1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW14873 Outdoor Weathering of Automotive Exterior Materials Copyright 2011 General Motors Company All Rights Reserved September 2011 Originating Department: North American Engineering Standards Page 1 of 9 1 Scope Note: Nothing in this standard superc
2、edes applicable laws and regulations. Note: In the event of conflict between the English and domestic language, the English language shall take precedence. 1.1 Purpose. This standard describes the procedures for evaluating the outdoor weathering properties of materials used on the exterior of the ve
3、hicle. These include paint materials, miscellaneous finishing materials for components or assemblies, and abrasion resistant optical finishes for lenses. 1.2 Foreword. Not applicable. 1.3 Applicability. Not applicable. 1.4 Specimen exposure should duplicate the most severe conditions that may occur.
4、 Unless otherwise indicated by the responsible engineer, Procedure 1 is used for all paint materials (liquid, powder or laminated films); Procedure 2 is used for applied parts and components and special paint or coating evaluations; and Procedure 3 is used for clear lens coatings. There will be no s
5、ubstitution of other types of exposure apparatus from that specified by the responsible engineer. 1.5 Procedure 1: Black Box exposure at a fixed angle of 5 degrees from horizontal facing due south. The paint or coating is applied to 100 300 mm metal or plastic panels for exposure. Flexible test samp
6、les or small samples such as emblems may be mounted to metal panels by any method which will ensure that they remain attached throughout the specified exposure period. 1.6 Procedure 2: Special Tests. These are established on an as-needed basis by the responsible engineer to duplicate end-use conditi
7、ons. Examples are in-service position of large assemblies or components that cannot be accommodated on the black box; evaluation of coatings or metal treatments (anodizing, chrome plating, etc.) at exposure angles other than 5 degrees south; use of different types of exposure racks and conditions (i
8、.e., 45 degrees south plush salt water spray to duplicate corrosion conditions, or open rack exposure as described in SAE J1976). Other examples are test apparatus that track the sun with mirrors with/without additional water spray. 1.7 Procedure 3: Open Rack (direct weathering) at 45 degrees to the
9、 horizontal facing south. Requires 3 year weathering of plastics materials, used for optical lenses and reflectors of motor vehicle lighting equipment, as specified in the Outdoor Exposure Test specified in 49 CFR 571.108. 2 References Note: Only the latest approved standards are applicable unless o
10、therwise specified. 2.1 External Standards/Specifications. 49 CFR 571 ASTM D1654 ASTM D523 ASTM D4214 ASTM D610 SAE J576 ASTM D714 SAE J1545 ASTM D1474 SAE J1976 2.2 GM Standards/Specifications. 9982075 Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for
11、 ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14873 Copyright 2011 General Motors Company All Rights Reserved September 2011 Page 2 of 9 3 Resources 3.1 Facilities. Not applicable. 3.2 Equipment. 3.2.1 Black Box. Details and drawing
12、s per SAE J1976. The box must be painted with flat black high temperature paint. Boxes shall be fitted with a 64 mm shield to provide an unexposed area on the test piece. Boxes should be placed on supports approximately 1.2 m (4 ft) above the ground. Rack location should be on a clean surface, such
13、as a lawn or a hard surface such as concrete or gravel that is typical of the exposure location. Racks should be away from trees and shrubs that could shade the panels or attract birds and insects that could damage test specimens. 3.2.2 General Exposure Racks. For Procedure 2 (see 1.6), general expo
14、sure racks, as described in SAE J1976, are designed to accommodate any samples, such as odd shapes and sizes, assemblies and other components. 3.2.3 Open Rack. These are standard panel racks described SAE J1976 used for Procedure 3 (see 1.7) and for designated specimens or coatings per Procedure 2 (
15、see 1.6). Note: Black boxes, panel racks and general usage racks are available from William Harrison Company, 4595 East 10th Court, Hialeah, FL 33013. 3.3 Test Vehicle/Test Piece. 3.3.1 Instrumentation. 3.3.1.1 Tristimulus Colorimeter or Spectrophotometer. Must meet the requirements of SAE J1545. 3.
16、3.1.2 Gloss Meter. Must meet the requirements of ASTM D523. Report measurement angle and reading. 3.3.1.3 DOI Meter (Distinctness of Image). Report values. 3.3.1.4 Indentation Hardness Tester. Must meet the requirements of ASTM D1474, Method A. Report Knoop Hardness. 3.3.1.5 Instrumentation, Climato
17、logical. Instrumentation shall be located in the immediate area of the exposure racks. Data should be recorded daily and be available as requested. 3.3.1.5.1 Solar radiation, total ultraviolet (TUV) 290 to 385 nm as measured by a total ultraviolet radiometer (TUVR) or equivalent (available from Eppl
18、ey Laboratories, 12 Sheffield Avenue, Newport, RI 02840). Reporting shall be in MJ/m2. 3.3.1.5.2 Solar radiation, total (T), as measured by an 8-48 Pyranometer (WMO Class 2) or Precision Spectral Pyranometer (PSP), (World Meteorological Organization (WMO) Class 1), or equivalent (available from Eppl
19、ey Laboratories, 12 Sheffield Avenue, Newport, RI 02840). Reporting shall be in MJ/m2. 3.3.1.5.3 Ambient temperature (daily maximum and minimum). Measurement shall be in qC. 3.3.1.5.4 Daily maximum and minimum panel temperature measured at 5 degree; South Black Box and 5 degree South Open Rack on pa
20、inted Black (WA8555) and White (WA8554) panels. Panels must have minimum gloss and Distinctness of Image (DOI) of 80. Any prime and topcoat technology is satisfactory, as long as color, gloss, and DOI are maintained to standard. Temperature must be checked on both steel and 3 mm thick plastic panel.
21、 Unless otherwise specified, use Phase Alpha Sheet Molding Compound (SMC) as the plastic substrate. Thermocouples are T-type (copper/constantan) embedded just under the paint surface. For steel panels, solder the thermocouple to the panel prior to painting using tin/lead solder. For plastic panels,
22、drill through the back, to within 250 to 450 Pm but do not break through the surface. Epoxy the thermocouple in place. Note: Panels must be replaced as required to maintain original gloss, DOI and color match. 3.3.1.5.5 Relative humidity (daily maximum and minimum). 3.3.1.5.6 Total time of wetness o
23、n both black and white panel, steel and plastic substrates as described in 3.3.1.5.4. 3.3.1.6 Miscellaneous Materials. 3.3.1.6.1 Deionized or distilled water. 3.3.1.6.2 Solution of a mild liquid detergent, such as unscented liquid Ivory or Joy (or equivalent), and deionized or distilled water at a r
24、atio of 5:95. 3.3.1.6.3 Use 3M Finesse-It Number13084 (9982075 or equivalent see responsible engineer for approval). Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWI
25、DE ENGINEERING STANDARDS GMW14873 Copyright 2011 General Motors Company All Rights Reserved September 2011 Page 3 of 9 3.3.1.6.4 Natural or synthetic sponge for washing. 3.3.1.6.5 Non-scratching, lint-free, residue-free wiping cloths, such as Rymplecloth or equivalent (available from Kendall Company
26、, Industrial Fabrics Division, Boston, MA 02101). 3.4 Test Time. Not applicable. 3.5 Test Required Information. Not applicable. 3.6 Personnel/Skills. Not applicable. 4 Procedure 4.1 Preparation. 4.1.1 Test Sample Preparation. 4.1.1.1 Exposure Site Location. The exposure site for all exterior paint t
27、echnology approval and exterior color development approval will be south Florida (Miami area). The exposure site for other testing or use of this standard will be approved by the responsible engineer prior to testing. 4.1.1.2 Test Specimens. All paint or coatings for exposure on typical racks should
28、 be applied to 100 300 mm flat metal or plastic panels. For proper placement in the Black Box, panels must have 300 mm as one dimension. If plastic plaques are smaller than specified, mount them on metal panels of proper dimension, as indicated in 1.5. 4.1.1.3.1 Flat Panels. Typical exposure racks w
29、ill shield a portion of both top and bottom of test samples. Panels for paint material testing (Procedure 1) must have a 64 mm section at the top shielded from direct sunlight by the flap that is part of the exposure rack (Figure 1). For Black Box exposure, ensure that the entire rack surface is cov
30、ered with panels to maintain maximum temperatures. Non-test panels are used to fill the box if there are insufficient test samples. Any additional instructions or deviations from standard procedure will be provided by the responsible engineer to address requirements of other finishing materials. 4.1
31、.1.3.2 Parts, Components. When testing in accordance with Procedure 2, assemblies, components, or specific test materials may require an expanded metal or solid backing for support or to more closely simulate end user applications. When required, 3 mm holes may be placed 6 mm in from each corner of
32、the specimen to affix it to the rack so that it can freely expand and contract. (Size and placement of the holes may be adjusted to fit a specific sample). Specific instructions must be obtained from the responsible engineer for mounting procedures, exposure method and masking requirements. 4.2 Cond
33、itions. 4.2.1 Environmental Conditions. 4.2.2 Test Conditions. Deviations from the requirements of this standard shall have been agreed upon. Such requirements shall be specified on component drawings, test certificates, reports, etc. 4.3 Instructions. 4.3.1 Test Procedure. Unless specific instructi
34、ons are given, the following procedure will be followed for test specimens: 4.3.1.1 Clean all specimens monthly by flushing thoroughly with clean water at the end of the morning dew formation. 4.3.1.2 Prior to evaluation, thoroughly flush the entire surface of the sample with clean, clear tap water
35、to remove surface deposits which may damage the test surface during the washing process. 4.3.1.3 Wash the entire panel (or part) using a soft sponge and a mild liquid detergent, such as Ivory, Joy, or equivalent in a distilled or deionized water solution (ratio 5:95). 4.3.1.4 Rinse entire panel with
36、 clean water and dry with clean, compressed air or pat dry with a clean, lint-free, nonabrasive cloth after each exposure interval as specified in the pertinent specification (or as specified by the responsible engineer). 4.3.1.5 Panels and parts must be evaluated and the results reported. 4.3.1.6 F
37、or paint material evaluation (and other materials or parts as specified), if there is a visual difference between the masked and the unmasked area, hand polish a 50 300 mm strip from the top of the panel along the right side per Figure 2. Use a Plexiglas fixture or tape for masking and 9982075 polis
38、h (3M Finesse-It Number 13084 or equivalent product see responsible engineer approval). Rating areas are indicated in Figure 3. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,
39、-GM WORLDWIDE ENGINEERING STANDARDS GMW14873 Copyright 2011 General Motors Company All Rights Reserved September 2011 Page 4 of 9 5 Data 5.1 Calculations. Not applicable. 5.2 Interpretation of Results. Not applicable. 5.3 Test Documentation. 5.3.1 Evaluation and Rating. Both instrumental and subject
40、ive ratings are used depending on the characteristic rated. Subjective characteristics (Table 1) can be Qualitative (appearance properties); Quantitative (degree of defect); or Frequency (how many defects). When an initial rating is required, measurements must be made on the same test surface before
41、 and after exposure. The rating areas in Figure 1, Figure 2 and Figure 3 are specified for painted panels. When required for parts or other finishing materials, similar locations will be used for rating unless otherwise specified by the responsible engineer. Note: For accuracy, instrumental readings
42、 on parts must be made on flat sections. Low magnification (5 to 7X) may be used to confirm and classify defects. Table 1: Subjective Rating Scales Qualitative Quantitative Frequency 10 = Excellent/as Received 8 = Very Good 6 = Good 4 = Fair 2 = Poor 10 = No Change/as Received 8 = Slight 6 = Moderat
43、e 4 = Pronounced/Annoying 2 = Severe 10 = None 8 = Very Few 6 = Medium 4 = Medium Dense 2 = Dense Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STAN
44、DARDS GMW14873 Copyright 2011 General Motors Company All Rights Reserved September 2011 Page 5 of 9 Table 2: Appearance Changes Abbreviation Definition D F BL Y DC HC M C BR S GC Darkened. Color is darker, more intense. Faded. Color is lighter, less intense. Bleached. Color is more whitish. Yellowed
45、. Color is more yellowish. Discolored. Color is changed, such as by dirt retention. Changes may appear as streaks. Hue change. Pigment shifts in color. Mottled. Random non-uniformities, in circular pattern. Chalked Bronzed Scummed Gloss Change Table 3: Physical Changes Cracking Corrosion Surface Dis
46、tortion Miscellaneous CH - Checked CK - Cracked CZ - Crazed RI - Filliform corrosion RE - Edge corrosion R - General rusting RB - Rust blisters, scab RS - Scratch corrosion E - Etched WS - Waterspotted PI - Pimpled W - Warped SP - Separated ED - Exudation PP - Popped PH - Pinholed BL - Blistered 5.3
47、.1.1 Gloss (ASTM D523). Use instrumental readings on flat panels or parts sections. Report the average of 3 readings. On panels, report in washed area, W and in washed/polished area, WP. Report percent gloss loss when required, as defined by: 100Gloss Initial Gloss Final - Gloss Initial Loss Gloss %
48、 x On samples (curved parts, small sample) where instrumental readings cannot be taken, report gloss change as per Table 1, Quantitative Rating Scale. 5.3.1.2 Indentation Hardness (ASTM D1474A). Report Knoop Hardness (KHN) in the W area. 5.3.1.3 Color/Appearance Change. 5.3.1.3.1 Visual Evaluation.
49、On panels, compare the washed area (W) to the masked area (M) as indicated in Figure 3. Evaluate comparable areas on parts and components. For paint samples, also compare the polished area W to the shielded and masked/polished area (MP). Rate the amount of color change using the Quantitative Scale in Table 1 and the type of change per Table 2. 5.3.1.3.2 Instrumental Evaluation. Measure per SAE J1545, CIELAB, Illuminant D65, 10 degree Standard Observer, a
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