ASTM B Standard Specification for Chromates on Aluminum. Advanced Plating Technologies, a Milwaukee company, offers Aluminum Chromate Conversion Coatings per MIL-C (MIL-DTL) and ASTM B CHEMICAL FILMS ASTM-B/MIL-C CLASS 1A. Materials qualified produce coatings that range in color from clear to iridescent yellow or brown.
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No other units of measurement are included in this standard. Aluminum and aluminum alloys are chromate coated in order to retard corrosion; as a base for organic films including paints, plastics, and adhesives; and as a protective coating having a low electrical contact impedance.
Historical Version s – view asfm versions of standard.
This specification covers the requirements relating to rinsed and non rinsed chromate conversion coatings on aluminum and aluminum alloys intended to give protection against corrosion and as a base for other coatings. Thank you for your help. It is commonly used for an undercoat for paint or adhesive applications due to the excellent bonding properties it provides. Class 1- Yellow to Brown, Maximum corrosion resistance generally used as final finish Class 2- Colorless to yellow, Moderate corrosion resistance, used as a paint base and for bonding to rubber Class 3- Colorless, Decorative, slight corrosion resistance, low electrical contact resistance Class 4- light green to green, Moderate corrosion resistance, used as a paint base and for bonding to rubber Not done at AST.
Class 3- Clear or Yellow For protection against corrosion where low electrical resistance is required. Chromate Conversion Coating also commonly referred to as Chemical Film, Chem Film, Alodine or Iridite converts the surface properties of the substrate typically aluminum or magnesium as compared to plating which applies a coating onto the surface of the substrate.
Joe Roter – Chatsworth, California, U.
All information presented is for general reference satm does not represent a professional opinion nor the policy of an author’s employer. Chromate Classes Class 1- Yellow to Brown, Maximum corrosion resistance generally used as final finish Class 2- Colorless to yellow, Moderate corrosion resistance, used as a paint base 4b49 for bonding to rubber Class 3- Colorless, Decorative, slight corrosion resistance, low electrical contact resistance Class 4- light green to green, Moderate corrosion resistance, used as a paint base and for bonding to rubber Not done at AST.
Class 1; Class 2; Class 3; and Class 4.
July 22, Sstm. Chromate conversion coatings are normally applied by dipping: We get a small commission for maintaining their links, so we can keep them perpetually current Type II- Compositions containing no hexavalent chromium Class 1A- Clear For maximum protection against corrosion, painted or unpainted.
Thank you for your answer. Those specs are somewhat similar, but I do not think there is any claim that they are “technically equivalent”.
Advanced Surface Technologies extensive experience with the chromate process enables us to effectively process cast and all the different wrought alloys with alloy specific pre-treatment chemistries. Your Metal Finishing Solution.
Chromate conversion coatings are the most widely used coating for corrosion protection of Aluminum and Aluminum alloys minimizing surface oxidation. Class 1A- Yellow For maximum protection against corrosion, painted or unpainted.
The h449 are classified according to its coating thickness: Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. It’s not possible to diagnose a finishing problem or the hazards of an operation via these pages.
I can vouch that their pdf delivery works well at least on my computer, it did S October 11, A. I don’t believe coating wt. Asym even if you do, I’d suggest that you not certify compliance to a spec you don’t have on hand.
It might be worth getting your customers to waive or except the requirement in writing, assuming your coupons are passing the SS test. Yes, a rough correspondence between what comprises class 2 vs.
July 21, Q. Class 1A- Clear For maximum protection against corrosion, painted or unpainted. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. It is included in our internal testing matrix, but none of our customers require it and I can not find it in MIL-C, so I would like to remove it from monthly testing.
It compares favorably with the hexavalent coatings providing a conversion coating that fulfills the corrosion, paint and electrical requirements of the different specifications. This abstract is a brief summary of the referenced standard. Class 1A coatings give maximum corrosion protection with the highest electrical surface resistance while class 3 coatings have lower corrosion protection and provide lower electrical surface resistance.
Link to Active This link will always route to the current Active version of the standard.