GB/T 38510-2020 English PDF (GBT38510-2020)

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GB/T 38510-2020: Evaluation of self-sealing performance for tyres coated with self-sealing material
GB/T 38510-2020
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 83.160.10
G 41
Evaluation of self-sealing performance for tyres
coated with self-sealing material
ISSUED ON: MARCH 06, 2020
IMPLEMENTED ON: FEBRUARY 01, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3
Introduction ... 4
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Evaluation requirements ... 6
5 Test methods ... 7
Annex A (informative) Identification and warning information ... 9
Annex B (normative) Test nails and puncturing method ... 10
Evaluation of self-sealing performance for tyres
coated with self-sealing material
1 Scope
This Standard specifies the evaluation requirements and test methods for self-
sealing performance of tyres coated with self-sealing material.
This Standard applies to pneumatic tubeless passenger car radial tyres with a
coating inside the crown and with anti-leakage function after puncturing.
2 Normative references
The following referenced documents are indispensable for the application of
this document. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any
amendments) applies.
GB/T 4502 Laboratory test methods for passenger car tyres capabilities
GB/T 6326 Tyre terms and definitions
GB 9743 Passenger car tyres
3 Terms and definitions
For the purpose of this document, the terms and definitions defined in GB/T
6326 and the following apply.
3.1
tyres coated with self-sealing material
Tyres of which the inner side of the crown is coated with self-sealing material.
After the crown is punctured by foreign matters (diameter not greater than 5
mm), whether the foreign matters are pulled out or remain in the crown, the
tyres still have a good sealing performance.
5 Test methods
5.1 Static airtightness
5.1.1 Static airtightness test at indoor normal temperature
INSTALL the test tyre on the measuring rim; FILL it with 250 kPa air pressure.
After placing at the test ambient temperature of 23 °C ± 2 °C for 3 h, the air
pressure of the test tyre is re-calibrated to 250 kPa. PUNCTURE with nails
according to the requirements of Annex B. After placing for 24 h, PULL OUT all
the nails. After 24 h, MEASURE and RECORD the air pressure again.
5.1.2 Static airtightness test at indoor low temperature
INSTALL the test tyre on the measuring rim; FILL it with 250 kPa air pressure.
After placing at room temperature for 3 h, MEASURE and RECORD the air
pressure value of the tyre. SET the temperature of the low temperature
refrigeration device (temperature control range -40 °C ~ 0 °C) to -25 °C. After
the temperature is constant, PUT the tyre in and continue to freeze for not less
than 12 h. REMOVE the tyre, PUNCTURE it with the nails that have been
frozen at the same low temperature for more than 12 h as soon as possible
according to the requirements of Annex B, and PULL OUT all the test nails
within 3 min. Then PUT the tyre into the same low temperature environment as
above and continue to freeze for more than 12 h. REMOVE the tyre and leave
it at room temperature for 24 h. MEASURE and RECORD the air pressure value
of the tyre again.
5.2 Endurance test
5.2.1 Nail-pull-out endurance test
The test tyre is punctured with nails according to the requirements of Annex B,
and then immediately pull out all the nails. After placing for 3 h, carry out the
endurance test according to GB/T 4502.
5.2.2 Nail-not-pull-out endurance test
The test tyre is punctured with nails according to the requirements of Annex B.
After placing for 3 h, carry out the endurance test according to GB/T 4502.
5.3 High-speed performance test
The test tyre is punctured with nails according to the requirements of Annex B,
and then immediately pull out all the nails. After placing for 3 h, carry out the
high-speed performance test according to GB/T 4502.
5.4 Outdoor low-temperature road endurance performance test
5.4.1 Test requirements
This test is only carried out when the coating formulation, production process
changes or when it is re-produced. Test tyres shall be snow tyres or icy tyres.
5.4.2 Test procedure
5.4.2.1 INSTALL four test tyres on the rim used by the test vehicle; FILL them
with 250 kPa air pressure.
5.4.2.2 The inflated test tyre rim assembly is placed at an ambient temperature
of -35 °C ~ -20 °C for more than 3 h.
5.4.2.3 According to the requirements of Annex B, the four tyres are punctured
with nails. The nails of two tyres are pulled out, and the nails of the other two
tyres are not pulled out.
5.4.2.4 INSTALL the two nail-not-pull-out tyres on the front axle of the test
vehicle, and the two nail-pull-out tyres on the rear axle of the test vehicle. The
test load carried by the test tyres on both sides of each axle shall be 60 % to
80 % of the load capacity corresponding to its load index.
5.4.2.5 RECALIBRATE the air pressure of the test tyres to 250 kPa.
5.4.2.6 At an ambient temperature of -35 °C ~ -20 °C, the test vehicle travels
for a total of 800 km at a speed of (80 ± 10) km/h, and the air pressure of the
tyres is measured and recorded for every (100 ± 10) km on the way. After the
800 km driving distance is over, the vehicle is parked at an ambient temperature
of -35 °C ~ -20 °C for more than 3 h, and the air pressure of the tyres is
measured again and recorded.