ASTM B Type II and III zinc chromate plating Q&A’s. greater corrosion resistance is required, e.g., for SC3 & SC4 (13 & 25 microns zinc, respectively). 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). ASTM A/AM Low and Intermediate Tensile Strength Carbon Steel Plates .. ASTM B Electrodeposited Coatings of Zinc on Iron and Steel.
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A heavy chromate will shear under paint and cause the paint to peel. What do you say? Sorry, but if you need one particular look, you must go through the ugly process of maintaining sample boards with acceptable vs. The Zinc coating provides a b6333 look as well as good anti-corrosive protection. The type of passivation is determined according to the required characteristics, and is divided into groups: All I need to know is what color the types are.
Does plating make that big a difference knowing that it’s going to be painted also?
Does anybody know this info? A Blue with pale yellow is the best replacement for yellow as of now.
Answer is based upon pre versions of B, Put the chromate on light. The coating is made according to demand, where the distribution is as follows: As much as the last layer of the passivation is thin the electrical resistivity is low.
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. The type of passivation is determined according to the required characteristics, and is divided into groups:.
Olive Drab chromate asstm hrs.
Try using an acid zinc chloride bath and see if the casting covers. What process variation would produce these different results?
ASTM B-633 Type II vs. III zinc plating
To me “bright blue” does not usually literally mean “bright blue” like the sky or a robin’s egg. We are getting poor coverage on the as-cast surface of some steel castings using a yellow Zinc chromate.
All information presented is for general reference and does not represent a professional opinion nor the policy of an author’s employer. Regarding the question asked in letter ; Type II aatm plating vs.
Could you explain this? II says “colored chromate coatings” meeting 96 hours of salt spray, and III says “colorless chromate conversion coatings” meeting 12 hours of salt spray.
III zinc plating A discussion started in but continuing 133 Q. 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.
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. No, other colors may not be available if my presumption is right. I’m not a zinc plater, but ‘Type II Clear’ seems self-contradictory.
You can wstm the same finish only for blue and black hex chrome with tri substitutes, but not for yellow or olive as of yet.
Olive green and Black passivation is thick v633 has high electrical resistance. Hi, I recently received 2 batches of parts from two separate platers using this specification. From beautiful Pine Beach New Jersey: Surfaces left-bare should be heavily chromated. I am not getting the difference between this. 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.
Yellow chromate should get 96 hrs to failure. Perhaps some asttm with Service Ast SC 2 moderatewhich indicates a minimum zinc thickness of 8 microns and is commonly clear chromated Type III. Mark Hollenbeck alloys – Muskegon, Michigan A. 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. Surfaces asfm be painted should be ONLY lightly chromated.
ASTM B – Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel
I have the exact same questions. What type of zinc plating bath is your plater using? Trivalent chromates give paler and lighter finishes; some use metals, some use permanganates, some use dyes, in order to replicate the Hex finish. Some of today’s proprietary trivalent chromium coatings are very thin and consequently will not generate a highly saturated color though. I’ve seen this done less commonly on chromated zinc astn than on chromated aluminum.
Olive green passivation is a chromate passivation in a green hue that gives excellent corrosion resistance ability b63 in a salt spray test and is a good base for paint.