 1 Sample specificationsWww.bzxZ.net
Small sample: L=60mm B=4mm H=6mm
6=2mmh=4mmh2=2mm
Large sample: L=100mmB=10mmH=15mm
h=10mh2=5mm
3.2 Sample preparation
3.2.1 Cut 10 pieces of roughness slightly larger than the standard sample size from three products, and then use No. 100 diamond sand to process them into standard samples. Clean the surface of the sample, dry it at a temperature of 105-110℃, and cool it in a dryer for testing. 3.2.2 For products that are difficult to cut the above samples directly, the samples can be made using the same process as the product production. 3.2.3 The sample must be carefully inspected before testing, and no obvious defects caused by turning the sample are allowed. 4 Measurement steps
Table, 1 Install the pendulum and calibrate the instrument (refer to the instruction manual). 4.2 Install the sample, as shown in Figure 2.
National Bureau of Standards Issued on November 2, 1984
Implemented on August 1, 1985
GB 4742-84
Figure 2 Sample loading diagram
Sample positioning plate
4.3 Raise the pendulum to the pre-elevation angle position, place the passive pointer at 10° on the right, release the pendulum and let it fall freely. When the sample is broken, the energy value indicated by the pointer is the impact energy absorbed by the sample. 4.4 Measure the thickness and width of the sample at the fracture (accurate to 0.1mm). 5 Measurement results
5.1 Impact toughness is calculated according to formula (1):
-impact toughness, Nm/m2
Formula t: ak-
W Impact energy absorbed by the sample, N·ms
-Cross-sectional area of ​​the sample at the fracture, m2.
5.2 Data processing
5.2.1 When the maximum relative deviation of all the measured strength values ​​of the specimens is less than or equal to 15%, their average value shall be taken as the test result.
Maximum relative deviation (%) =
[maximum value (or minimum value) - average value] Average value
5.2.2 When the maximum relative deviation is greater than 15%, the value with the largest relative deviation shall be discarded first, and then the remaining measured values ​​shall be calculated and verified according to the above method until they meet the requirements.
5.2.3 If the number of discarded measured values ​​reaches 40% of the total number of specimens, the sample shall be re-prepared for testing. 6 Test records and reports
6.1 The test records include the name of the specimen, the specimen number, the source of the specimen, the type of pendulum, the support span, the absorbed energy of the specimen, the section thickness, the section width, the section cross-sectional area, the data discarded, the final result, the test date and the inspector. 6.2 The test report must also indicate the specimen size and support span when reporting the results. 79
Additional Notes:
4742-84
This standard was proposed by the Ministry of Light Industry of the People's Republic of China and is under the technical jurisdiction of the Ceramics Research Institute of the Ministry of Light Industry. This standard was drafted by the Hunan Ceramics Research Institute. The main drafters of this standard are Peng Binjie and Wang Hegao. 80
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