1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW15283 Cycle - Immersion Corrosion Test for Stainless Steel Molding Materials Copyright 2011 General Motors Company All Rights Reserved September 2011 Originating Department: North American Engineering Standards Page 1 of 3 1 Scope Note: Nothing in t
2、his 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. This standard describes a test procedure intended to simulate the corrosive environment encountered by the exter
3、ior stainless steel moldings on automobiles operating where highly corrosive agents are used for winter road deicing and/or where high corrosion load near coastal regions does exist. 1.2 Foreword. Not applicable. 1.3 Applicability. Not applicable. 2 References Note: Only the latest approved standard
4、s are applicable unless otherwise specified. 2.1 External Standards/Specifications. ASTM D1193 2.2 GM Standards/Specifications. None 2.3 Additional References. None. 3 Resources 3.1 Facilities. 3.1.1 An automatic cycle timer and elevating mechanism to raise and lower test samples to specified requir
5、ements of section performance of test. 3.1.2 Heat Source. Air-circulating oven capable of maintaining 41 2 C and 30% relative humidity (RH). Airflow across samples should reach 0.25 m/s (50 ft/minute) or less. 3.2 Equipment. 3.2.1 An electrometric meter to be used for checking pH of solution. 3.2.2
6、An analytical balance with 0.1 mg sensitivity. 3.2.3 A 300 mL glass beaker that is at least 115 mm high. 3.2.4 A type J or K thermocouple. 3.2.5 A clear plastic grid 50 x 50 mm with 3 mm squares as outlined by 0.25 mm thick lines. 3.2.6 Test Solution. Sodium Sulfate (Na2So4), anhydrous, reagent grad
7、e. (Na2So4) 0.5 0.002 g. Sodium Sulfite (Na2SO3), anhydrous, reagent grade. (Na2SO3) 0.25 0.002 g. Sodium Thiosulfate (Na2S2O3), anhydrous, reagent grade. (Na2S2O3) 0.1 0.002 g. Sodium Chloride (NaCl), reagent grade. (NaCl) 52.5 0.1 g. Calcium chloride dihydrate (CaCl2 H20) reagent grade 52.5 0.1 g.
8、 Deionized water (per ASTM D1193 Type IV). Note: These reagents should be stored in a desiccator container (over calcium sulfate). 3.3 Test Vehicle/Test Piece. Not applicable. 3.4 Test Time. Not applicable. Calendar time: days Test hours: hours Coordination hours: hours 3.5 Test Required Information
9、. Not applicable. 3.6 Personnel/Skills. Not applicable. 4 Procedure 4.1 Preparation. 4.1.1 Solution Preparation. 4.1.1.1 Weigh out all reagents to the designated accuracy. 4.1.1.2 Add 25 5 mL of deionized water to a clean 3 L beaker and slowly add the first 4 reagents in the order listed (i.e., Sodi
10、um Sulfate, Sodium Sulfite, Sodium Thiosulfate, Sodium 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 GMW15283 Copyright 2011 General Motor
11、s Company All Rights Reserved September 2011 Page 2 of 3 Chloride); each reagent must be dissolved and thoroughly mixed before the next reagent is added. Label as Solution A. 4.1.1.3 Add 525 5 mL of deionized water to a clean 1 L beaker and slowly add the calcium chloride reagent. Dissolve and thoro
12、ughly mix solution until clear. Label as Solution B. 4.1.1.4 Add Solution B to Solution A with continuous stirring of the composite solution; too rapid an addition of Solution B may cause the precipitation of calcium sulfate. If a precipitate forms, gravity filter through No. 42 Whatman filter paper
13、 and discard precipitate. Filter paper in comparable quality to No. 42 Whatman filter can also be used. 4.1.1.5 Adjust the pH of the solution to 9.3 0.1 at room temperature (25 5 C) immediately after preparation (using dilute NaOH and/or dilute HCL reagent grades). Note: Shelf life of the test solut
14、ion: Store the solution in stoppered brown glass bottles. The solution must be used within 8 days following initial preparation with proper adjustments of pH at room temperature (25 5 C) being made just prior to use in testing program. 4.1.2 Sample Preparation. 4.1.2.1 Cut samples to approximately 5
15、0 x 50 mm in a shear; punch a 5.5 mm diameter hole in the top edge and polish all the edges. 4.1.2.2 Wash samples in Alconox or comparable detergent solution to achieve as near a water break-free surface as possible (i.e., scrub samples with nylon brush; soak samples 20 to 30 minutes; rescrub sample
16、s; re-soak samples 5 additional minutes using an Alconox or comparable solution 8 g/L, 43 2 C. Rinse cleaned samples, each with fresh room temperature (25 5 C) water. 4.1.2.3 Immediately examine the samples visually for any pits, scratches, roughness, or other surface defects and record. Then begin
17、test within 1 minute of cleaning. 4.2 Conditions. 4.2.1 Environmental Conditions. All testing to be conducted in the air circulating oven maintained at 41 2 C and 30% RH. Airflow across samples should be reach 0.25 m/s (50 ft/minute) or less. 4.2.2 Test Conditions. Measure the pH at room temperature
18、 (25 5 C). 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 Measure the pH before test and record. Place 300 5 mL of fresh test solution heated to 41 2 C
19、 in a 30 to 300 mL tall form beaker for each sample to be tested. Solution temperature shall be maintained at 41 2 C during the test. No solution additions are required during the test. 4.3.2 Attach the sample to the mechanical elevator by a non-metallic connector. Position it over solution beaker w
20、ithin the oven. 4.3.3 Adjust the mechanical elevator and timer to provide a complete sample immersion (2 0.2 s) in the test solution and 98 to 102 s dry off period out of the test solution. Complete cycle time, 99 to 104 s. Sample travel time between wet and dry periods shall not exceed 1 s (50 mm/s
21、 rate). 4.3.4 After the specified exposure, remove samples from test and rinse in warm tap water. Dry the samples by gently blowing off with compressed air. 5 Data 5.1 Calculations. Not applicable. 5.2 Interpretation of Results. 5.2.1 The dried panels shall be examined by the naked eye for evidence
22、of corrosion. Surface defects, pits or etch spots which have developed as a result of this test shall be considered corrosion. 5.2.2 Lay a clear plastic grid with 3 mm squares over the test panel face. Count and report all squares containing defects which are the origin of corrosion products, such a
23、s red rust stain. Disregard defects within a 3 mm width band around the edges of the panel and the pierced hole. Also, disregard the corrosion products such as red rust rundown and blue stain. 5.2.3 Acceptance criteria shall be specified within engineering documentation which includes: Material Spec
24、ifications, Subsystem Technical Specifications, Component Technical Specification, and part drawings. 5.3 Test Documentation. Document the squares containing defects as described in 5.2.2. 6 Safety This standard may involve hazardous materials, operations, and equipment. This standard does not propo
25、se 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 General Motors Company Provided by IHS under lic
26、ense with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW15283 Copyright 2011 General Motors Company All Rights Reserved September 2011 Page 3 of 3 7 Notes 7.1 Glossary. Not applicable. 7.2 Acronyms, Abbr
27、eviations, and Symbols. CaCl2 H20 Calcium Chloride Dihydrate HCL Hydroclorid Acid Na2S2O3 Sodium Thiosulfate Na2SO3 Sodium Sulfite Na2So4 Sodium Sulfate NaCl Sodium Chloride NaOH Sodium Hydroxide pH pH-value RH Relative Humidity 8 Coding System This standard shall be referenced in other documents, d
28、rawings, etc., as follows: Test to GMW15283 9 Release and Revisions This standard was originated in March 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)
29、1 AUG 2006 Initial publication. 2 SEP 2011 Five year refresh. Paragraph 1.1 “Purpose” related to possible corrosion load scenarios aligned; term deionized water incorporated instead of distilled water; paragraph 4.2.1 “Environmental Conditions” added with air flow parameters. (Corrosion Global Subsystem Leader-ship Team) Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
