Surface Finish Standard

Maryland Metrics: Standard Platings - Surface Coatings

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MARYLAND METRICS: Technical Data Chart

STANDARD STANDARD PLATINGS: SURFACE S URFACE COATINGS ISO : 4042 (EN ISO 4042) 4042) Electroplated Electropl ated coatings DIN : 267 Part 9 Electroplated coatings/Riv coatings/Rivestimen estimentiti elettrolitici/Revêtement elettrolitic i/Revêtement électrolytiques/ Revestim Revesti mientos electrolìticos/Elektrol electrolìticos /Elektrolyti ytische sche Überzü Überzüge ge Code system/Sistema di codifica/Systême de codification/sistema de codificaciòn/Kodifizierungssystem 1. Scope and field of applicati application on These These technical conditions are in particular related to threaded fasteners (mainly (mainly bolts and nuts), but are also applicable to the whole range of mechanical fasteners. 2. Electropl Elect roplated ated coatings coa tings An electrolytically electrolyti cally applied applied coating shall be defined defined as a protective metallic metallic layer lay er being deposited deposited onto the surface of metal articles by immersing these parts in an aqueous solution through which an electrical current is passed. Note: The use of the nomenclature “galvanizing” for this treatment is not correct. This This information information on electroplated coatings correspond corres pondss with wit h DIN 267 Part 9 and ISO 4042. 3. Code system The The electroplated coatings of mechanical mechanical fasteners fast eners are designated designated by a code consisting consis ting of a combination combination of two capital letters and a number. This This callout system sys tem is built built up as follows: – a capital c apital letter for the coating c oating metal metal (Table (Table 1) – a number for the minimum layer thickness (coating structure) (Table 2) – a capital letter for the degree of gloss and after-treatment after-treatment (Table (Table 3) Table 1. Coating metal Code letter A B C D E F G

Coating metal Sy mbol Zinc Zn Cadmium Cd Copper Cu Brass CuZn Nickel Ni Nickel-chrome 1) NiCr Copper-nickel CuNi Copper-nickel-chrome H CuNiCr 1) J Tin Sn K Copper-tin CuSn L Silver Ag N Copper-silver CuAg P Zinc-Nickel 3) ZnNi Q Zinc-Cobalt 3) ZnCo R Zinc-iron 3) ZnFe 1) Thickness of chrome layer 0,3 µm 3) Not in ISO 4042

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Table 2. Mini inimum layer yer thickn ckness (coa coating str structu cture) Layer thickness (coating structure) in µm Code number 1 coating metal 0 1) – 1 3 2 5 3 8 4 12 5 15 6 20

2 coating metals – – 2+ 3 3+ 5 4+ 8 5+10 8+12

7 2) 25 10+15 8 2) 32 12+18 9 2) 40 16+24 3) 1) Code number 0 applies to screw threads below M 1.6, where no specific layer yer thickness can be specified. 2) Does not apply to threaded components. 3) Not in ISO 4042

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Table 3. Degree of gloss and after-treatment Degree of Chromating in accordance with DIN 50 941 Self-color of chromate layer Codeletter gloss Process group passivation by chromate mt (dull) A (mat) none 1) none mt (dull) B (mat) B bluish to bluish iridescent 2) mt (dull) yellowish glistening to yellowishC (mat) C brown,iridescent mt (dull) D (mat) D olive green to olive brown E bk (bright) none 1) none F bk (bright) B bluish to bluish iridescent 2) yellowish glistening to yellowishG bk (bright) C brown,iridescent H bk (bright) D olive green to olive brown J gl (glossy) none 1) none K gl (glossy) B bluish to bluish iridescent 2) yellowish glistening to yellowishL gl (glossy) C brown,iridescent M gl (glossy) D olive green to olive brown hgl (high N gloss) none – bel P (optional) B, C or D 3) at manufacturer's discretion as for process group B, C or D mt (dull) R (mat) F brownish black to black S bk (bright) F brownish black to black T gl (glossy) F brownish black to black U all finishes no chromate treatment 1) In the case of Zn 3) Process groups B, C or D in accordance and Cd with DIN 50 941 only apply to however, process cadmium and zinc coatings. In the case of group A other electroplated coatings, "P" in the code symbol signifies "degree of 2) Only applies to Zn coatings gloss optional". Ordering code for electroplated coatings for commercial fasteners

Nominal size metric < 5 mm 5 < 10 mm > 10 mm

Coating Degree of gloss Nominal size inch < 3/16 " 3/16" < 3/8 " > 3/8 "

Zinc-chromated Glossy Glossy Color Color none bluish A1J A1K A2J A2K A3J A3K

Copper Nickel nickel Glossy Glossy Glossy Glossy Color Color yellowish black – – A1L A1T E1J G2J A2L A2T E2J G2J A3L A3T E3J G3J

Example of coding: A3L means zinc-plating (A in Table 1) with a minimum layer thickness of 8 µm (3 in Table 2) and yellow-chromated with a glossy degree of gloss (L in Table 3). Callout Example: Hexagon bolt DIN 931 - M12 x 50 - 8.8 - A3L. Chromate (passivate) effected immediately after electroplating by short immersing in chromic acid solutions. The chromating process increases the corrosion protection and prevents a starting and a discolouring of the zinc layer. The protective effect of the chromate layer is different depending upon group of procedures (see table). Click for: (Ref. ISO 4092) Plating thicknesses for threaded metric fasteners

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Bearings, Hydraulic And Pneumatic Fittings & Tubing, Workholding Components, Plumbing Fittings, & Some Electrical & Electronic Components. Click to go to Maryland Metrics home page Phones: (800) 638-1830 or (410) 358-3130 are available Monday-Friday 8:30 AM to 5:30 PM Eastern time. Faxes: (800) 872-9329 or (410) 358-3142 & E-mail are available anytime. Warehouse & showroom hours are Monday-Friday 10 AM to 5:30 PM. [ To: Maryland Metrics home page ] [ To: Maryland Metrics Product Guide ] [ e-mail to Maryland Metrics ] Please note that all Trademarks and Tradenames are the property of their respective owners. copyright 2006, 2011 maryland metrics -- all rights reserved -- ver gg07fCD 267part9.htm

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Surface Finish Standard

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