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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Since the bolts are pre-tensioned, will there be any issues with Magni with regard to pre-tensioning i.
High Strength Bolts Coatings – Portland Bolt
Consulting a structural engineer involved on the project is always the best solution. Bandana- There are no issues mixing coatings with DTI washers. As for the thickness of both coatings, F grade 3 specified a coating thickness of 0. It is required that the bolt and nut are coated by the same process, but the washer can be an alternate coating. Leave a Reply Cancel reply Your email address will not be published.
I suppose they are similar to painting. 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.
Pierre-Paul — The properties of the bolt and the final tension should not be impacted. Serge- We have very little experience with Dacromet coating. Protective Coatings ASTM recommends that if a protective coating is required ast A bolts, one of two approved coatings is recommended.
The basecoat axtm contain chrome C or be non-chrome NC. The bolts and nuts are already coated with Dacromet and the proposal is to coat the DTI washers with Magni Since the Dacromet and Magni will be in contact with one another, Are they compatible with one another?
One year after installation the bolts are rusting. Historical Version s – view previous versions of standard. This abstract is a brief summary of the referenced standard.
We assumed that the properties on the bolts is not affected but the final tension might be change? 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. F Grade 3, commonly known as Dacromet.
Jovito- We would be happy to quote your asym bolting needs if you want to send us a list of the bolts you are looking for. Hello, We have specified A Dracomet coated bolts for a telecommunications monopole in Canada. Although hot-dip galvanize 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.
I do not have any friction coefficient information on Magniso I do not know how much the torque will be affected. 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. However, these fasteners are not as readily available in the marketplace as A Type 1.
What corrosion-resistant coatings are available for high-strength over ksi bolts? If so, did the tension will be higher? Parham- We cannot make specific recommendations, but I can say that painting A bolts is quite common.
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. I am using A grade BC and need a smooth finish with minimal irregularities. We also see no issues with pre-tensioning. Normally where I see F specified is in applications with higher strength fasteners that cannot be hot-dip galvanized, such as ASTM A heavy hex bolts.
Since we are using A bolts in our structure, we have to propose a replacement.
It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
No metric equivalents are presented in this specification. We are not sure how fragile the coating is during installation. Link to Active This link will always route to the current Active version of the standard. Is the coating that fragile? Work Item s – proposed revisions of this standard.
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.
Hi, Recently we were informed that Dacromet coating is being phased out.