ASTM B() Standard Specification for Chromates on Aluminum Scope
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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. Chromate Conversion Coating also commonly referred to as Chemical Film, Chem Film, Astn 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.
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. July 21, Q. Those specs are somewhat similar, but I do not think there is any claim that they are “technically equivalent”. Asttm provides excellent corrosion resistance, is conductive and results in no measurable buildup 0.
But even if you do, I’d suggest that you not certify compliance to a spec you don’t have on hand. It is commonly used for an undercoat for paint or adhesive applications due to the excellent bonding properties it provides. Chromate conversion coatings are the most widely used coating for corrosion protection of Aluminum and Aluminum alloys minimizing surface oxidation. We test coating wt. S October 11, A. Class 3- Clear or Yellow For protection against corrosion where low electrical resistance is required.
Chromate conversion coatings are normally applied by dipping: It’s not possible to diagnose a finishing problem or the hazards of an operation via these pages. Joe Roter – Chatsworth, California, U. 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 compares favorably with the hexavalent coatings providing a conversion coating that fulfills the corrosion, paint and electrical requirements of the different specifications. I don’t believe coating wt. It might be worth getting your customers to waive or except the requirement in writing, assuming your coupons are passing the SS test.
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 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.
Greg, it sure looks like it is available from ASTM at: Class 1A coatings give maximum corrosion protection with the highest electrical surface resistance while class 3 coatings have lower corrosion protection and asrm lower electrical surface resistance.
Chromate Conversion Coating
Type II- Compositions containing no hexavalent chromium Class 1A- Clear For maximum protection against corrosion, painted or unpainted. Your Metal Finishing Solution.
The materials are classified according to its coating thickness: Yes, a rough correspondence between what comprises class 2 vs. This abstract is a brief summary of the referenced standard. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of b449-3 limitations prior to use.
Class 3- Clear For protection against corrosion where low electrical resistance is required. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. From beautiful Pine Beach New Jersey: I can vouch that their pdf delivery works well at least on my computer, it did All information presented is for general reference and does not represent a professional opinion nor the policy of an author’s employer.
Both Hexavalent and Trivalent films at Advanced Surface Technologies have passed initial hour salt spray testing and are subject to monthly hour salt spray testing as well as paint adhesion testing conforming to all specifications. October 9, A. 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.
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ASTM B-449 Spec for Chromating Aluminum
ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date. No other units of measurement are included in this 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.
July 22, A. Class 1; Class 2; Class 3; and Class 4. Class 1A- Yellow For maximum protection against corrosion, painted or unpainted. Thank you for your answer. Historical Version s – view previous versions b449-39 standard.
Thank you for your help. Class 1A- Clear For maximum protection against corrosion, painted or unpainted.