Zinc [ASTM-B] This specification covers requirements for electrodeposited zinc coatings applied to iron or steel articles. ASTM B ELECTRODEPOSITED COATINGS OF ZINC ON IRON AND STEEL. The coating is made according to demand, where the distribution is as follows. Blue/Zinc. Blue/Zinc. Yellow/Zinc. Yellow/Zinc. ASTM B Type II SC 3 (FE/ZN 13). Type II SC 2 (FE/ZN 8). Type II SC 1 (FE/ZN 5). Type III SC 3(FE/ZN 13).
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The Zinc coating on the steel does not last shiny for long, and so a further thick layer coating is added, called passivation. So if you need to color match, you need to do it with a requirement for compliance with sample parts — not a verbal description.
Corrosion Resistance Requirements Types. The revision addresses RoHS asttm and specifically allows non-hexavalent chromate treatments. All I need to know is what color the types are. To determine the nature of accuracy or revision level please verify above data with current releases: As the USA moved toward metric fasteners, for a while there was a move to dye them blue.
Surfaces left-bare should be heavily chromated. I have the exact same questions. I will be attending the ASTM B8 committee meetings in Philly later this week and will mention this letter to the sub-committee chair responsible for the B spec. According to RoHS the homogeneous and non-homogeneous are defined in such manner that every one may understand that the layer is removable let’s see how.
Does plating make that big a difference knowing that it’s going to be painted also? It does not cover zinc-coated wire or sheets. Asfm need to specify platings that do not contain Hexavalent Chromium for parts that will be used in the automotive industry. No, other colors may not be available if my presumption is right. Mark Hollenbeck alloys – Muskegon, Michigan A.
Go to main content. The part is ashm being produced in China and my local platers are suggesting a dye to get a blue color.
III is colorless and not expected to hold up as long as the colored II.
ASTM B-633 Type II vs. III zinc plating
Certain castings are difficult, if not impossible, to plate in either cyanide or alkaline non-cyanide plating baths.
It’s not possible to diagnose a finishing problem or the hazards of an operation via these pages. Thank you for your hard work which the finishing world continues to benefit from. The Zinc coating provides a smooth look as well as good anti-corrosive protection. Decorative charastreistics The exterior visual determined according to last layer. How do you know if it is supposed to be Zinc Yellow or Zinc Clear?
Obviously, this must be clarified by the customer. Olive green passivation is a chromate passivation in a green hue that gives excellent corrosion resistance ability hours in a salt spray test and is a good base for paint. Try using an acid zinc chloride bath and see if the casting covers.
There are different passivation colors: Put the chromate on light. Kaushik, The “Types” define supplementary finishes to be done after the plating. Zinc coating with colorful chromate passivation. No it does not imply that. Trivalent chromates give paler and lighter finishes; some use metals, some use permanganates, some use dyes, in order to replicate the Hex finish.
Perhaps some confusion with Service Condition SC 2 moderatewhich indicates a minimum zinc thickness of 8 microns and is commonly clear chromated Type III. Did you ever get the answers you were looking for? I am not getting the difference between this. The answer is Yes.
ASTM B datasheet & applicatoin notes – Datasheet Archive
Olive green and Black passivation is thick and has high electrical resistance. Going with clear will make it h633-85 to tell what is clear chromated zinc vs. Please forgive any resultant repetition or failures of chronological order. He passed away May 14, I’m not a zinc plater, but ‘Type II Clear’ seems self-contradictory.
Qstm anybody know this info? The type of passivation is determined according to the required characteristics, and is divided into groups:.
Supplementary treatments shall be in accordance with Recommended Practice B Some of today’s proprietary trivalent chromium coatings are very thin and consequently will not generate a highly saturated color though.
Hello Claudio and Doug, My compliments for an excellent round of questions! You can get the same finish only for blue and black hex chrome with tri substitutes, but not for yellow or olive as of yet.