1、GM DAEWOO Auto & Technology EDS Engineering, GM DAEWOO Auto & Technology Standards Cr+6FREE - PHOSPHATING ON METALS EDS-M-3204 ISSUED DATE: 2005. 04. 19 REVISED DATE: 2006. 09. 22 VERSION: 2 EDS-M-3204Cr+6FREE - PHOSPHATING ON METALS PAGE: 1/4 ISSUED DATE: 2005. 04. 19 REVISED DATE: 2006. 09. 22 VER
2、SION: 2 GM DAEWOO Auto & Technology 1. SCOPE This standard specifies the phosphating for some corrosion resistance, wear resistance and lubrication on metals used by GM DAEWOO Auto & Technology Company (hereinafter referred to as the “GMDAT“). This coating system must be free of hexavalent chromium,
3、 with no hexavalent chromium in final product. ISO 3613 or GMW 3034 will be used as a reference test. 2. TYPE AND USE Table 1. Type and Use Type Specification DesignationBase metal Use Applications EPn Ferrous material, Zinc, Aluminum A little corrosion resistance Bolts, screws, springs, washersPhos
4、phating EPnL Ferrous material, Zinc, Aluminum Lubrication and wear resistance Shaft-gear Remark) Organic coating and corrosion protection oil may be treated on the phosphating to secure the high corrosion resistance. 3. QUALITY 3.1. Base metal The base metal to be coated shall be free from rust, gre
5、ase, oil, handprint and other foreign materials on the surface, and the pre-treatment method that may cause rough coating shall be avoided. 3.2. Phosphating 3.2.1. Phosphating surfaces shall exhibit crystalline structure, which is uniform and dense, and be free from untreated portion, peeling-off, o
6、r uneven adhesive portion. Also, there shall be no adhesive defects after organic coating or residue of phosphating that may cause corrosion. 3.2.2. The coating film shall provide good adhesion to the base metal. 3.2.3. In case of EPn-XV for securing the high corrosion resistance, there shall be pla
7、ted with organic coating using the barrel or rack after phosphating, and performed the curing under special conditions, and then finally treated with corrosion protection oil. The color unless otherwise specified shall be black, but the other color may be applied by agreement between purchaser and s
8、upplier. 3.3. Coating thickness and post-treatment 3.3.1. The coating thickness shall be as shown in Table 2. In principle, the maximum coating thickness is not specified. However, in case that the maximum coating thickness shall be necessary to secure dimensional accuracy as in screw threads except
9、ionally, conform to the Table 2. EDS-M-3204Cr+6FREE - PHOSPHATING ON METALS PAGE: 2/4 ISSUED DATE: 2005. 04. 19 REVISED DATE: 2006. 09. 22 VERSION: 2 GM DAEWOO Auto & Technology 3.3.2. For parts requiring corrosion resistance, post-treatment in Table 2 shall be performed as soon as possible upon the
10、 completion of coating. Table 2. Post-treatment and Coating Thickness Unit : WMinimum coating thickness (WMaximum coating thickness (WSpecification Code Post-treatmentParts in screw threads Parts in screw threads U None 10 310+5 3+5 V Oil 3 3 3+12 3+5 W Wax 3 3 3+123+5EPn X Organic coating Approxima
11、tely1 Remark 1) The post-treatment specification for code V and W shall be appropriate for the function of post-treatment (e.g. anticorrosive characteristics). If required, the material specification of oil and wax shall be indicated in drawings. 2) In case of phosphate (EPnL) treatment for lubricat
12、ion and wear resistance, the coating thickness and corrosion resistance shall be established by agreement between purchaser and supplier, and indicated on the drawings. 3.4. Corrosion resistance Corrosion resistance of coating shall conform to Table 5 according to EDS-T-7143. Table 3. Corrosion Resi
13、stance Specification Code Salt spray test (EDS-T-7143) C Specially defined (indicate on the drawing) U 2 hours - grade 1 1 hour grade 1 Remark 1)V 24 hours grade 1 W 24 hours grade 1 EPn X - Remark 1) In case of parts that have screw threads, the corrosion resistance shall be grade 1 after one hour
14、in principle. 2) In case of phosphating for lubrication and wear resistance, the corrosion resistance shall be established by agreement between purchaser and supplier, and indicated on the drawings. 3) The test piece shall be tested as received condition, that is, without washing condition for corro
15、sion testing. EDS-M-3204Cr+6FREE - PHOSPHATING ON METALS PAGE: 3/4 ISSUED DATE: 2005. 04. 19 REVISED DATE: 2006. 09. 22 VERSION: 2 GM DAEWOO Auto & Technology 4. NOTE Samples of materials or parts that follow this standard shall be approved by Technical Center before mass production & delivery. In t
16、he event of any modification from this standard, it is the sole responsibility of the supplier to inform the purchaser of all such modifications. Furthermore, the supplier shall submit the modified sample for reapproval by Technical Center before mass production & delivery. For replacement specifica
17、tion of hexavalent chromium, it shall be approved by Technical Center prior to application. The manufacturer shall only apply it to the products that are approved by Technical Center. 5. CODING SYSTEM - ,( ) (EDS-M-3204) Standard Number Coating thickness Type of post-treatment and coating thickness
18、Specification of coating e.g. EPn-XV (EDS-M-3204) : Phosphating + Organic coating + Treatment with corrosion protection oil. EPnL-(24W ) (EDS-M-3204) : For lubrication and wear resistance, Coating thickness 2 4W . 6. TEST 6.1. All tests shall be performed at 235. 6.2. Test sample 6.2.1. In principle
19、, test sample shall be taken from the products. However, in case it is impracticable to perform test on the product, a substitutive test piece shall be used by an agreement between parties concerned. 6.2.2. The test piece shall be identical to the products in the material composition, manufacturing
20、condition and surface condition before phosphating. 6.3. Measuring portion of fastener coating thickness The thickness of coated fasteners shall be measured at specific portions where corrosion resistance is required. For hexagon head bolts and screws with a length of up to 5d, center portion of the
21、 head surface or the center of the tip shall be measured(Fig. 1 and 2). For those with a length of above 5d or special parts, the measuring portion shall be determined by an agreement between the parties concerned. Recessed head bolts and screws shall be measured at the center of the tip or other pa
22、rts of the head(Fig. 2 5). Nuts shall be measured at the center of the flat portion on their side(Fig. 6). EDS-M-3204Cr+6FREE - PHOSPHATING ON METALS PAGE: 4/4 ISSUED DATE: 2005. 04. 19 REVISED DATE: 2006. 09. 22 VERSION: 2 GM DAEWOO Auto & Technology Test surface 6.4. Evaluation of the corrosion pr
23、otection Corrosion resistance of fasteners by salt spray test shall be measured at the head and thread tip for bolts and screws, and at flat portion on the side for nuts. Threads and shank shall not be considered. The female thread areas of nuts shall not be included from corrosion resistance by sal
24、t spray fog test. The surfaces of these kinds may be masked off prior to testing. 6.5. Test standards EDS-T-7136 Method of Plating Thickness Measurement EDS-T-7143 Method of Salt Spray Test ISO 3613 Chromate Conversion Coatings on Zinc, Cadmium, Aluminum-Zinc Alloys and Zinc-Aluminum Alloys - Test Methods Second Edition GMW 3034 Absence of Hexavalent Chrome 7. CROSS INDEX (REFERENCE) EDS-M-3001 Comparison table of the specification to surface treatment 8. AUTOMOTIVE RESTRICTED HAZARDOUS SUBSTANCES Materials and components of parts must comply with EDS-A-0101.
