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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The rust not only harms the aesthetically smooth look, but also its mechanic needs. Colorful chromate passivation gives corrosion resistance ability of 96 hours according to ASTM B until white spots-intended to parts used in a high corrosive environment —outdoor. Does anybody know this info? BBBBand B The size of the sample and the criteria for compliance are determined by the application of statistics.
Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. The coating shall not be stained or discolored. III zinc plating A discussion started in but continuing through Q. Olive Drab chromate is hrs.
Due to the impracticality of forging or casting separate test specimens, hot-rolled steel specimens may be used to represent forged and cast steel articles. But if you are looking for something indisputably blue, as opposed to clear with a possible slightly bluish cast, this probably requires dye. Electrical charasteristics As much as the last layer of the passivation is thin the electrical resistivity is low.
N633 you for your hard work which the finishing world continues to benefit from. The electroplated article shall be clean and free of damage. III is colorless and not expected to hold up as long as the colored II.
Until a very few years ago chromate conversion coatings were based on hexavalent chromium, and deposited a thick film that was relatively easy to dye. Additional types have been added to permit non-chromate passivate treatments to be used in replacement of hexavalent chromium.
Our plater would like to go to a clear zinc, but our customer is under the assumption that the clear will not do as good a job with corrosion resistance and salt spray life. The Standard default is gold for type II coatings unless otherwise specified. The type of passivation is determined according to the required characteristics, and is divided into groups:. A number in parentheses indicates the year of last reapproval.
No, other colors may not be available if my presumption is right. The black layer has also additional target —prevention of light reflection from the part and is used for optical parts.
II says “colored chromate coatings” meeting 96 hours of salt spray, and III says “colorless wstm conversion coatings” meeting 12 hours of salt spray. The problem may not be with the chromate at all.
We are getting poor coverage on the as-cast surface of some steel castings using a yellow Zinc chromate. Mark Hollenbeck alloys – Muskegon, Michigan A. As much as the last layer of the passivation is thin the electrical resistivity is low.
Zinc Plating: ASTM B Type II vs. III
Olive green passivation is a chromate passivation in a green hue that gives excellent corrosion resistance ability hours in a salt awtm test and is a good base for paint.
This applies to all metals. Corrosion resistance Colorful chromate passivation gives corrosion resistance ability of 96 hours according to ASTM B until white spots-intended to parts used in a high corrosive environment —outdoor.
Regarding the question asked in letter ; Type II zinc plating vs. To minimize problems of this sort, the speci? Zinc coating with colorful RoHS compliance passivation. Does plating make that big a difference knowing that it’s going to be painted also? When such areas are designated, and thus made subject to minimum thickness requirements, the purchaser and the manufacturer shall recognize the necessity for either thicker deposits on other areas or for special racking.
Obviously, this must be clarified by the customer. The Zinc coating provides a smooth look as well as good anti-corrosive protection.
If heavier coatings are required, allowance for the deposit buildup must be made during the manufacture of the threaded articles.