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GB/T 31973-2015 English PDF (GBT31973-2015)

GB/T 31973-2015 English PDF (GBT31973-2015)

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GB/T 31973-2015: Natural weathering exposure tests for automotive non-metallic materials and parts

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.
GB/T 31973-2015
GB
NATIONAL STANDARD OF THE
PEOPLE 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 ...

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