QC/T 669-2019 English PDF (QCT669-2019)

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QC/T 669-2019: Automotive Air-Condition Pipe-Fittings and Pipes
QC/T 669-2019
QC
AUTOMOTIVE INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 43.040.60
T 26
Replacing QC/T 669-2000
Automotive Air-Condition Pipe-Fittings and Pipes
ISSUED ON: DECEMBER 24, 2019
IMPLEMENTED ON: JULY 01, 2020
Issued by: Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword ... 5
1 Scope ... 7
2 Normative References ... 7
3 Terms and Definitions ... 7
4 Model and Code ... 9
5 General Requirements ... 11
6 Requirements for Structure and Size ... 12
Foreword
This Standard was drafted as per the rules specified in GB/T 1.1-2009 Directives for
Standardization – Part 1: Structure and Drafting of Standards.
This Standard replaced QC/T 669-2000 Automotive Air Conditioning (HFC-134a) Pipe
Fittings and Pipes.
Compared with QC/T 669-2000, this Standard has the major differences as follows:
--- After modification, the standard name becomes Automotive Air-Condition Pipe-
Fittings and Pipes;
--- Modify the foreword; cancel the contents of “inequivalently adopt … IMACA305-
1997”, etc. (see Foreword of this Edition);
--- Add the contents of applicable to “HFC-134a/HFO-1234yf”, etc. (see Clause 1 of
this Edition);
--- Modify the partial normative references (see Clause 2 of this Edition);
--- Add the terms and definitions (see Clause 3 of this Edition);
--- Add a comment on the meaning of the abbreviation code in the model and code
(see Clause 4 of this Edition);
--- Modify and cancel the structural types like the flared type, O-ring push-in type,
and barbed push-in hose connector (see Clause 4 of this Edition);
--- Add the structural types like flange connectors, expansion valve inlet and outlet
flange connector, and external muffler of pipe (see Clause 4 of this Edition);
--- Add the sealing types like single-slot radial, double-slot radial and combined
sealing (see Clause 4 of this Edition);
--- Modify the description of the corrosion resistance requirements of pipe fittings
and pipes (see 5.2 of this Edition);
--- Add the metric connection thread specifications (see 5.3 of this Edition);
--- Add the requirements for thread connection tightening torque (see 5.4 of this
edition);
--- Modify the description of the appearance requirements of pipe fittings and pipes
(see 5.5 of this Edition);
--- Add the requirements for the sealing surface roughness of the pipe-fittings (see
Automotive Air-Condition Pipe-Fittings and Pipes
1 Scope
This Standard specifies the structural type, size and technical requirements of pipe-
fittings and pipe ends for automobile air-conditioning system.
This Standard is applicable to pipe-fittings and pipes for HFC-134a/HFO-1234yf
systems of automobile air conditioner.
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 document.
GB/T 192 General Purpose Metric Screw Threads – Basic Profile
GB/T 196 General Purpose Metric Screw Threads – Basic Dimensions
GB/T 197 General Purpose Metric Screw Threads – Tolerances
GB/T 3934 Specification of Gauges for General Purpose Screw Threads
GB/T 10125 Corrosion Tests in Artificial Atmospheres - Salt Spray Tests
GB/T 30512 Requirements for Prohibited Substances on Automobiles
3 Terms and Definitions
For the purpose of this Standard, the following terms and definitions apply.
3.1 Connecting thread tightening torque
The recommended tightening torque of the connecting thread in the assembly is
divided into the connector connecting thread tightening torque and the flange
connecting thread tightening torque.
3.2 Type of O-ring
The recommended specifications of O-rings for sealing connectors are expressed by
their inner diameter and cross-sectional diameter.
3.3 Radial anti-rotating torque
After the sealing connectors are welded or riveted with pipes, the minimum torque that
makes the relevant rotation between connectors and pipes around the axis.
3.4 Axial tensile force
After the sealing connectors are welded or riveted with pipes, the minimum tensile
force between the connectors and the pipes in the two directions along the axis. The
tensile rate is 5mm/min.
3.5 Combined sealing flange connector
The structural type of pipe-fittings that adopts two sealing methods of radial and axial
at the same time.
3.6 Expansion valve inlet and outlet flange connector
The structural type of flange connector that is dedicated to the double pipe connection
of the inlet and outlet of the expansion valve.
3.7 External muffler of pipe
The metal cavity cylinders that are connected in series in the pipeline, which can
suppress the noise transmission in the pipe by changing the cross-sectional area of
the pipeline, the direction of the flow channel, and the partial volume, are usually
connected in series in the metal pipe by welding.
3.8 Radial sealing
It is one of the sealing methods. The circular elastic seal component that is installed in
the sealing groove on the pipe end uses the system's own pressure or external
pressure to fill the radial gap of the connecting surface to block the mutual flow
between the internal and external media; thereby, play a sealing role.
3.9 Axial sealing
It is one of the sealing methods. The circular elastic seal component is compressed
and deformed in the axial direction by assembling the pre-tightening force, and pressed
tightly on the connecting surface to block the mutual flow between the internal and
external media; thereby, playing a sealing role.
5 General Requirements
5.1 Appearance
The appearance of pipe-fittings and pipes shall be free of defects that affect strength
and performance such as cracks, damage, deformation, oxide scale, etc. The sealing
surface shall be free of scratches, dents, corrosion spots and damages that cause
leakage; and the pipe end interface shall be free of sharp angles, flashes and burrs.
5.2 Materials
The materials that are used to make the parts specified in this Standard shall be
determined through negotiation between the supplier and the purchaser; and the
properties of the used materials shall meet the requirements of this Standard.
The used materials shall meet the requirements for prohibited substances specified in
GB/T 30512.
5.3 Requirements for corrosion resistance
Test according to GB/T 10125. After the aluminum alloy pipes satisfy the neutral salt
spray test for at least 480h, the high-pressure pipes shall be kept under pressure of
3.53MPa for 3min without leakage; while the low-pressure pipes shall be kept under
pressure of 1.08MPa for 3min without leakage. After surface treatment, the steel pipes
shall satisfy at least 96h of neutral salt spray test without red rust; the high-pressure
pipes shall be kept under pressure of 3.53MPa for 3min without leakage; and the low-
pressure pipes shall be kept under pressure of 1.08MPa for 3min without leakage, or
it shall be determined by both parties.
5.4 Connecting thread standard
The tooth profile of all connecting threads shall comply with the provisions of GB/T 192;
the size of threads shall comply with the provisions of GB/T 196; the tolerance of male
threads shall meet the requirements of 6g specified in GB/T 197; and the tolerance of
female threads shall meet the requirements of 7H ...