1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure SUPERCEDED GMW14728 Determination of the Resistance of Automotive Components to Sulfur Dioxide in a High Humidity Environment Do Not Use on New Programs; Replaced by ASTM G87 or DIN EN ISO 6988 Copyright 2012 General Motors Company All Rights Reserved
2、December 2012 Originating Department: North American Engineering Standards Page 1 of 3 1 Scope Note: Nothing in this standard supercedes 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.
3、 The purpose of this standard is to determine the resistance of metals, metallic and other protective coatings, normally applied to automotive components to sulphur dioxide in an environment of high humidity. The test is accelerated and carried out using sulphur dioxide injected into air saturated w
4、ith water vapour at specified temperatures. 1.2 Foreword. Not applicable. 1.3 Applicability. This test is applicable to components that are exposed to the industrial environments. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/
5、Specifications. ISO 3231 2.2 GM Standards/Specifications. None 3 Resources 3.1 Facilities. Not applicable. 3.2 Equipment. The test apparatus shall consist of the chamber design as defined in IS0 3231 3.3 Test Vehicle/Test Piece. Where possible, the test shall be conducted on complete components. The
6、 test can also be conducted on specially prepared test panels of a minimum area 250 cm2. 3.4 Test Time. Exposure time and test procedure must be specified by reference document or test requestor. Calendar time: 1 to 6 days Test hours: 24 to 144 hours Coordination hours: to 1 hour 3.5 Test Required I
7、nformation. Not applicable. 3.6 Personnel/Skills. Not applicable. 4 Procedure 4.1 Preparation. 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 STANDAR
8、DS GMW14728 Copyright 2012 General Motors Company All Rights Reserved December 2012 Page 2 of 3 4.1.1 Test Sample Preparation. Where the size and/or shape of the component prohibit testing of a complete component, test pieces shall be cut from the component. Such test pieces shall have the largest p
9、ossible size and shall be cut such that the edges are not heavily mechanically deformed nor subjected to excessive temperatures. All cut edges shall be protected in a suitable manner (e.g., with adhesive tapes, protective paints etc.) during test. Any selective portion of a test piece not requiring
10、testing shall be suitably protected with a material which does not affect or is affected by the test medium. For initial sample approval and arbitration purposes, at least three test pieces shall be tested. For routine quality control, at least one test piece shall be tested. Metallic and metal coat
11、ed test pieces shall be degreased and cleaned using a non-chlorinated solvent (e.g., Xylene of Petroleum Spirit). The cleaning shall be carried out immediately prior to testing. Anodized aluminium test pieces shall be cleaned with acid free dlchloromethane prior to testing. Test pieces with protecti
12、ve coatings other than those defined above shall not be cleaned prior to testing. 4.1.2 Test Duration Determination. The test periods for this test are defined below: Code: Test Period (hours/cycles) A: Specifically defined B: 24 h or 1 cycle C: 48 h or 2 cycles D: 72 h or 3 cycles E: 96 h or 4 cycl
13、es F: 120 h or 5 cycles G: 144 h or 6 cycles 4.1.3 Test Solution Determination. The material to be tested shall determine which of the three sulfur dioxide volumes listed below: Code: Volume of Sulfur Dioxide 2.0 L 1.0 L 0.2 L Note 1: Volume of Sulfur Dioxide is per 300 L of test chamber capacity. 4
14、.2 Conditions. 4.2.1 Environmental Conditions. Not applicable. 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. The test apparatus shall
15、 be prepared for use according ISO 3231 The test cabinet shall be sealed, injected with sulphur dioxide (as specified based on concentration code) and the cabinet temperature shall be maintained at 40 C 3 C allowing 1.5 h of ramp time for a total of 8 h (including ramp time). 4.3.1 The test cabinet
16、is then vented and temperature maintained at 23 C 5 C allowing 1.5 h of ramp time for a total of 16 h (including ramp time). One (1) cycle consists of 24 h. At the completion of each cycle, the test pieces shall be removed for interim examination. Furthermore, the reservoir shall be emptied, cleaned
17、 if necessary and then refilled with the specified volume of test solution and test pieces put back into the test cabinet. The cycle shall be repeated for the designated test duration. At the completing the specified test duration, the test pieces shall be removed from the cabinet and, unless otherw
18、ise stated, washed with distilled/deionized water and allowed to dry at 23 C 5 C for evaluation. 5 Data 5.1 Calculations. Not applicable. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license fr
19、om IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14728 Copyright 2012 General Motors Company All Rights Reserved December 2012 Page 3 of 3 5.2 Interpretation of Results. 5.2.1 Evaluation. Visual evaluation of the test pieces or components shall be carried out immediately after the specified test per
20、iod and appropriate grading allocated according to the following criteria. Grade 1: No change of surface. Grade 2: Change of surface appearance allowed but no corrosion of the base material. Grade 3: Specially defined. 5.2.2 Acceptance Criteria. Acceptance criteria shall be specified on the engineer
21、ing drawing or in the material specification. 5.3 Test Documentation. The test documentation shall contain at least the following information: 5.3.1 All details necessary to identify the coating tested (type of coating, thickness, etc.) 5.3.2 A reference to this standard. 5.3.3 Conditions and durati
22、on of the test, including the volume measured at atmospheric pressure of sulfur dioxide to be used (0.2 L, 1.0 L, and 2.0 L). 5.3.4 Results of the evaluation. 6 Safety This standard may involve hazardous materials, operations, and equipment. This standard does not propose to address all the safety p
23、roblems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 7 Notes 7.1 Glossary. Not applicable. 7.2 Acronyms, Abbreviations, and Symbols. Not appl
24、icable. 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Test to GMW14728 9 Release and Revisions This standard was originated in October 2005. It was first approved by the Global Corrosion Harmonization Team in December 2006. It was first published i
25、n August 2007. Issue Publication Date Description (Organization) 1 AUG 2007 Initial publication. 2 DEC 2012 Superceded by ASTM G87 or DIN EN ISO 6988. (Corrosion Global Subsystem Leadership Team) Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
