BS EN 12329 pdf free download

BS EN 12329 pdf free download.Corrosion protection of metals一 Electrodeposited coatings of zinc with supplementary treatment on iron or steel.
5 Designation 5.1 General The appropriate designation according to the severity of service conditions which the coating has to withstand (see annex B) shall be used. NOTE Examples of designations are given in annex C. 5.2 Heat treatment The heat treatment designation as described in EN 1403 shall be used (see clause 6). 5.3 Supplementary treatments 5.3.1 Chromate conversion coatings The codes for chromate conversion coatings given in annex B shall be used. NOTE See annex A for more information on chromate conversion coatings. 5.3.2 Other supplementary treatments Treatments caried out after chromating to enhance corrosion resistance (sealants) or provide colour (dyes) shall be specified in the designation using the symbols given in EN 1403. NOTE See the introduction, A.2 and A.5 for more information on sealing and dyeing.
7 Requirements 7.1 General All tests (including corrosion resistance tests) shall be deferred until the expiry of a period of 24 h after the chromating process has ended. NOTE Chromate conversion coatings harden with age by gradual dehydration. They should therefore be handled carefully for the first 24 h after the treatment. 7.2 Appearance Over the significant surface, the electroplated articles shall be free from clearly visible plating defects such as blisters, pits, roughness, cracks or unplated areas. See also 4.1 d) of EN 1403:1998. Parts which have been given supplementary treatment shall be free from untreated areas on the significant surface. 7.3 Thickness 7.3.1 Minimum local thickness When tested in accordance with one of the following standards the minimum local thickness of the zinc coating on articles having a significant surface area of greater than 1 cmt shall conform to that specified in its designation: EN ISO 1463, EN ISO 2177, EN ISO 2178, EN IsO 2360, prEN ISO 3497, prEN ISO 3543. NOTE Before using the method specified in EN ISO 2177, it is necessary to remove the chromate or other supplementary treatment using a very mild abrasive, for example a paste of levigated alumina or magnesium oxide. In the case of heavy conversion coatings, the results will, therefore, be slightly low.7.3.2 Average thickness For articles having a significant surface area of less than 100 mm’, the minimum local thickness shall be deemed to be the minimum value of the average determined by the method specified in annex D. 7.4 Adhesion 7.4.1 Adhesion of zinc coating When tested by the burnishing test in accordance with EN ISO 2819 the zinc coating shall have good adhesion. 7.4.2 Adhesion of coloured chromate coating Coloured chromate coatings shall be tested in accordance with 3.6 of EN ISO 3613:1994. 7.5 Corrosion resistance When tested in accordance with the neutral salt spray (NSS) test described in ISO 9227 for the times given in Tables 1 and 2, the test surface shall remain free from red corrosion product (see Table 1) or white corrosion product (see Table 2) when examined by the unaided eye or corrected vision. Slight staining of the test surface shall not be a cause of rejection. The test surface shall comprise those parts of the significant surfaces of the test specimens that can be touched by a ball 20 mm in diameter or as otherwise specified by the purchaser (see clause 4). NOTE Red corrosion indicates corrosion of the basis metal and white corrosion indicates corrosion of the zinc coating. BS EN 12329 pdf download.