1 Aug In order to ensure strict adherence to the specification ASTM A when performing repairs at the galvanizing plant, the galvanizer should be. ASTM A Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings details how to repair a damaged hot-dip galvanized coating . 2. Referenced Documents. ASTM Standards: A Terminology Relating to Metallic Coated Steel Prod- ucts2. D Specification for Zinc Dust Pigment3.
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The method and extent of surface preparation shall be mutually agreeable to the contracting parties. Finally, a visual inspection to confirm the level of cleanliness must astm a780 carried out to ensure the standard is met. Inch-pound units and SI units are astm a780 necessarily exact equivalents. Astm a780 grinding tools include reciprocating sanders, orbital sanders, or grinding devices that utilize abrasive cloths, discs, wheels or flaps.
The damage may be the result of welding or cutting flamein which case the coating will be damaged predominantly by burning.
ASTM AZinc Dust in Paint | American Galvanizer’s Association
Aa780 the paint as recommended by the paint manufacturer in a single application employing multiple spray passes astm a780 achieve a dry film thickness to be agreed upon between the contracting parties. The practice is the same, but there are more restrictions to astm a780 allowable repairs astm a780 a new product than one that astm a780 been in service.
Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.
Where blast or power tool cleaning cannot be performed, hand tool cleaning per SSPC-SP2 Hand Tool Cleaning allows the use of wire brushing, scraping, chipping and sanding.
Topics will include proper equipment and materials to use while performing the astm a780, explanation of the specifications to follow, and examples of best practice during application of the repair materials. Correct for the additional tape thickness i. Astm a780 is no ASTM specification which specifies a maximum allowable repair size for galvanized items already accepted and delivered. The zinc coating is difficult to damage, and field fabrication that requires removal of the coating should be minimized as much as possible.
To ensure that a smooth reconditioned coating can be effected, surface preparation shall extend into the atsm galvanized coating. Galv Touch-Up and Repair Dr. Where such contaminants are found, the surface preparation standards associated with all repair materials require the astm a780 of visible dirt, oil and grease deposits using a solvent cleaning method such as SSPC-SP1 Solvent Cleaning.
The specification explains how to use the various repair methods astm a780 well as the required coating thickness for the astm a780 area. The main restriction in the specification for repairing newly galvanized material is the size of the area which is outlined in the product galvanizing specifications:.
The touch-up and repair of hot-dip galvanized steel coatings is important to maintain uniform barrier and cathodic protection as well as ensure longevity.
Similarly, contracting parties shall agree to the repair method to be used.
This axtm is a brief summary of the referenced standard. Touch-up materials are required to meet a coating thickness of at least 2. In order to ensure strict adherence to the specification ASTM A when performing repairs at the galvanizing plant, the galvanizer should be well versed in a78 equipment, materials and surface preparation standards required of each repair method.
Therefore, once in-field, any size of repairable coating defect can be touched up. This practice can also astm a780 used to repair hot-dip galvanized a870 damaged by excessively rough handling during astm a780 or erection. The area being repaired needs to be preheated to approximately F C. At the astm a780 facility, the maximum astm a780 repair size for iron and steel products per ASTM A is no astm a780 than 1 inch [2. Authored by Alana Hochstein.
Maximum Allowable Repair Size The astm a780 for repairing the galvanized coating in-field is the same as the practice for repair at the galvanizing facility, but there are more restrictions to the allowable repair size while at the galvanizing facility. It is informational only and not an official part of the standard; the full text of the standard astm a780 must be referred to for its use and application.
Link to Active This link will always route to the current Active version of the a870. Do not average the readings, as this requirement was removed from the specifications in The z780 video series will provide asrm beneficial visual aids to those needing assistance with meeting the requirements of ASTM A Ensure a blotter test is performed prior to using a compressed air source in accordance with ASTM D Hand tool cleaning with a stiff-bristle or nylon brush does not meet specification.
Ensuring Conformance to ASTM A780
Where circumstances do not allow blast cleaning, it is permissible to power disk sand areas to awtm repaired to bright metal. For astm a780 surface preparation methods, cleaning must extend into the surrounding, undamaged galvanized coating.
ASTM A contains three acceptable methods of touch-up and repair of hot-dip galvanized steel: Any dust or loose residue from cleaning must be brushed away using a astm a780 brush or blown off using clean, dry air. When ready to perform mechanical cleaning, check astm a780 surface preparation standard for clarity on the allowable tooling methods.
Repairing HDG Steel | American Galvanizer’s Association
Zinc spray, or metallizing, is done astm a780 melting zinc powder or zinc wire in a flame or electric arc and projecting the molten zinc droplets by air or gas onto the surface astm a780 be astm a780. Corrosion resistance w780 service performance are very dependent on the properties of the paint system, the extent of surface preparation, and skills of individual applicators.
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. 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. Zinc-rich paint is applied ashm a clean, dry steel surface s780 either a brush or spray. The videos provide highly beneficial visual aids to those needing assistance astm a780 touch-up and repair, whether in the plant or the field.