GB/T 3452.2-2007 English PDF (GBT3452.2-2007)

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GB/T 3452.2-2007: Fluid power systems -- O-rings -- Part 2: Quality acceptance criteria
GB/T 3452.2-2007
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.100.60; 83.140.50
J 20; G43
GB/T 3452.2-2007 / ISO 3601-3.2005
Replacing GB/T 3452.2-1987
Fluid power systems - O-rings -
Part 2. Quality acceptance criteria
(ISO 3601-3.2005, IDT)
ISSUED ON. SEPTEMBER 26, 2007
IMPLEMENTED ON. FEBRUARY 01, 2008
Issued by. General Administration of Quality Supervision, Inspection
and Quarantine of the People’s Republic of China;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
Introduction ... 5 
1  Scope ... 6 
2  Normative references ... 6 
3  Terms, definitions and symbols ... 6 
4  Grades ... 9 
5  Surface condition ... 9 
6  Identification statement (reference to this Part) ... 10 
Foreword
GB/T 3452 “Fluid power systems - O-rings” is divided into 3 parts.
-- Part 1. Inside diameters, cross-sections, tolerances and size-identification code;
-- Part 2. Quality acceptance criteria;
-- Part 3. Housing dimensions.
This Part is part 2 of GB 3452.
This Part is equivalent to ISO 3601-3.2005 “Fluid power systems - O-rings - Part 3. Quality
acceptance criteria” (English).
This Part is identical to ISO 3601-3.2005 in terms of technical content; it only makes the
following editorial modifications.
-- The "quality acceptance criteria" in the standard title is modified as "appearance
quality acceptance criteria" [Translator. The English title is actually the same];
-- "this Part of ISO 3601" is modified as "this Part of GB/T 3452";
-- Use decimal point “.” to replace the “, ” which is used as decimal point;
-- The foreword of International Standard is deleted;
-- The "limiting dimensions" in 3rd column of Table 1, Table 2 and Table 3 is modified as
"symbols of imperfections size".
This Part replaces GB/T 3452. 2-1987.
Compared with GB/T 3452.2-1987, the main changes of this Part are as follows.
-- The standard title is modified as the present one;
-- Chapter "terms, definitions and symbols" is added;
-- In the grade classification, "grade CS" is used to replace "grade NZ" and "grade SZ"
in previous edition;
-- Surface imperfections limits of O-rings for different grades are listed in Table 1, Table
2 and Table 3 respectively;
-- Illustration figures of finished products for some imperfections are provided.
This Part was proposed by China Machinery Industry Federation.
This Part shall be under the jurisdiction of China Hydropneumatic Standardization
Technical Committee (SAC/TC 3).
Responsible drafting organizations of this Part. Northwest Rubber and Plastics Research
And Design Institute.
Participating drafting organizations of this Part. Zhongding Sealing Co., Ltd., Guangzhou
Mechanical Engineering Research Institute AND Wenzhou Sanhuan Rubber and Plastic
Products Co., Ltd.
Main drafters of this Part. Gao Jingru, Cai Peiliang, Cai Qi and Zhao Jingwen.
Previous versions replaced by this Part is as follows.
— GB/T 3452.2-1987.
Fluid power systems - O-rings –
Part 2. Quality acceptance criteria
1 Scope
This Part of GB/T 3452 lays down the quality acceptance criteria of O-rings used in fluid
systems, the dimensions of which are standardized in GB/T 3452.1, ISO 16031-1 and ISO
16031-2.
This Part of GB/T 3452 also defines and classifies surface imperfections on O-rings and
specifies maximum acceptable limits for these imperfections.
This Part of GB/T 3452 is also applicable to O-rings to be used in aerospace construction.
2 Normative references
The articles contained in the following documents have become this Part of GB/T 3452
when they are quoted herein. For the dated documents so quoted, all the modifications
(excluding corrections) or revisions made thereafter shall not be applicable to this Part.
For the undated documents so quoted, the latest editions shall be applicable to this Part.
GB/T 3452.1 Fluid power systems - O-rings - Part 1. Inside diameters, cross-sections,
tolerances and size-identification code (GB/T 3452.1-2005, ISO 3601-1.2002, MOD)
GB/T 17446 Fluid power systems and components - Vocabulary (GB/T 17446-1998, idt
ISO 5598.1985)
ISO 16031-1 Aerospace fluid systems - O-rings, inch series. Inside diameters and
cross sections, tolerances and size-identification codes - Part 1. Close tolerances for
hydraulic systems
ISO 16031-2 Aerospace fluid systems - O-rings, inch series. Inside diameters and
cross sections, tolerances and size-identification codes - Part 2. Standard tolerances
for non-hydraulic systems
3 Terms, definitions and symbols
For the purposes of this document, the terms and definitions given in GB/T 17446 and the
following apply.
3.1
backrind
longitudinal imperfection in which the rubber adjacent to the flash line shrinks below the
level of the moulding and has a “U”-like or “W”-like cross section with the flash frequently
being ragged or torn. See Figure 1.
3.2
combined flash
combination of offset, flash and parting line projection
3.3
inside diameter
d1
O-ring inside diameter
3.4
cross-section diameter
O-ring cross-section diameter, d2
3.5
excessive trimming
flattened and often roughened area around the inner and/or outer diameters of an O-ring
caused by the trimming process. [See Figures 2a and 2b]
3.6
flash
film-like material that extends from the parting line projection or inner and/or outer
diameters, caused by mould separation or present due to inadequate trimming. See
Figure 3.
3.7
flow mark
thread-like recess, usually curved, of very slight depth in the unflexed state, with normal
surface texture and round edge, caused by incomplete flow and knit of the material. See
Figure 4.
3.8