1、 WORLDWIDE ENGINEERING STANDARDS Material Specification GMW14674 Organic Coating for Cast Iron Parts Copyright 2012 General Motors Company All Rights Reserved September 2012 Originating Department: North American Engineering Standards Page 1 of 4 1 Scope This standard covers the performance requirem
2、ents for organic paint finishes to underbody/hood parts for cast iron parts. 1.1 Material Description. This coating can be an organic electrostatically applied powder epoxy paint or liquid applied paint. 1.2 Classification. Type A. Electrostatic Applied Epoxy Powder Coating. Only epoxy materials are
3、 approved for this type coating. Other paint technologies may be suitable and shall require validation to assure conformance to durability, machinability and topcoating specifications. Type B. Liquid Applied Paint Film. 1.3 Typical Applications. This coating is suitable for medium to large parts in
4、underhood and underbody applications where protection from ultraviolet (UV) light exposure is not required. The resultant paint film is intended to provide cosmetic corrosion resistance to exterior surfaces of cast iron components, e.g., cylinder heads and blocks. 2 References Note: Only the latest
5、approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. ISO 105-F09 ISO 9227 ISO 1463 ISO 17025 2.2 GM Standards/Specifications. 9985809 GMW14729 GMW3059 GMW14829 GMW14700 GMW15282 2.3 Additional References. TMC003 Material Safety Data Sheet guidance docu
6、ments (available at ). 3 Requirements 3.1 Appearance. The cured paint film shall be free from inclusions and runs. The color shall be black or gray as defined on the drawing. 3.2 Coating Thickness. Coating thickness is specified for both electrostatic applied Epoxy Powder and liquid coatings: Type A
7、: Epoxy Powder Coating: 100 +50/ -25 m. Type B: Liquid Applied Coating: 50 m minimum. Note: For referee purposes, the coating thickness shall be determined by microscopic examination of cross sections taken perpendicular to significant surfaces per ISO 1463. Note: Overspray is allowed as designated
8、on component drawings. 3.3 Adhesion. Crosshatch tape adhesion test per GMW14829. Rating 0 and 1 as delivered and after 96 h humidity testing per GMW14729, Option A or B. This test requirement shall apply to all component locations that can physically be tested. 3.4 Corrosion and Creepback Resistance
9、. 3.4.1 Coated parts shall show no evidence of blistering, separation, softening, discoloration or other appearance changes at the end of exposure per ISO 9227 for hours indicated. Maximum allowable creep back is 3 mm for Type A and 2 mm for Type B coatings per GMW15282. Less than 10% of coated surf
10、ace shall be corroded (exclusive of scribe area and/or within 2 mm, of sharp edges). Type A: 168 h Type B: 96 h Note: For Type B, this test shall be performed on parts in the as-received condition and after exposure for 120 h in a drying oven at +100 C 3 C. 3.4.2 Significant surfaces for test evalua
11、tion shall be all exposed surfaces unless otherwise specified on the drawing. 3.5 Chip Resistance. Test coated part per GMW14700, Method A (or B) and C. Test at room temperature and -18 C. A minimum rating of 7 is required. 3.6 Humidity Resistance. Expose coated parts per GMW14729, Option A or B for
12、 96 h. After 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 GMW14674 Copyright 2012 General Motors Company All Rights Reserved September 20
13、12 Page 2 of 4 exposure, the coating shall show no blistering, separation (no loss of adhesion), softening, discoloration or other appearance changes. 3.7 Chemical Resistance. After exposure to the following fluids, the coating shall show no blistering, separation (no loss of adhesion), softening, d
14、iscoloration or other appearance changes. 3.7.1. Water. Completely immerse coated parts in potable water for 24 h 1 h at 63 C 2 C. 3.7.2. Motor Oil Resistance. The coated part shall be immersed in SAE 5W30 motor oil, removed and drained for a few minutes, then placed in a drying oven at 100 C 3 C fo
15、r 24 h 1 h. 3.7.3. Fuel Resistance. Coated parts shall be immersed in commercial grade E10 gasoline, E85 gasoline, and diesel fuel 24 h 1 h at room temperature. 3.7.4 Solvent Resistance. Coated parts shall be subjected to ten double rubs with soft cheesecloth (cotton rubbing cloth to ISO 105-F09) sa
16、turated with 60% isooctane/40% toluene. 3.7.5. Completely immerse coated parts in a 50% solution of extended life coolant (9985809) and potable water for 24 h 1 h at 63 C 2 C. 3.8 Sensor Compatibility. Coating material must not degrade the response time or functioning of the oxygen sensors or any ot
17、her engine sensor. Coating composition shall be free of compounds harmful to such sensors. The GM sensor Technical Specialist shall be contacted for review of any new formulation with sensor suppliers. 3.9 Topcoat Compatibility (Type A Only). Coating shall not contain film formers, resins or additiv
18、es detrimental to topcoat adhesion. Painted test panels shall be topcoated with finishes commonly used by engine Marinizers. Topcoated panels representative of the Marinizer coating process shall satisfactorily pass GMW14829, cross-cut tape adhesion test (topcoat to powder) after exposure to 96 h of
19、 condensing humidity per GMW14729, Option A or B. Note: Satisfactory panel performance and topcoat compatibility subject to GM Powertrain evaluation and approval. 3.10 Process and Machining Compatibility. Coatings shall be sufficiently cured prior to machining to avoid any damage during subsequent o
20、perations and cleaning processes. A production run of parts shall be monitored to ensure that paint machinability does not adversely affect tool life, washer performance, or appearance, etc., and that common plant cutting fluids, cleaners, solvents, etc., which contact components do not adversely af
21、fect coating appearance or performance. 4 Manufacturing Process The coating process, including pre-treatment (cleaning), coating, and post-treatment shall be performed by one company in one facility. The equipment, process controls, chemicals, and location used must remain the same for regular produ
22、ction. This includes pre-treatment (such as cleaning) and post-treatment. These operations cannot deviate without prior approval by GM. For each production lot of coated parts, the applicator shall supply a certificate to their customer with the following information: This specification number. Appl
23、icator name and address. Coating system used. Part number. Date(s) the parts were coated. Coating thickness. The applicator shall keep the certificates for a minimum of 5 years. 5 Rules and Regulations 5.1 Legal Regulations. All materials must satisfy applicable laws, rules, regulations and recommen
24、dations valid in the country of usage. 5.2 Language. In the event of conflict between the English and domestic language, the English language shall take precedence. 5.3 Inspection and Rejection. Samples of components or materials released to a GM material specification shall be tested for conformity
25、 with the requirements of this material specification and approved by the responsible Engineering department prior to commencement of delivery of bulk supplies. A new approval must be received for any changes, e.g., properties, manufacturing process, location of manufacture, etc. If not otherwise ag
26、reed, all testing and documentation normally required for initial release must be completed. It is the responsibility of the supplier to inform the customer in a timely manner, without solicitation, and to include documentation of all modifications of materials and/or processes and to apply for a ne
27、w release. If not otherwise agreed, all release tests shall be repeated and documented by the supplier prior to commencement of delivery of non-conforming bulk supplies. In individual cases, a shorter test can be Copyright General Motors Company Provided by IHS under license with General Motors Comp
28、anyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14674 Copyright 2012 General Motors Company All Rights Reserved September 2012 Page 3 of 4 agreed to between the responsible Engineering department and the supplier. 5.4 Materi
29、al Safety Data Sheets/Safety Data Sheets (MSDS/SDS). For new product submissions, or when a change in chemical composition of an existing product has occurred, a complete copy of the Material Safety Data Sheet/Safety Data Sheet must be submitted in compliance with the Globally Harmonized System of C
30、lassification and Labeling of Chemicals (GHS) requirements or other country-specific MSDS/SDS requirements. In addition, product MSDS/SDS submissions must be in compliance with specific country General Motors TMC003 Material Safety Data Sheet/Safety Data Sheet guidance documents where available. 5.5
31、 All materials supplied to this standard must comply with the requirements of GMW3059, Restricted and Reportable Substances for Parts. 6 Approved Sources Materials supplied to this specification must be approved by General Motors. A list of approved materials can be found in MATSPC. This GM Material
32、 File is provided to third parties to reduce redundant testing of materials. If approved material already listed is used, the part supplier can use GM Material File reference for Production Part Approval Process (PPAP) material approval. If the decision is made to use a not yet approved material, co
33、ntact the responsible Materials Engineer for detail on the approval process. The material approval process must be completed prior to PPAP start date of the part supplied to General Motors. 7 Notes 7.1 Glossary. MATSPC: Global repository of GM approved materials for corresponding GM Engineering Stan
34、dards. 7.2 Acronyms, Abbreviations, and Symbols. AIAG Automotive Industry Action Group GHS Globally Harmonized System of Classification and Labeling of Chemicals MSDS Material Safety Data Sheet NSS Neutral Salt Spray PPAP Production Part Approval Process SDS Safety Data Sheet UV Ultraviolet 8 Coding
35、 System This standard shall be referenced in other documents, drawings, etc., as follows: Material per GMW14674, Type (A or B), color (black or gray) 9 Release and Revisions This standard was originated in October 2005. It was first approved by the Global Finishes & Coatings Team in May 2006. It was
36、 first published in May 2007. Issue Publication Date Description (Organization) 1 MAY 2007 Initial publication. 2 SEP 2012 Five year refresh of standard. Update of chemical resistance reference specifications. Editorial changes. (Finishes & Coatings Global Subsystem Leadership Team) Copyright Genera
37、l 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 GMW14674 Copyright 2012 General Motors Company All Rights Reserved September 2012 Page 4 of 4 Appendix A: Ch
38、emical Approval Test Requirements Test samples must be coated on a regular production line with the intended chemistry. No special handling and processing allowed. All testing must be performed by independent ISO 17025 accredited laboratory unless otherwise authorized by GM. Official reports (in ele
39、ctronic format) are required. All after-test samples must be submitted together for review. Since certain test parts (such as after corrosion testing) will continue to degrade after end of test, it is important to plan ahead. For new chemical systems, submit technical data sheet and a “dry film“ MSD
40、S for evaluation for potential hazardous material. Section 3 specific notes: 3.1 Submit coated samples for review. 3.2 thru 3.7. A minimum sample size of 5 for each test/exposure. Submit all samples after test. The coating thickness must be typical of regular production. 3.8 The dry film MSDS will b
41、e reviewed by GM Engineering for sensor compatibility. Additional information may be requested. 3.9 Submit all after-test parts. 3.10 Production trial run of intended application at GM plant will be arranged after all other requirements are fulfilled. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
