This standard is issued under the fixed designation F ; the 1 This specification is under the jurisdiction of ASTM Committee F16 on. ASTM: F – Standard Specification for Chromium/Zinc Corrosion Protective Coatings for Fasteners. 1. Scope This specification covers the basic. ASTM F/FM Standard Specification for Zinc/Aluminum Corrosion Protective Coatings for Fasteners. standard by ASTM.
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Is the coating that fragile? Leave this field empty. Hi, Recently we ast, informed that Dacromet coating is being phased out. They were used to in flange type splices of two tubular monopole sections.
As for the thickness of both coatings, F grade 3 specified a coating thickness of 0.
I do not have any friction coefficient information on Magniso I do not know how much the torque will be affected. Since we are using A bolts in our structure, we have to propose a replacement.
Since the Dacromet asstm Magni will be in contact with one another, Are they compatible with one another?
What corrosion-resistant coatings are available for high-strength over ksi bolts? Hot-dip galvanized hex nuts are therefore tapped oversize to accommodate the thick coating, whereas F specifically states that the thread fit shall not be adversely affected. Work Xstm s – proposed revisions of this standard. We assumed that the properties on the bolts is not affected but the final tension might be change?
Protective Coatings ASTM recommends that if a protective coating is required for A bolts, one of two approved coatings is recommended. But there are some doubts. The tightening torque may vary from plain finish or other coatings, but the bolt should still function the same. This abstract is a brief summary of the referenced standard.
High Strength Bolts Coatings – Portland Bolt
We also see no issues with pre-tensioning. No other units of measurement are included in this standard. So what are the alternatives to provide corrosion resistance for A structural bolts? F Grade 3, commonly known as Dacromet. Parham- We cannot make specific recommendations, but I can say that painting A bolts is quite common. The basecoat can contain chrome C or be non-chrome NC.
Consulting a structural engineer involved on the project is always the best solution. I suppose they are similar to painting. Historical Version s – view previous versions of standard.
High Strength Bolts Coatings
Your first question, is it appropriate to specify ASTM F Grade 3would be best answered by an engineer familiar with the coating and the application. Link to Active This link will always route to the current Active version of the standard.
Is fluorocarbon coating acceptable to A bolts for corrosion prevention? The coatings are classified into six grades Grades 1 to 6 according to the required minimum basecoat thickness, and when tested, shall conform accordingly to appearance, adhesion, corrosion resistance, blister, thread fit, and hydrogen embrittlement requirements. The bolts and nuts are already coated with Dacromet and the proposal is to coat the DTI washers with Magni That said, I do not know much about fluorocarbon coatings and how they are applied.
This fastener is made from weathering steel which is inherently corrosion resistant. We are not sure how fragile the coating is during installation. Serge- We have very little experience with Dacromet coating.
It is required that the bolt and nut are coated by the same process, but the washer can be an alternate coating. Due to hydrogen embrittlement concerns ASTM recommends against hot-dip galvanizingmechanical deposition, or electroplating with zinc or other metallic coatings on high strength bolts ultimate tensile strengths that exceed ksi.
Alkaline cleaning or vapor degreasing is required along with shot blasting to remove rust or scale.
One year after installation the bolts are rusting. Bandana- There are no issues mixing coatings with DTI washers. Leave a Reply Cancel reply Your email address will not be published.
I am using A grade BC and need a smooth finish with minimal irregularities.
Although hot-dip f1136 provides high thickness level barrier protection 2 mils for substrates, it is not approved for use on high strength bolts because hot dip galvanize is susceptible of hydrogen embrittlement and cracking of fasteners that can result out in the field. 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.
Hello, We have specified A Dracomet coated bolts for a telecommunications monopole in Canada. If so, did the tension will be higher? A coatings engineer may choose to allow an exception in some cases, but ASTM will not officially sanction any coatings that are not approved by the F16 committee.