1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW15287 Filiform Corrosion Test Procedure for Painted Aluminum Wheels and Painted Aluminum Wheel Trim Copyright 2013 General Motors Company All Rights Reserved January 2013 Page 1 of 7 1 Scope Note: Nothing in this standard supercedes applicable laws
2、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 defines a procedure that was developed for generating and evaluating filiform corrosion on painted aluminum wheels and painted aluminum wh
3、eel trim. This test has been used to evaluate the effectiveness of process and material changes with respect to filiform corrosion on aluminum wheels or trim. This procedure has also been used to evaluate filiform corrosion on painted aluminum body panels and parts. Unless otherwise noted, the proce
4、dure for testing these parts is identical to that used for testing wheels. 1.2 Foreword. Not applicable. 1.3 Applicability. Not applicable. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. ASTM B368 ASTM D1193 SAE
5、 J2634 2.2 GM Standards/Specifications. GMW14458 GMW14885 GMW15282 2.3 Additional References. Drawing DWO-4828 3 Resources 3.1 Facilities. Not applicable. 3.1.1 Calibration. The test facilities and equipment shall be in good working order and shall have a valid calibration label. 3.1.2 Alternatives.
6、 Alternative test facilities and equipment may also be used. However, all measuring variables as specified in this standard shall be determined correctly with respect to their physical definition. 3.2 Equipment. 3.2.1 Copper Accelerated Acetic Acid Salt Spray (CASS) cabinet per GMW14458 or ASTM B368
7、. 3.2.2 Humidity cabinet per the requirements of 4.3.1. 3.3 Test Vehicle/Test Piece. 3.3.1 Control Samples. Control samples must be included in every test to assure that the test conditions are normal. See 4.3.2 for selection and validation of the control samples. Consult GM North America (GMNA) Mat
8、erials Engineering for further guidance. 3.4 Test Time. Calendar time: 28 days Test hours: 678 hours 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 S
9、TANDARDS GMW15287 Copyright 2013 General Motors Company All Rights Reserved January 2013 Page 2 of 7 Coordination hours: 1 hour 3.5 Test Required Information. Not applicable. 3.6 Personnel/Skills. Not applicable. 4 Procedure 4.1 Preparation. Not applicable. 4.2 Conditions. 4.2.1 Environmental Condit
10、ions. 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. 4.3.1 Filiform Test Procedure. 4.3.1.1 Check the humidity cabinet
11、 for the temperature, humidity, air flow and exhaust vent settings. Correct any discrepancies from predetermined levels. Temperature 60 C 1 C. Humidity 85 C 3% Relative Humidity (RH). Air Flow six (6) to 24 m/minute (20 to 80 ft/minute) in the test area. 4.3.1.2 Control samples (reference 4.3.2) whi
12、ch have been evaluated over a period of time and have a known filiform growth rate must be tested with every batch of test samples to assure test consistency. 4.3.1.3 Mark the samples to be tested with the proper identification. Make sure that identification (ID) location will not affect test result
13、s. Preferably mark on back of sample. 4.3.1.4 Visually examine the painted surface and record any adverse conditions, such as sags, paint films porosity, scratches, etc., on the schematic drawing. Measure the paint film thickness over the area to be scribed and record this on the schematic drawing.
14、The film thickness will vary depending on the particular paint system being measured. 4.3.1.5 Scribe the painted wheel to the base metal with carbide tip scribing tool per GMW15282 or SAE J2634. The scribe must be as close to perpendicular to the machine lines on the wheel as possible. A fixture is
15、recommended (contact GMNA Materials Engineering for drawing DWO-4828, refer to Appendix A, Figure A1) in order to make a straight scribe line on the test sample. Check the scribe line, with multimeter, to assure electrical continuity from end to end. To do this, probes of the multimeter are first to
16、uched together to assure that the meter does read a completed electrical circuit. After the meter is checked, ground one of the probes to the sample, then run the other probe down the full length of the scribe. There must be electrical continuity down the full length of the scribe. If continuity is
17、not continuous, a fresh scribe must be made. This may be done on the same sample if there is at least 15 mm of separation from the old scribe. Continuous continuity will assure that the scribe exposes the base metal. Particular care must be taken to scribe through multiple layers of paint. 4.3.1.6 P
18、lace the scribed parts in the CASS cabinet such that the wheel and scribe are at an angle of approximately 45 degrees to the horizontal on a suitable non-metallic rack. 4.3.1.7 Expose the parts for 6 h 15 minutes in the CASS cabinet as described in GMW14458 or ASTM B368. The scribe must be fully exp
19、osed to the CASS fog settling on the part. The scribe should be at approximately 45 degrees to allow no puddles of the solution on the part. 4.3.1.8 Prepare a container, approximately 19 L (5 gal) in size, with a constant overflow of deionized water that meets the latest issue of ASTM D1193 (Type IV
20、). The deionized (DI) water must enter the bottom of the container to promote flushing of any contamination out of the container with the overflowing water. Dip-rinse the parts in this container. The parts should be dipped in a vertical direction and then turned slowly 90 degrees, then back 90 degre
21、es to the initial dip position. The parts are then removed in the same vertical direction. The total time for the dip-rinse procedure is 2 s to 3 s. The objective is to remove only the excess CASS solution. After approximately 25 samples have been dipped, the water in the container shall be dumped p
22、rior to proceeding with the sample rinsing procedure. 4.3.1.9 Place the parts directly into humidity cabinet, at a 45 degrees angle, for 672 h (4 weeks). Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted wi
23、thout license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW15287 Copyright 2013 General Motors Company All Rights Reserved January 2013 Page 3 of 7 4.3.1.10 In order to determine if design features are susceptible to filiform corrosion, unscribed and unrinsed samples should be exposed. This pr
24、ocedure, which is used for part (design) validation as opposed to system (coating) validation, will identify filiform prone locations such as uncovered edges and areas with inadequate paint film thickness. Any corrosion from design features must be addressed. 4.3.2 Validation of Control Samples. 4.3
25、.2.1 Test master samples, such as wheels or test panels (consult GMNA Materials Engineering for guidance when selecting a control standard), shall be obtained in quantity. Samples shall be tested to validate variation within the master sample population. Once the master sample has been validated as
26、an appropriate control sample, the remainder of the samples shall be used in subsequent testing. 4.3.2.2 The initial control sample data (from the control sample validation process described in 4.3.2.1) shall be plotted to create a control chart (with upper and lower control limits). Control samples
27、 shall subsequently be tested with each new sample group, and the control chart shall be updated upon conclusion of the testing. Unacceptable variation in control sample performance (i.e., outside the established control limits), shall disqualify the control sample and all test parts in the sample g
28、roup. 4.3.2.3 When the supply of the control samples is depleted, new control samples shall be obtained and validated in parallel with the previous reference standards. 4.3.2.4 When testing non-wheel related parts, standard painted aluminum test panels may be used in place of, or included with, stan
29、dard wheel sections or other control samples, as reference standards. 5 Data 5.1 Calculations. 5.1.1 Filiform Length Measurements. 5.1.1.1 Measure the linear filiform corrosion growth once a week and record. Samples must not be kept out of the humidity chamber for more than 15 minutes per measuremen
30、t. The cabinet should not be opened more than once per shift and not longer than 15 minutes. 5.1.1.2 Linear filiform corrosion measurements must be taken perpendicular to the scribe and not the angle from the scribe that the filiform corrosion may have grown. Measurements must be taken from the edge
31、 of the scribe to avoid including the scribe. Record the data with two (2) significant figures. 5.1.1.3 Measure the longest filament, in millimeters, from either side of the scribe (refer to Appendix A, Figure A2 for example measurement) and record as maximum filiform length. 5.1.2 Area Measurements
32、. If requested by the customer, measure the filiform damaged area (refer to Appendix A, Figure A3 for example data sheet). Contact GMNA Materials Engineering for guidance. 5.2 Interpretation of Results. 5.2.1 Acceptance Criteria. Acceptance criteria shall be specified on the engineering drawing and/
33、or in the material specification (refer to GMW14885). 5.3 Test Documentation. 5.3.1 Report the maximum filiform length for each sample. 5.3.2 Update the control chart referenced in 4.3.2.2 with the maximum filiform length for each control sample. 5.3.3 Photograph the test parts and control samples w
34、ithin 96 h to document the filiform lengths at the end of test. (Filiform will continue to grow at room temperature). Any sample data not documented by photography or actual area and length measurements shall be considered invalid. Each photograph shall include sample identification and a scale. The
35、y must be of a magnitude and focus that will allow the filiform length to be independently audited. 5.3.4 Additional data requirements (i.e., area and distribution measurements) shall be agreed upon by the customer and the test analyst. 6 Safety This standard may involve hazardous materials, operati
36、ons, 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 limitations prior to use. Copyright
37、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 GMW15287 Copyright 2013 General Motors Company All Rights Reserved January 2013 Page 4 of 7 7 Notes 7.
38、1 Glossary. Not applicable. 7.2 Acronyms, Abbreviations, and Symbols. ASTM ASTM International CASS Copper Accelerated Acetic Acid Salt Spray DI Deionized Water GMNA GM North America ID Identification RH Relative Humidity SAE SAE International 8 Coding System This standard shall be referenced in othe
39、r documents, drawings, etc., as follows: Test to GMW15287 9 Release and Revisions This standard was originated in April 2006. It was first approved by the Global Laboratory Corrosion Testing Harmonization Team in December 2006. It was first published in May 2007. Issue Publication Date Description (
40、Organization) 1 MAY 2007 Initial publication. 2 JAN 2013 2012 Refresh. (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-,-,-GM WORLDWID
41、E ENGINEERING STANDARDS GMW15287 Copyright 2013 General Motors Company All Rights Reserved January 2013 Page 5 of 7 Appendix A Figure A1: Example Scribe Fixture Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permi
42、tted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW15287 Copyright 2013 General Motors Company All Rights Reserved January 2013 Page 6 of 7 Appendix A: Continued Figure A2: Example Filiform Measurement Copyright General Motors Company Provided by IHS under license with General M
43、otors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW15287 Copyright 2013 General Motors Company All Rights Reserved January 2013 Page 7 of 7 Appendix A Continued Figure A3: Example Data Sheet Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
