GB/T 20967-2007 PDF in English
GB/T 20967-2007 (GB/T20967-2007, GBT 20967-2007, GBT20967-2007)
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| GB/T 20967-2007 | English | 90 |
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Non-destructive testing -- Visual testing -- General principles
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Standards related to (historical): GB/T 20967-2007
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GB/T 20967-2007: PDF in English (GBT 20967-2007) GB/T 20967-2007
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 19.100
J 04
Non-destructive testing -
Visual testing - General principles
ISSUED ON. JULY 02, 2007
IMPLEMENTED ON. DECEMBER 01, 2007
Issued by. General Administration of Quality Supervision, Testing and
Quarantine;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 4
4 Pre-testing documentation ... 5
5 Direct visual testing ... 6
6 Remote visual testing ... 6
7 Personnel ... 7
8 Assessment ... 7
9 Post-testing documents ... 7
10 Records ... 8
References ... 9
Non-destructive testing -
Visual testing - General principles
1 Scope
This standard specifies the general principles for direct visual testing and
remote visual testing when using the visual testing to determine whether the
product complies with the specified requirements (e.g., surface condition of the
workpiece, alignment of the mating surface, shape of the workpiece).
This standard does not apply to the use of any other destructive or non-
destructive testing methods to carry out testing activities.
The basic rules applicable to the application of non-destructive testing as
specified in GB/T 5616 apply to this standard.
2 Normative references
The provisions in following documents become the provisions of this standard
through reference in this standard. For the dated references, the subsequent
amendments (excluding corrections) or revisions do not apply to this standard;
however, parties who reach an agreement based on this standard are
encouraged to study if the latest versions of these documents are applicable.
For undated references, the latest edition of the referenced document applies.
GB/T 5616 Non-destructive testing - Guidelines for application
GB/T 9445 Non-destructive testing - Qualification and certification of NDT
personnel (GB/T 9445-2005, ISO 9712.1999, IDT)
GB 11533 Standard for logarithmic visual acuity charts
3 Terms and definitions
The following terms and definitions apply to this standard.
3.1
Direct visual testing
Direct visual testing refers to the availability of a continuous, uninterrupted
k) Post-testing documents (see clause 9).
4.5 It shall use the actual test piece, to verify the process procedure. The test
piece shall, from the aspect of relative light reflectivity, surface structure,
contrast ratio and accessibility, be as close as possible to the workpiece to be
tested. It should verify the process procedures in the test area where it is most
difficult to distinguish. The actual test piece may be replaced by the workpiece
being tested or replaced by an approved reference system.
4.6 Changes in equipment and testing device details that do not adversely affect
the sensitivity level shall not require retesting of the verification procedure.
4.7 Image records shall be in accordance with the standards as specified in the
testing process procedures.
5 Direct visual testing
5.1 Direct visual testing is usually used for local testing. When the eye can be
placed within 600 mm from the surface of the workpiece to be tested and the
visual angle between the eye and the surface of the workpiece to be tested is
not less than 30°, it is suitable for visual testing. It may use mirror to improve
the viewing angle, it may also use magnifying glass, endoscope, optical fiber,
and the like to assist testing.
5.2 Direct visual testing can also be used at distances greater than 600 mm for
general visual testing. It shall use a suitable visual distance for testing.
5.3 The specific workpiece, part, container or its area to be tested shall, if
required, be illuminated by auxiliary lighting equipment. Generally, the minimum
illumination of general visual testing shall reach 160 lx, the minimum
illumination of local visual testing shall reach 500 lx.
5.4 In order to maximize the effectiveness of the testing, it shall consider the
following lighting requirements.
a) Use the best light direction relative to the observation point;
b) Avoid dazzling light;
c) Optimize the color temperature of the light source;
d) Use an illumination level that is compatible with the surface light reflectivity.
6 Remote visual testing
6.1 When it cannot use the direct visual testing, it may use the remote visual
testing. Remote visual testing uses visual aids, such as endoscopes and optical
fibers, to connect to a camera or other suitable instruments.
6.2 Whether the remote visual testing system is suitable for the completion of
the specified tasks shall be verified.
7 Personnel
Personnel which performs testing operations in accordance with this standard
shall meet the following requirements.
a) Be familiar with relevant standards, regulations, procedures, equipment
and procedure instructions;
b) Be familiar with the relevant manufacturing process and working
conditions of the workpiece being tested;
c) Has good eyesight and meet the requirements of GB/T 9445. In addition,
when performing general visual testing, it shall check the distance vision.
The distance vision of at least one eye shall reach the visual level of 1.0
of GB 11533, regardless of whether it is corrected or not. Vision shall be
checked at least every 12 months.
8 Assessment
Visual testing shall be assessed in accordance with the terms specified in the
acceptance criteria (e.g., product standards, contracts).
9 Post-testing documents
When required (such as product standards, contracts), it shall provide a written
test report that meets the following details.
a) Date and place of testing;
b) The method in clause 5 or clause 6 used;
c) Acceptance criteria and/or written process procedures/operation
instructions;
d) The equipment and/or system used, including parameter settings;
e) The contract or agreement referred to;
f) The name of the testing organization;
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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