1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW14458 Copper-Accelerated Acetic Acid Salt Spray (CASS) Test Copyright 2011 General Motors Company All Rights Reserved November 2011 Originating Department: North American Engineering Standards Page 1 of 4 1 Scope Note: Nothing in this standard super
2、cedes 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. The Copper-Accelerated Acetic Acid Salt Spray (CASS) test is typically used to evaluate the performance of decorative plating appl
3、ied to metallic and non-metallic substrates. It has also been used to evaluate the performance of anodic coatings applied to aluminum. 1.2 Foreword. This standard establishes test equipment and test specimen requirements for conducting the CASS test. The chamber operation and test procedures are bas
4、ed on ISO 9227. Clarifications to ISO 9227 requirements are defined in this document. 1.3 Applicability. The CASS test is typically used for quality control and process control evaluations, and not for simulating field performance. 2 References Note: Only the latest approved standards are applicable
5、 unless otherwise specified. 2.1 External Standards/Specifications. ISO 9227 2.2 GM Standards/Specifications. GMW3286 2.3 Additional References. None. 3 Resources 3.1 Facilities. Laboratory (preferably with controlled ambient conditions). 3.2 Equipment. 3.2.1 Test Chamber. The apparatus shall consis
6、t of an environmental chamber, a suitable water supply conforming to ISO 9227 (section 3.1) requirements, provisions for humidification and heating of the chamber, the necessary means of control along with the ability to maintain the following environmental conditions: Chamber Temperature: 50 2 C (1
7、22 4 F). Humidity: 100% relative humidity (RH). Humidification/Bubble Tower Temperature: May be adjusted such that the specified operating conditions are met. Humidification/Bubble Tower Pressure: May be adjusted such that the specified operating conditions are met. Note: Refer to ISO 9227, Annex A
8、for schematic diagram of one possible design of test chamber. 3.2.2 Fog/Water Collection. Suitable collecting devices include glass or plastic funnels with the stems inserted into collection vessels. Funnels with a diameter of 10 cm have an area of about 80 cm2. 3.2.2.1 At least two clean fog collec
9、tors shall be placed within the exposure zone so that no drops of solution from the test specimens or any other runoff source shall be collected. 3.2.2.2 The collectors shall be placed in the proximity of the test specimens. Copyright General Motors Company Provided by IHS under license with General
10、 Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14458 Copyright 2011 General Motors Company All Rights Reserved November 2011 Page 2 of 4 3.2.2.3 Collection rates for each 80 cm2 of horizontal collection area sho
11、uld be in the range of 1.0 to 2.0 mL/h in each collector. Exposure zones for test specimens shall be established based on demonstrated conformance to the collection rate range. 3.2.2.4 The pH of the collected solution must be in the range of 3.1 to 3.3, when measured at 25 3 C. It may be necessary t
12、o adjust the pH by adding hydrochloric acid or sodium hydroxide or sodium bicarbonate solution of analytical grade. 3.2.2.5 The specific gravity of the collected solution shall be 1.025 to 1.040 when measured at 25 3 C. 3.2.3 Corrosivity of Test Chamber. Verification of the test apparatus, to determ
13、ine the repeatability of results for a specific chamber, or to establish correlation between two different chambers, may be performed at regular intervals or as agreed upon between interested parties (reference ISO 9227, section 5.4). Note: Test chamber parameters, collection rates, pH, and specific
14、 gravity shall be monitored and recorded daily (excluding weekends) during normal operation. 3.3 Test Vehicle/Test Piece. Not applicable. 3.4 Test Time (Typical). Calendar time: 1 to 5 days Test hours: 24 to 120 hours Coordination hours: 1 to 4 hours 3.5 Test Required Information. Not applicable 3.6
15、 Personnel/Skills. Not applicable 4 Procedure 4.1 Preparation. 4.1.1 Test Solution Preparation. The salt solution prepared per GMW3286 shall be the base solution for preparing the CASS solution. To prepare the CASS solution, dissolve 1 g of cupric chloride dehydrate (CuCl2 X 2H2O) per gallon (0.26 g
16、/L) of the GMW3286 salt solution. Add 5 to 6 mL of glacial acetic acid per gallon (1.3 to 1.6 mL/L) of the GMW3286 salt solution. 4.1.2 Sample Preparation. 4.1.2.1 Samples shall be suitably cleaned, if necessary, prior to exposure. The cleaning method shall be optional depending upon the nature of t
17、he surface and the type of contaminants. The cleaning shall not include the use of abrasives or solvents which may compromise the test surface. 4.1.2.2 Cut edges, backs, and other test specimen imperfections shall be suitably coated or protected per the discretion of the test engineer, or per agreem
18、ent between the test engineer and the requester, prior to the initiation of the test. 4.1.2.3 Test specimens are generally oriented in the test chamber so that the dominant test surface is exposed to the CASS fog at approximately 15 to 30 degrees from vertical. Specimens may be oriented at other ang
19、les if agreed upon by the requester and the test engineer. 4.1.3 Chamber Preparation. Prior to initiation of testing, the CASS solution and test chamber operating conditions, based on a minimum of 16 h, shall be met. 4.2 Conditions. 4.2.1 Environmental Conditions. See 3.2.1. 4.2.2 Test Conditions. D
20、eviations 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 Chamber Operation. Chamber operation shall be continuous for the specified test periods. “Continuous” tes
21、ting is defined as testing that is interrupted only to allow for the daily collection of CASS solution, to rearrange, remove, or introduce new test specimens, or to perform necessary chamber maintenance and repair. The number of interruptions shall be limited to three in any 24 h period, and shall b
22、e approximately ten minutes in duration, where feasible. 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 STANDARDS GMW14458 Copyright 2011 General Mot
23、ors Company All Rights Reserved November 2011 Page 3 of 4 4.3.1.2 Daily Chamber Activity. Record necessary parameters of chamber such as chamber temperature. Evacuate the chamber using safe operating and maintenance practices. Once chamber is evacuated, the chamber can be accessed. Collect solution
24、captured in each graduated cylinder. Add or remove samples as necessary. Samples should be placed in locations verified to be within specifications relative to solution collection rates. Restart chamber. Verify collected solution is within specification. Document solution parameters and adjust accor
25、dingly. 4.3.2 Test Duration. Duration of test shall be per the applicable product or material specification, or per agreement between the requester and test engineer. 5 Data 5.1 Calculations. Not applicable. 5.2 Interpretation of Results. Evaluations (pre-test and post-test), rating methods, and acc
26、eptance criteria shall be specified within engineering documentation which includes: Material Specifications, Vehicle Technical Specifications, Subsystem Technical Specifications, Component Technical Specifications, and Part Drawings. 5.3 Test Documentation. 5.3.1 Test Equipment. 5.3.1.1 The followi
27、ng chamber parameters should be recorded daily (excluding weekends): Chamber Temperature Humidification/Bubble Tower Temperature Humidification/Bubble Tower Pressure 5.3.2 Test Solution. The following information shall be recorded and available upon request. 5.3.2.1 Initial pH of each batch test sol
28、ution. 5.3.2.2 Initial specific gravity of each batch test solution. 5.3.2.3 The following collected solution parameters should be recorded daily (excluding weekends): pH Specific gravity 5.3.3 Test Report. Test reports should include all pertinent test information. 6 Safety This standard may involv
29、e hazardous materials, operations, and equipment. This standard does not propose to address all the safety problems 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 limita
30、tions prior to use. 7 Notes 7.1 Glossary. Not applicable. 7.2 Acronyms, Abbreviations, and Symbols. CASS Copper-Accelerated Acetic Acid Salt Spray cm centimeter h hour L Liter mL milliliter RH Relative Humidity Copyright General Motors Company Provided by IHS under license with General Motors Compan
31、yNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14458 Copyright 2011 General Motors Company All Rights Reserved November 2011 Page 4 of 4 8 Coding System This standard shall be referenced in other documents, drawings, etc., as
32、 follows: Test to GMW14458 9 Release and Revisions This standard was originated in September 2005. It was first approved by Corrosion Global Subsystem Leadership Team in April 2006. It was first published in May 2006. Issue Publication Date Description (Organization) 1 MAY 2006 Initial publication.
33、2 NOV 2011 Five year refresh of document. Converted from Test Method to Test Procedure. (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-,-,-
