1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW15284 Spot Test for Etch Susceptibility of Stainless Steel Copyright 2011 General Motors Company All Rights Reserved September 2011 Originating Department: North American Engineering Standards Page 1 of 2 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. This standard describes a test procedure to be followed when conducting spot test on cold rolled stainless steel. The object of th
3、e test is to determine etch susceptibility on the stainless steel. 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 D1193 2.2 GM Standards/Spec
4、ifications. None 2.3 Additional References. None. 3 Resources 3.1 Facilities. Not applicable. 3.2 Equipment. 3.2.1 Test Solution. The following reagent grade chemicals are dissolved in 200 ml of deionized water: x 10 g ferric chloride (hydrated) (Fe3CI 6H20) x 5 g sodium chloride x 2.5 mL hydrochlor
5、ic acid (concentrated) x Deionized water (per ASTM D1193 Type IV) Note: This test solution must be stored in a stoppered glass container and used within 1 month of initial mixing. 3.2.2 Solvent. Suitable organic solvents or detergents for cleaning specimens. 3.2.3 Drying. A sufficient amount of soft
6、 clean cloth or paper towels for drying specimens. 3.2.4 Dropper. A clean glass dropper. 3.2.5 Container. A clean glass container (for immersion testing when required). 3.3 Test Vehicle/Test Piece. Coupons of incoming material or parts manufactured from stainless steel are satisfactory for the test.
7、 For Production Part Approval Process, actual production parts are to be used. 3.4 Test Time. Not applicable. Calendar time: days Test hours: hours Coordination hours: hours 3.5 Test Required Information Not applicable. 3.6 Personnel/Skills. Not applicable. 4 Procedure 4.1 Preparation. The stainless
8、 steel surface shall be cleaned of oil, wax, dirt or buffing compound by means of organic solvents or detergents, followed by a tap water rinse and drying with a paper towel. 4.1.1 Wash samples in Alconox or comparable detergent solution to achieve as near a water break-free surface as possible, i.e
9、 scrub samples with nylon brush; soak samples 20 to 30 minutes; re-scrub samples; re-soak samples 5 additional minutes using an Alconox solution 8 g/L, 43 2 C. Rinse cleaned samples, each with fresh room temperature 25 5 C water. 4.1.2 Immediately examine samples visually for any pits, scratches,
10、roughness or other defects and record. Then begin test again within 1 minute of cleaning. 4.2 Conditions. The sample and test temperature solution should be maintained between 25 5 C during testing. 4.2.1 Environmental Conditions. Not applicable. 4.2.2 Test Conditions. Deviations from the requiremen
11、ts of this standard shall have been agreed upon. Such requirements shall be specified on component drawings, test certificates, reports, etc. 4.3 Instructions. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permit
12、ted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW15284 Copyright 2011 General Motors Company All Rights Reserved September 2011 Page 2 of 2 4.3.1 Application of Solution. Test solution must be applied in the following way: Apply a drop with a clean glass dropper in a 6 to 8 mm
13、diameter wax ring made with a china pencil or comparable wax marking device. 4.3.2 Duration of Test. The solution shall be left in contact with the surface of the sample for 5 minutes. The solution shall be removed by rinsing with flowing tap water, and the surface dried with forced air or by light
14、rubbing with a clean soft cloth or paper towel. The wax ring shall be removed with an organic solvent. Test-to-failure should be done in additional 5 minute increments. 5 Data 5.1 Calculations. Not applicable. 5.2 Interpretation of Results. 5.2.1 Etch susceptibility is determined by visual compariso
15、n of the test spot with untested surface areas. Etch susceptibility is indicated by various degrees of dulling, frosting, pitting, graying, or any other type of visible permanent change in luster of the test area. Samples should be viewed under daylight as well as fluorescent lighting. 5.2.2 Accepta
16、nce criteria shall be specified within engineering documentation which includes: Material Specifications, Subsystem Technical Specifications, Component Technical Specification, and Part Drawings. 5.3 Test Documentation. Document the etch susceptibility as described in 5.2.1. 6 Safety This standard m
17、ay involve 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 regulato
18、ry limitations prior to use. 7 Notes 7.1 Glossary. Not applicable. 7.2 Acronyms, Abbreviations, and Symbols. Not applicable. 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Test to GMW15284 9 Release and Revisions This standard was originated in Marc
19、h 2005. It was first approved by the Global Laboratory Corrosion testing Harmonization Team in April 2006. It was first published in August 2006. Issue Publication Date Description (Organization) 1 AUG 2006 Initial publication. 2 SEP 2011 Five year refresh. Term “distilled water” replaced by deionized water; Paragraph 3.2.1. ASTM D1193 Type IV for deionized water added. (Corrosion Global Sub-system 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-,-,-
