GB/T 38494-2020 English PDF (GBT38494-2020)

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GB/T 38494-2020: Test method for impact resistance of ceramic wares
GB/T 38494-2020
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 81.060.20
Y 24
Test Method for Impact Resistance of Ceramic Wares
ISSUED ON: MARCH 06, 2020
IMPLEMENTED ON: OCTOBER 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Terms and Definitions ... 4
3 Principle ... 4
4 Apparatus and Utensils ... 5
5 Specimen ... 5
6 Procedures ... 5
7 Calculation Formula ... 6
8 Presentation of Results ... 7
9 Test Report ... 7
Test Method for Impact Resistance of Ceramic Wares
1 Scope
This Standard specifies the test method for the impact resistance of ceramic wares.
This Standard is applicable to the impact test of the centre and edge of the bottom of
the ceramic wares.
2 Terms and Definitions
For the purpose of this document, the following terms and definitions apply.
2.1 Impact energy
The energy that is required for generating cracks or breakage of ceramic wares.
2.2 Impact resistance
The impact energy (edge impact strength) or the square ratio of impact energy to
thickness (centric impact strength) that is required for generating cracks or breakage
of ceramic wares.
2.3 Centric position
The centre of the bottom of the ceramic wares.
2.4 Edge position
The position, when the bottom of the ceramic ware is placed flat on a plane, that the
edge of the mouth is in contact with the pendulum.
3 Principle
The method, when the pendulum is released from a certain height to the lowest point,
and the potential energy is converted into kinetic energy to impact the ceramic wares
to cause cracks or breakage, which is used to characterize the impact resistance of
the ceramic wares.
6.1.3 Incremental test
Place the pendulum at the lowest energy position; release the pendulum to impact the
specimen; block the pendulum with hand or other objects to avoid secondary impact;
observe whether the specimen is cracked or damaged. Gradually increase the impact
energy until the sample is cracked or damaged.
6.1.4 Results recording
Record the impact energy when cracks or breakage occur, and measure the thickness
of the centric point of the specimen.
6.2 Edge impact test
6.2.1 Placement of the sample
The sample is placed flat on the fixed table and fixed; the pendulum is placed at the
lowest point. And the sample fixed table is adjusted so that the impact point of the
pendulum is at the thinnest and most prominent position of the edge of the specimen.
6.2.2 Fixed value test
Place the pendulum at a predetermined energy position; release the pendulum to
impact the specimen; block the pendulum with hand or other objects to avoid
secondary impact. Take out the specimen, and observe whether the specimen is
cracked or damaged.
6.2.3 Incremental test
Place the pendulum at the lowest energy position; release the pendulum to impact the
specimen; block the pendulum with hand or other objects to avoid secondary impact;
observe whether the sample is cracked or damaged. Gradually increase the impact
energy until the sample is cracked or damaged.
6.2.4 Results recording
Record the impact energy when cracks or breakage occur.
7 Calculation Formula
The calculation of impact resistance in the centric impact test is shown in Formula (1):
Where: