GB/T 31973-2015 PDF in English
GB/T 31973-2015 (GB/T31973-2015, GBT 31973-2015, GBT31973-2015)
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| GB/T 31973-2015 | English | 130 |
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Natural weathering exposure tests for automotive non-metallic materials and parts
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GB/T 31973-2015: PDF in English (GBT 31973-2015) GB/T 31973-2015
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 43.020
T 40
Natural Weathering Exposure Tests for
Automotive Non-Metallic Materials and Parts
ISSUED ON. SEPTEMBER 11, 2015
IMPLEMENTED ON. JANUARY 1, 2016
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 5
4 Principles ... 5
5 Exposure Site ... 6
6 Equipment on Exposure Site ... 6
7 Test Specimen ... 11
8 Test Period ... 12
9 Test Procedures ... 12
10 Test Report ... 15
Appendix A (Informative) China’s Major Climate Types ... 16
Appendix B (Normative) Temperature Control and Temperature Corrected
Radiation Energy ... 17
Appendix C (Normative) Aging Definition, Appearance Inspection Items ... 20
Foreword
This Standard was drafted as per the rules specified in GB/T 1.1-2009.
This Standard was proposed by the Ministry of Industry and Information Technology.
This Standard shall be under the jurisdiction of National Technical Committee of Auto
Standardization (SAC/TC 114).
Drafting organizations of this Standard. Hainan Tropical Automobile Test Co., Ltd.,
Technical Center of China FAW Group Corporation, National Automobile Quality
Supervision and Test Center (Xiangyang), and FAW - Volkswagen Automotive Co.,
Ltd..
Chief drafting staffs of this Standard. Li Xiaoyin, Chen Haiyan, Wang Jianbing, Li
Jinghua, Yang Zhaoguo, Liu Lizhi, and Zhang Yue.
Natural Weathering Exposure Tests for
Automotive Non-Metallic Materials and Parts
1 Scope
This Standard specifies the principle, exposure site, equipment on exposure site, test
sample, test duration, test procedure, and test report of the natural weathering
exposure tests for automotive non-metallic materials and parts.
This Standard is applicable to the natural weathering exposure tests for automotive
non-metallic materials and parts.
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) are applicable to this standard.
GB/T 3511 Rubber Vulcanized or Thermoplastic - Resistance to Weathering
GB/T 3681 Plastics - Methods of Exposure to Direct Weathering, to Weathering
Using Glass-Filtered Daylight, and to Intensified Weathering by Daylight Using
Fresnel Mirrors
GB/T 6739 Paints and Varnishes - Determination of Film Hardness by Pencil Test
GB/T 8807 Test Method for Specular Gloss of Plastics
GB/T 9286 Paints and Varnishes-Cross Cut Test for Films
GB/T 9754 Paints and Varnishes - Determination of Specular Gloss of
Non-Metallic Paint Films at 20° 60°and 85°
GB/T 11186 Methods for Measuring the Color of Paint Films (All Parts)
GB/T 15596 Plastics - Determination of Changes in Color and Variations in
Properties after Exposure to Daylight under Glass, Natural Weathering or
Laboratory Light Sources
The exposure direction of exposure frame shall face the equator, namely, from south
to north. In the northern hemisphere, the front side of specimen shall face the due
south direction; in the southern hemisphere, the front side of specimen shall face the
due north direction. However, to adapt to the special test purpose, the specimen can
be placed facing any direction. The tilted angle between specimen’s exposure surface
and the horizontal surface can be realized through adjusting the tilted position of the
exposure frame. The typical exposure angle includes exposure site’s geographic
latitude angle, 90°, 45°, and 5°. If it is specially required, the exposure frame can
adopt any one angle. Exposure with back plate and black box exposure generally
adopt 5° angle. The exposure frames shall be set at the intervals that ensure sufficient
space for placing the specimen, smooth natural ventilation, and without mutual
sunlight shielding. Generally, the interval shall be no less than 1m. Automotive exterior
materials and part exposure test equipment shall be arranged at the place where the
specimen shall be avoided sunlight shielding by other objects. The lowest position of
specimen on the frame or black box against the ground shall be 0.45m, so as to avoid
touch the objects on the ground, and prevent the unexpected damage of the
specimen during the exposure period.
6.2.2 Direct exposure device
6.2.2.1 Open exposure frame (general method)
Open exposure frame is applicable to the exposure test for exterior materials, and
various shapes and dimensions of specimens. Generally, it is made of aluminum alloy.
Aluminum alloy exposure frame is suitable for different climatic regions; iron and steel
materials through proper painting treatment and wood materials without any treatment
are suitable for desert region; copper-nickel alloy material is suitable for high corrosive
regions. Exposure frame shall have sufficient length and width to install and fix the
specimens, which are ensured not to influence each other. When installing the
specimen, generally use porcelain insulation folder, plastic stopper pin, wooden frame,
wire and lining plate through corrosion-resistant treatment, fastening screws and etc.
6.2.2.2 Exposure frame with backplane (coating system)
Backplane can be made of metal sheet and wooden plywood. When the fixed holder
is made of plywood for directly installing the specimen, if the plywood occurs obvious
layering or significant fiber releasing, then it shall be replaced timely. The plywood
with medium and high density covering layer is more suitable than the plywood
without covering layer to work as the backplane, so that reduce the replacing times of
the backplane. In the dry climatic region, the thickness of applied plywood is generally
no less than 13mm; while in the subtropical or tropical climatic regions, the thickness
of applied plywood is generally no more than 19mm. Use good weather-resistance
paint to seal the edges of plywood to prevent the delamination.
6.2.2.3 Exposure black box (only applicable to the coating system)
more solar radiation.
6.2.4 Other exposure device (such as shelter shed, immersion box, and etc.)
Shielding exposure test indicates place the specimen under the shield structure to
avoid exposing under the direct exposure effect from sun, rain, snow. Shelter shed
shall be made of corrosion-resistant and weather-resistant materials, such as
aluminum alloy and others. Immersion exposure test indicates immerse part or entire
specimen into the test solution to expose; the immersing device shall be made of
corrosion-resistant and oil proof materials, or special product chamber. The structure
and dimension of these special devices shall be confirmed as per the shape and
dimension of the specimen, for the benefit of the installation and operation of the
specimen, or as per the customer’s requirements.
6.3 Measuring equipment
6.3.1 Equipment applicable to the direct exposure test include.
a) Air temperature (daily maximum or minimum value) measuring equipment;
b) Black panel temperature (daily maximum or minimum value) measuring equipment;
c) Relative humidity (daily maximum or minimum value) measuring equipment;
d) Wetting time measuring equipment;
e) Rainfall (mm) measuring equipment;
f) Measuring equipment of the total amount of solar radiation;
g) Measuring equipment of the amount of solar ultraviolet radiation (300nm ~385nm);
h) Other (such as wind direction, wind speed, and atmospheric pressure) measuring
equipment.
6.3.2 Equipment applicable to the direct exposure test under the glass include.
a) Pyranometer. It shall be installed under the glass the same as the chamber body
(the same exposure angle), the measured wavelength rang is within 295nm~2800nm,
record and provide the hourly amount of radiation, and time domain above
accumulated amount of radiation;
b) Ultraviolet radiation intensity meter. It shall be installed under the glass the same as
the chamber body (the same exposure angle), the measured wavelength rang is
within 295nm~385nm, record and provide the hourly amount of radiation, and time
domain above accumulated amount of radiation;
c) Air temperature measuring equipment in the test chamber;
8 Test Period
8.1 Setting method of test period
8.1.1 In addition to specimen types, uses, and test objectives, the setting of test
period shall also consider correctly mastering the aging process of the specimen.
8.1.2 Exposure period can be set as per time bucket (month, year), actually
receiving solar radiation of ...
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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