QC/T 241-2024 English PDF (QCT241-2024)

Delivery: 3 seconds. Download true-PDF + Invoice.
Get QUOTATION in 1-minute: Click QC/T 241-2024
Historical versions: QC/T 241-2024
Preview True-PDF (Reload/Scroll if blank)

QC/T 241-2024: Air leakage detection methods of automobile wheels for tubeless tires
QC/T 241-2024
QC
AUTOMOTIVE INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 43.040.50
CCS T 22
Replacing QC/T 241-2011
Air Leakage Detection Methods of Automobile Wheels for
Tubeless Tires
ISSUED ON: JULY 19, 2024
IMPLEMENTED ON: JANUARY 1, 2025
Issued by: Ministry of Industry and Information Technology of the People’s
Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 4
4 Samples ... 4
5 Detection Methods ... 5
5.1 Helium Detection Method ... 5
5.2 Comparison Detection Method ... 6
5.3 Hydrogen Detection Method ... 8
5.4 Differential Pressure Detection Method ... 9
5.5 Water Detection Method ... 10
5.6 Compressed Air Method ... 11
Appendix A (informative) Method of Determining Leak Rate ... 13
Foreword
This document was drafted in accordance with the rules provided in GB/T 1.1-2020 Directives
for Standardization - Part 1: Rules for the Structure and Drafting of Standardizing Documents.
This document serves as a replacement for QC/T 241-2011 Air Leakage Test Methods of
Automobile Wheels for Tubeless Tires. In comparison with QC/T 241-2011, apart from
structural adjustments and editorial modifications, the main technical changes are as follows:
a) The scope of application is modified (see Chapter 1; Chapter 1 of Version 2011);
b) The terms and definitions are modified (see Chapter 3; Chapter 3 of Version 2011);
c) The definition of sample is modified (see Chapter 4; Chapter 4 of Version 2011);
d) The water detection method and compressed air method are modified (see Chapter 5;
Chapter 6 of Version 2011);
e) The comparison detection method, hydrogen detection method and differential
pressure detection method are added (see Chapter 5).
Please be noted that certain content of this document may involve patents. The institution
issuing this document does not undertake the responsibility of identifying these patents.
This document was proposed by and shall be under the jurisdiction of National Technical
Committee 114 on Auto of Standardization Administration of China (SAC/TC 114).
The drafting organizations of this document: Dongfeng Motor Wheel Suizhou Co., Ltd.; CITIC
Dicastal Co., Ltd.; Zhejiang Jingu Co., Ltd.; Xingmin Lichi Co., Ltd.; Dongfeng Motor Chassis
Systems Co., Ltd.; Wanfeng Auto Wheels Co., Ltd.; FAWAY Automobile Components Co., Ltd.
Wheel Branch Company; Zhejiang Jinfei Kaida Wheel Co., Ltd.; Jiangsu Pomlead Co., Ltd.
The main drafters of this document: Wang Xianfu, You Guoxiang, Li Shide, Ye Yanfei, Chen
Yunjing, Cheng Xiaoqiang, Liu Chunhai, Mao Qiuxian, Zhang Shijiang, Zhu Hongbin, Dong
Qi.
The issuing of the previous versions:
---Firstly issued in 1997 as QC/T 241-1997 and firstly revised in 2011;
---This is the second revision.
Air Leakage Detection Methods of Automobile Wheels for
Tubeless Tires
1 Scope
This document describes six detection methods for the air leakage of automobile wheels,
namely, helium detection method, comparison detection method, hydrogen detection method,
differential pressure detection method, water detection method and compressed air method.
This document is applicable to automobile wheels equipped with tubeless tires. Among them,
helium detection method and water detection method are recommended for light alloy wheels;
comparison detection method, hydrogen detection method, differential pressure detection
method and compressed air method are recommended for steel wheels.
2 Normative References
The content of the following documents constitutes indispensable clauses of this document
through normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB/T 2933 Wheels and Rims for Pneumatic Tyres - Vocabulary, Designation and Marking
3 Terms and Definitions
The terms and definitions defined in GB/T 2933, and the following are applicable to this
document.
3.1 leak rate
The amount of leakage caused by pressure difference per unit time.
NOTE: the unit is Pa  m3/s.
3.2 critical leakage rate
The leak rate threshold used to qualify a component.
4 Samples
The samples for detection shall be new wheels or rims with unpainted and unused surfaces.
the specified time, it means that the sealing is not good, or the wheel leakage is particularly
serious, then, suspend the detection process and issue an alarm; if the preset vacuum degree can
be reached, continue to vacuumize, until reaching the vacuum degree of not greater than 20 Pa
as requested by detection.
5.1.3.5 Vacuumize the outside of the wheel.
5.1.3.6 Fill the outside of the wheel with detection gas to a pressure above 0.3 MPa and maintain
the pressure for 3 seconds.
5.1.3.7 Measure the helium partial pressure leaking into the wheel, convert it into helium leak
rate and display the measurement result.
5.1.3.8 The inside of the wheel is connected to the atmosphere, allowing it to return to normal
pressure.
5.1.3.9 After the detection gas outside the wheel is pumped into the recycling station, it is
connected to the atmosphere, allowing it to return to normal pressure.
5.1.3.10 Open the sealing cover and upper sealing plate.
5.1.3.11 Remove the wheel.
5.1.4 Evaluation of detection result
Compare the measured leak rate with a preset critical leakage rate. When it is smaller than the
critical leakage rate, it shall be determined to be qualified; otherwise, it shall be determined to
be disqualified. See Appendix A for the method of determining the critical leakage rate.
5.2 Comparison Detection Method
5.2.1 Detection equipment
The detection equipment shall have a sealing device, two detection heads and an air inlet pipe
(see Figure 2).
Appendix A
(informative)
Method of Determining Leak Rate
A.1 Definition of Wheel Leakage
Under room-temperature conditions, for wheel and tire assemblies, in a certain tire volume, fill
the air pressure to the corresponding value, and within 6 months (180 days), the air pressure
drop rate is greater than 10%.
A.2 Calculation of Leak Rate
Formula (A.1) represents the changes in volume and pressure per unit time.
When the volume is constant, the calculation formula is (A.2):
Where,
q---the leak rate, expressed in [Pa  (m3/s)];
p---the pressure change, expressed in (Pa);
V---the volume, expressed in (m3);
t---the time, expressed in (s);
In accordance with the definition of wheel leakage, for passenger vehicle wheel and tire
assemblies, under room-temperature conditions, in a 25 L tire volume, fill the air pressure to
0.2 MPa, and within 6 months (180 days), the air pressure drops by 0.02 MPa. The
corresponding air leak rate is:
A.3 Conversion of Leak Rate
For the same leaking body, under different detection conditions, such as: internal air pressure,
external air pressure and detection gas, etc., the leak rate is converted using Formula (A.3).