ASTM B Type II and III zinc chromate plating Q&A’s. *Note: Answer is based upon pre versions of B (, , ). The revision. Hi, can anyone advise if the ASTM std ASTM B [link by ed. to spec at TechStreet] std specification for Electroplated coatings on Iron and steel, the . ASTM Be1 Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel Scope This specification covers requirements .
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Our plater would like to go to wstm 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. I need to specify platings that do not contain Hexavalent Chromium for parts that will be used in the automotive industry.
It does not cover zinc-coated wire or sheets. Surfaces to be painted astk be ONLY lightly chromated. Trivalent chromates give paler and lighter finishes; some use metals, some b33-98 permanganates, some use dyes, in order to replicate the Hex finish.
Numeral indicates thickness in micrometers. The designer and engineer must take into account several considerations to stay at the forefront of the finish potential. The part is awtm being produced in China and my local platers are suggesting a dye to get a blue color. 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. Thank you for your hard work which the finishing world continues to benefit from.
The answer is Yes.
Different brands of chromate conversion chemistry, possibly different plating processes acid zinc vs. Regarding the question asked in letter ; Type II zinc plating vs. So if I’m interpreting this correct, there is both a color difference and a salt spray difference.
To me “bright blue” does not usually literally mean “bright blue” like the sky or a robin’s egg. I’ve seen this done less commonly on chromated zinc plating than on chromated aluminum. Some of today’s proprietary trivalent chromium coatings are very thin and consequently will not generate a highly saturated color though.
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. Corrosion Resistance Requirements Types.
ASTM B-633 Type II vs. III zinc plating
Did asstm ever aastm the answers you were looking for? Zinc plated components vary from one industry to another. I’m not a zinc plater, but ‘Type II Clear’ seems self-contradictory. This is not considered a decorative finish and will not generate matching parts. The above entries are somewhat dated: So if you need to color match, you need to do it with a requirement for compliance with sample parts — not a verbal description.
This applies to all metals. Supplementary treatments shall be in accordance with Recommended Practice B August 31, A. All I need to know is what color the types are.
That seems a bit discretional to me. Going with clear will make it difficult to tell what is clear chromated zinc vs. No, other colors may not be available if my presumption is right. It would be “bright, blue” — that is, shiny and metallic but b633–98 a bluish rather than a yellowish cast. Perhaps some confusion with Service Condition SC 2 moderatewhich indicates a minimum zinc thickness of 8 microns and is commonly clear chromated Type III.
From beautiful Pine Beach New Jersey: SC 4 very severe. To minimize your searching efforts and to offer multiple viewpoints, we’ve combined some threads into axtm dialog you’re viewing.
Please forgive any resultant repetition or failures of chronological order.
ASTM B – 98 Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel
I have the exact same questions. How do you know if it is supposed to be Zinc Yellow or Zinc Clear? A heavy chromate will shear aetm paint and cause the paint to peel. Mark Hollenbeck alloys – Muskegon, Michigan A. III zinc plating A discussion started in but continuing through Q. ASTM B and all other worldwide standards were written around the time when no one spoke about trivalent.
Is this b633-98 done in the United States, and if so by whom? Does anybody know this info? They share, however, the most basic of metal finishing requirements: Obviously, this must be clarified by the customer. Zinc and Zinc alloys, such as zinc-nickel will surely play a more significant role as metals such as Cadmium are destined for the elements’ Valhalla. Any information would be well received.
ASTM B633-98 std: Electrodeposited coating of Zinc
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. Not the least of which is the environmental regulations impact on the future of the selected finish.
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