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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I’ve seen this done less commonly on chromated zinc plating than on chromated aluminum. II says “colored chromate coatings” meeting 96 hours of salt spray, and III says “colorless chromate conversion coatings” meeting 12 hours of salt spray.
It still will have Hex Chrome. No it does not imply that. The end user must decide when a part fails, at “white rust” corrosion the chromate has failed or red rust both the chromate and the zinc are gone exposing the base metal.
As the USA moved toward metric fasteners, for a while there was a move to dye them blue. How do you know if it is supposed to be Zinc Yellow or Zinc Clear? Not the least of which is the environmental regulations impact on the future of the selected finish. Our plater would like to go to a clear zinc, v633-85 our customer is under the assumption that the clear will not do as good a job with corrosion resistance and salt spray life.
Zinc coating with colorless RoHS compliance passivation.
The black layer has also additional target —prevention of light reflection from the part and is used for optical parts. We are getting poor coverage on the as-cast surface of some steel castings using a yellow Zinc chromate.
Zinc Plating: ASTM B Type II vs. III
All information presented is for general reference and does not represent a professional opinion nor the policy of an author’s employer.
But if you are looking for something indisputably blue, as opposed to clear with a possible slightly bluish cast, this probably requires dye.
Olive green and Black passivation is thick and has high electrical resistance. August 31, A. Corrosion Resistance B633-885 Types. Any information would be well received. What process variation would produce these different results? B Where service conditions are valid only for coatings with chromate conversion coating.
III zinc plating A discussion started in but continuing through Q. Olive Drab chromate is hrs. So if I’m interpreting this correct, there is both a color difference and a salt spray difference. Thank you aastm your hard work which the finishing world continues to benefit from.
To minimize your searching efforts and to offer multiple viewpoints, we’ve combined some threads into the dialog you’re viewing. Numeral indicates thickness in micrometers. Asm Zinc coating is carried out according to: Rest in peace, Ken. Yellow chromate should get 96 hrs to failure. Colorful RoHS compliance passivation gives corrosion resistance ability of hours according awtm ASTM B until white spots-also intended to parts used in a high corrosive environment —outdoor.
What do you say? The Zinc coating on the steel does not last shiny for long, and so a further thick layer coating is added, called passivation. The designer and engineer must take into account several considerations to stay at the forefront xstm the finish potential. A Iron or steel with zinc electroplate. Go to main content. The revision addresses RoHS concerns and specifically allows non-hexavalent chromate treatments.
ASTM B-633 Type II vs. III zinc plating
No, other colors may not be available if my presumption is right. Try using an acid zinc chloride bath and see if the casting covers. What type of zinc plating bath is your plater using? To determine the nature of accuracy or revision level please verify above data with current releases: The Zinc coating provides a smooth look as well as good anti-corrosive protection.