ASTM B Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel. Buy ASTM B SPECIFICATION FOR ELECTRODEPOSITED COATINGS OF ZINC ON IRON AND STEEL from SAI Global. ASTM B Type II and III zinc chromate plating Q&A’s. In my opinion a Mil-C- [link is to free spec at Defense Logistics Agency, ] plating.
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It does not cover electrodeposited zinccoated steel wire or sheets see Speci? The Zinc coating on the steel does not last shiny for long, and so a further thick layer aatm is added, called passivation. Therefore, it is recommended that supplementary treatments not be applied to zinc coatings having a nominal thickness less than 5?
So if I’m interpreting this correct, there is both a color difference and a salt spray difference. Conditions affecting the electroplating of specimens, including the spacing, plating media, bath agitation, temperature, etc.
Zinc Plating: ASTM B Type II vs. III
Surfaces to be painted should be ONLY lightly chromated. III is colorless and not expected to hold up as long as the colored II. Yellow-iridescent Black Olive Green. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every?
Originally approved in Olive Drab chromate is hrs. Except as otherwise speci? For corrosion resistance requirements, see Table 2. Also, some yellow chromates are clear w.
The size of the sample and the criteria for compliance are determined by the application of statistics.
Is there any colour difference OR is there any Salt spray difference? The coating is made according to demand, where the distribution is as follows: When Test Methods BBor B are used, remove the supplementary treatment prior to testing.
It’s not possible to diagnose a finishing problem or the hazards of an operation via these pages. The part is currently being produced in China and my local platers are suggesting a dye to get a blue color. Type II chromates are more commonly used where greater corrosion resistance is required, e. Unless a need can be demonstrated, separately prepared specimens shall not be used in place of production items for nondestructive and visual examinations. Zinc coating with colorful chromate passivation.
No, other colors may not be available if my presumption is right. What type of zinc plating bath is your plater using? Iridescent and Colorless passivation is thin and has low electrical resistance.
NOTE 5—Thickness methods that rely on the purity of the zinc deposit may not be sufficiently accurate when evaluating coatings produced from non-cyanide zinc solutions. It would be “bright, blue” — that is, shiny and metallic but with a bluish rather than a yellowish cast. Regarding the question asked in letter ; Type II zinc plating vs. 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.
The revision addresses RoHS concerns and specifically allows non-hexavalent chromate treatments. These separate specimens shall be introduced into a lot at regular intervals before the cleaning operations, preliminary to electroplating, and shall not be separated therefrom until after completion of electroplating.
How do you know if it is supposed to be Zinc Yellow or Zinc Clear? We are getting poor coverage on the as-cast surface of some steel castings using a yellow Zinc chromate. The purchaser may similarly require that a report of the test results be furnished. There are different passivation colors: Could you explain this?
To minimize your searching efforts and to offer multiple viewpoints, we’ve combined some threads into the dialog you’re viewing. Available colors are iridescent and black Colorless chromate passivation gives corrosion resistance ability of 12 hours according to ASTM B until white spots-intended to parts used in a light corrosive environment —indoor.
The Zinc coating provides a smooth look as well as good anti-corrosive protection. The electrical resistance of this green layer passivation is very high because it is thick in relative to other passivations.