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QC/T 241-2011 PDF in English


QC/T 241-2011 (QC/T241-2011, QCT 241-2011, QCT241-2011)
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QC/T 241-2011: PDF in English (QCT 241-2011)

QC/T 241-2011
QC
AUTOMOBILE INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 43.040.50
T 23
Replacing QC/T 241-1997
Air leakage test methods of automobile wheels for
tubeless tires
ISSUED ON: MAY 18, 2011
IMPLEMENTED ON: AUGUST 01, 2011
Issued by: Ministry of Industry and Information Technology of PRC
Table of Contents
Announcement ... 3 
Foreword ... 6 
1 Scope ... 7 
2 Normative references ... 7 
3 Terms and definitions ... 7 
4 Samples ... 7 
5 Test equipment ... 7 
6 Test method ... 9 
7 Evaluation of test results ... 11 
Appendix A (Informative) Several basic concepts in helium test method ... 12 
Appendix B (Informative) Helium test conditions ... 15 
Air leakage test methods of automobile wheels for
tubeless tires
1 Scope
This standard specifies two test methods, for the air tightness of automobile
wheels, namely the compressed air test method and the helium test method.
This standard applies to automobile wheels fitted with tubeless tires.
2 Normative references
The following documents are essential to the application of 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 standard.
GB/T 2933 Wheels and rims for pneumatic tyres - Vocabulary, designation
and marking
3 Terms and definitions
The terms and definitions, which are established by GB/T 2933, are applicable
to this standard.
4 Samples
The sample used for the test shall be a new wheel or rim, that has not been
tested or used, AND the surface has not been painted, BUT other processes
have been completed. The surface of the sample shall be clean AND free of
grease. When using the helium test method, the surface of the sample shall be
dry AND there shall be no visible moisture.
5 Test equipment
5.1 Figure 1a) shows the schematic diagram of the wheel test device of the
compressed air test method.
5.2 Figure 1b) shows the schematic diagram of the rim test device of the
6.1.2.3 Fill the wheel or rim, with compressed air, to the specified pressure.
6.1.2.4 For those using the test device as shown in Figure 1a), immerse all the
wheels in water, to check whether there is any air leakage on the rim. For those
using the test device as shown in Figure 1b), evenly apply inspection fluid to
the weld, to check whether the weld is leaking.
6.1.2.5 Release the compressed air, inside the wheel or rim, to normal pressure;
open the sealing plate; take out the wheel or rim.
6.2 Helium test method
6.2.1 Test conditions:
The main test conditions include: the purity of the industrial helium used, the
concentration of helium in the test gas, the pressure of the test gas outside the
wheel, the vacuum inside the wheel. It is recommended to use Appendix B.
6.2.2 Test procedure:
6.2.2.1 Block the wheel's valve hole.
6.2.2.2 Place the wheel on the lower sealing plate.
6.2.2.3 Move the sealing cover downwards, to make it tightly press on the lower
sealing plate. At the same time, move the upper sealing plate downwards, to
make it tightly press on the upper rim.
6.2.2.4 Vacuum the inside of the wheel. If the preset vacuum is not reached,
within the specified time, it means that the tightness is not good, OR the wheel
leakage is particularly serious; THEN the test process is aborted and an alarm
is issued. If it can be reached, continue to vacuum to the vacuum, which is
required by the test.
6.2.2.5 Vacuum the outside of the wheel.
6.2.2.6 Fill the outside of the wheel with test gas, to the required pressure. The
pressure's holding time is 3s.
6.2.2.7 Measure the partial pressure of helium, which leaks into the wheel.
Convert it into a helium leak rate. Display the measurement result. Compare
with the set critical leak rate, to determine whether the tested wheel is qualified.
6.2.2.8 The inside of the wheel is connected to the atmosphere, to restore it to
a normal pressure state.
6.2.2.9 After the testing gas, which is outside the wheel, is pumped into the
recovery station, it is connected to the atmosphere, to restore it to a normal
pressure state.
6.2.2.10 Open the sealing cover and the upper sealing plate.
6.2.2.11 Remove the wheel.
Note: For the wheel, that is judged to be unqualified, OR the wheel, that is vacuuming
is suspended and alarmed, it can be re-examined once.
7 Evaluation of test results
7.1 Compressed air test method
Within 30s after the inflation reaches the specified air pressure, if any part of
the wheel or rim is found to have air bubbles escape, it is determined that the
wheel or rim is unqualified.
7.2 Helium test method
Compare the measured leak rate with the preset critical leak rate. When it is
less than the critical leakage rate, it is judged as qualified; otherwise, it is judged
as unqualified.
See Appendix A for the method of determining the critical leakage rate.
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.